/*-
 * #%L
 * HAPI FHIR Storage api
 * %%
 * Copyright (C) 2014 - 2025 Smile CDR, Inc.
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * #L%
 */
package ca.uhn.fhir.jpa.dao;

import ca.uhn.fhir.context.FhirContext;
import ca.uhn.fhir.context.FhirVersionEnum;
import ca.uhn.fhir.context.RuntimeResourceDefinition;
import ca.uhn.fhir.i18n.Msg;
import ca.uhn.fhir.interceptor.api.HookParams;
import ca.uhn.fhir.interceptor.api.IInterceptorBroadcaster;
import ca.uhn.fhir.interceptor.api.Pointcut;
import ca.uhn.fhir.interceptor.model.ReadPartitionIdRequestDetails;
import ca.uhn.fhir.interceptor.model.RequestPartitionId;
import ca.uhn.fhir.interceptor.model.TransactionWriteOperationsDetails;
import ca.uhn.fhir.jpa.api.dao.DaoRegistry;
import ca.uhn.fhir.jpa.api.dao.IFhirResourceDao;
import ca.uhn.fhir.jpa.api.dao.IJpaDao;
import ca.uhn.fhir.jpa.api.model.DaoMethodOutcome;
import ca.uhn.fhir.jpa.api.model.DeleteConflict;
import ca.uhn.fhir.jpa.api.model.DeleteConflictList;
import ca.uhn.fhir.jpa.api.model.DeleteMethodOutcome;
import ca.uhn.fhir.jpa.api.model.LazyDaoMethodOutcome;
import ca.uhn.fhir.jpa.cache.IResourceVersionSvc;
import ca.uhn.fhir.jpa.cache.ResourcePersistentIdMap;
import ca.uhn.fhir.jpa.dao.tx.HapiTransactionService;
import ca.uhn.fhir.jpa.dao.tx.IHapiTransactionService;
import ca.uhn.fhir.jpa.delete.DeleteConflictUtil;
import ca.uhn.fhir.jpa.model.config.PartitionSettings;
import ca.uhn.fhir.jpa.model.cross.IBasePersistedResource;
import ca.uhn.fhir.jpa.model.entity.ResourceTable;
import ca.uhn.fhir.jpa.model.entity.StorageSettings;
import ca.uhn.fhir.jpa.model.search.StorageProcessingMessage;
import ca.uhn.fhir.jpa.partition.IRequestPartitionHelperSvc;
import ca.uhn.fhir.jpa.searchparam.extractor.ResourceIndexedSearchParams;
import ca.uhn.fhir.jpa.searchparam.matcher.InMemoryMatchResult;
import ca.uhn.fhir.jpa.searchparam.matcher.InMemoryResourceMatcher;
import ca.uhn.fhir.jpa.searchparam.matcher.SearchParamMatcher;
import ca.uhn.fhir.jpa.util.TransactionSemanticsHeader;
import ca.uhn.fhir.model.api.ResourceMetadataKeyEnum;
import ca.uhn.fhir.model.valueset.BundleEntryTransactionMethodEnum;
import ca.uhn.fhir.parser.DataFormatException;
import ca.uhn.fhir.parser.IParser;
import ca.uhn.fhir.rest.api.Constants;
import ca.uhn.fhir.rest.api.PatchTypeEnum;
import ca.uhn.fhir.rest.api.PreferReturnEnum;
import ca.uhn.fhir.rest.api.RestOperationTypeEnum;
import ca.uhn.fhir.rest.api.server.RequestDetails;
import ca.uhn.fhir.rest.api.server.SystemRequestDetails;
import ca.uhn.fhir.rest.api.server.storage.DeferredInterceptorBroadcasts;
import ca.uhn.fhir.rest.api.server.storage.IResourcePersistentId;
import ca.uhn.fhir.rest.api.server.storage.TransactionDetails;
import ca.uhn.fhir.rest.param.ParameterUtil;
import ca.uhn.fhir.rest.server.RestfulServerUtils;
import ca.uhn.fhir.rest.server.exceptions.BaseServerResponseException;
import ca.uhn.fhir.rest.server.exceptions.InternalErrorException;
import ca.uhn.fhir.rest.server.exceptions.InvalidRequestException;
import ca.uhn.fhir.rest.server.exceptions.MethodNotAllowedException;
import ca.uhn.fhir.rest.server.exceptions.NotModifiedException;
import ca.uhn.fhir.rest.server.exceptions.PayloadTooLargeException;
import ca.uhn.fhir.rest.server.exceptions.PreconditionFailedException;
import ca.uhn.fhir.rest.server.method.BaseMethodBinding;
import ca.uhn.fhir.rest.server.method.BaseResourceReturningMethodBinding;
import ca.uhn.fhir.rest.server.method.UpdateMethodBinding;
import ca.uhn.fhir.rest.server.servlet.ServletRequestDetails;
import ca.uhn.fhir.rest.server.servlet.ServletSubRequestDetails;
import ca.uhn.fhir.rest.server.util.CompositeInterceptorBroadcaster;
import ca.uhn.fhir.rest.server.util.ServletRequestUtil;
import ca.uhn.fhir.util.AsyncUtil;
import ca.uhn.fhir.util.BundleUtil;
import ca.uhn.fhir.util.ElementUtil;
import ca.uhn.fhir.util.FhirTerser;
import ca.uhn.fhir.util.ResourceReferenceInfo;
import ca.uhn.fhir.util.StopWatch;
import ca.uhn.fhir.util.UrlUtil;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.ListMultimap;
import jakarta.annotation.Nonnull;
import jakarta.annotation.Nullable;
import org.apache.commons.lang3.RandomUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.ThreadUtils;
import org.apache.commons.lang3.Validate;
import org.hl7.fhir.dstu3.model.Bundle;
import org.hl7.fhir.exceptions.FHIRException;
import org.hl7.fhir.instance.model.api.IBase;
import org.hl7.fhir.instance.model.api.IBaseBinary;
import org.hl7.fhir.instance.model.api.IBaseBundle;
import org.hl7.fhir.instance.model.api.IBaseExtension;
import org.hl7.fhir.instance.model.api.IBaseOperationOutcome;
import org.hl7.fhir.instance.model.api.IBaseParameters;
import org.hl7.fhir.instance.model.api.IBaseReference;
import org.hl7.fhir.instance.model.api.IBaseResource;
import org.hl7.fhir.instance.model.api.IIdType;
import org.hl7.fhir.instance.model.api.IPrimitiveType;
import org.hl7.fhir.r4.model.IdType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.task.TaskExecutor;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.support.TransactionCallback;
import org.springframework.transaction.support.TransactionTemplate;

import java.time.Duration;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

import static ca.uhn.fhir.util.HapiExtensions.EXTENSION_TRANSACTION_ENTRY_PARTITION_IDS;
import static ca.uhn.fhir.util.StringUtil.toUtf8String;
import static java.util.Objects.isNull;
import static org.apache.commons.lang3.ObjectUtils.defaultIfNull;
import static org.apache.commons.lang3.ObjectUtils.getIfNull;
import static org.apache.commons.lang3.StringUtils.defaultString;
import static org.apache.commons.lang3.StringUtils.isBlank;
import static org.apache.commons.lang3.StringUtils.isNotBlank;

public abstract class BaseTransactionProcessor {

        public static final String URN_PREFIX = "urn:";
        public static final String URN_PREFIX_ESCAPED = UrlUtil.escapeUrlParam(URN_PREFIX);
        public static final Pattern UNQUALIFIED_MATCH_URL_START = Pattern.compile("^[a-zA-Z0-9_-]+=");
        public static final Pattern INVALID_PLACEHOLDER_PATTERN = Pattern.compile("[a-zA-Z]+:.*");

        private static final Logger ourLog = LoggerFactory.getLogger(BaseTransactionProcessor.class);
        private static final String POST = "POST";
        private static final String PUT = "PUT";
        private static final String DELETE = "DELETE";
        private static final String PATCH = "PATCH";

        @Autowired
        private IRequestPartitionHelperSvc myRequestPartitionHelperService;

        @Autowired
        private PlatformTransactionManager myTxManager;

        @Autowired
        private FhirContext myContext;

        @Autowired
        @SuppressWarnings("rawtypes")
        private ITransactionProcessorVersionAdapter myVersionAdapter;

        @Autowired
        private DaoRegistry myDaoRegistry;

        @Autowired
        private IInterceptorBroadcaster myInterceptorBroadcaster;

        @Autowired
        protected IHapiTransactionService myHapiTransactionService;

        @Autowired
        private StorageSettings myStorageSettings;

        @Autowired
        PartitionSettings myPartitionSettings;

        @Autowired
        private InMemoryResourceMatcher myInMemoryResourceMatcher;

        @Autowired
        private SearchParamMatcher mySearchParamMatcher;

        @Autowired
        private ThreadPoolFactory myThreadPoolFactory;

        private TaskExecutor myExecutor;

        @Autowired
        private IResourceVersionSvc myResourceVersionSvc;

        @VisibleForTesting
        public void setStorageSettings(StorageSettings theStorageSettings) {
                myStorageSettings = theStorageSettings;
        }

        public ITransactionProcessorVersionAdapter getVersionAdapter() {
                return myVersionAdapter;
        }

        @VisibleForTesting
        public void setVersionAdapter(ITransactionProcessorVersionAdapter theVersionAdapter) {
                myVersionAdapter = theVersionAdapter;
        }

        private TaskExecutor getTaskExecutor() {
                if (myExecutor == null) {
                        myExecutor = myThreadPoolFactory.newThreadPool(
                                        myStorageSettings.getBundleBatchPoolSize(),
                                        myStorageSettings.getBundleBatchMaxPoolSize(),
                                        "bundle-batch-");
                }
                return myExecutor;
        }

        public <BUNDLE extends IBaseBundle> BUNDLE transaction(
                        RequestDetails theRequestDetails, BUNDLE theRequest, boolean theNestedMode) {
                String actionName = "Transaction";

                IInterceptorBroadcaster compositeBroadcaster =
                                CompositeInterceptorBroadcaster.newCompositeBroadcaster(myInterceptorBroadcaster, theRequestDetails);

                // Interceptor call: STORAGE_TRANSACTION_PROCESSING
                if (compositeBroadcaster.hasHooks(Pointcut.STORAGE_TRANSACTION_PROCESSING)) {
                        HookParams params = new HookParams()
                                        .add(RequestDetails.class, theRequestDetails)
                                        .addIfMatchesType(ServletRequestDetails.class, theRequest)
                                        .add(IBaseBundle.class, theRequest);
                        compositeBroadcaster.callHooks(Pointcut.STORAGE_TRANSACTION_PROCESSING, params);
                }

                IBaseBundle response;
                // Interceptor call: STORAGE_TRANSACTION_PRE_PARTITION
                if (compositeBroadcaster.hasHooks(Pointcut.STORAGE_TRANSACTION_PRE_PARTITION)) {
                        response = new TransactionPartitionProcessor<BUNDLE>(
                                                        this, myContext, theRequestDetails, theNestedMode, compositeBroadcaster, actionName)
                                        .execute(theRequest);
                } else {
                        response = processTransactionAsSubRequest(theRequestDetails, theRequest, actionName, theNestedMode);
                }

                List<IBase> entries = myVersionAdapter.getEntries(response);
                for (int i = 0; i < entries.size(); i++) {
                        if (ElementUtil.isEmpty(entries.get(i))) {
                                entries.remove(i);
                                i--;
                        }
                }

                return (BUNDLE) response;
        }

        public IBaseBundle collection(final RequestDetails theRequestDetails, IBaseBundle theRequest) {
                String transactionType = myVersionAdapter.getBundleType(theRequest);

                if (!org.hl7.fhir.r4.model.Bundle.BundleType.COLLECTION.toCode().equals(transactionType)) {
                        throw new InvalidRequestException(
                                        Msg.code(526) + "Can not process collection Bundle of type: " + transactionType);
                }

                ourLog.info(
                                "Beginning storing collection with {} resources",
                                myVersionAdapter.getEntries(theRequest).size());

                TransactionTemplate txTemplate = new TransactionTemplate(myTxManager);
                txTemplate.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRES_NEW);

                IBaseBundle resp =
                                myVersionAdapter.createBundle(org.hl7.fhir.r4.model.Bundle.BundleType.BATCHRESPONSE.toCode());

                List<IBaseResource> resources = new ArrayList<>();
                for (final Object nextRequestEntry : myVersionAdapter.getEntries(theRequest)) {
                        IBaseResource resource = myVersionAdapter.getResource((IBase) nextRequestEntry);
                        resources.add(resource);
                }

                IBaseBundle transactionBundle = myVersionAdapter.createBundle("transaction");
                for (IBaseResource next : resources) {
                        IBase entry = myVersionAdapter.addEntry(transactionBundle);
                        myVersionAdapter.setResource(entry, next);
                        myVersionAdapter.setRequestVerb(entry, "PUT");
                        myVersionAdapter.setRequestUrl(
                                        entry, next.getIdElement().toUnqualifiedVersionless().getValue());
                }

                transaction(theRequestDetails, transactionBundle, false);

                return resp;
        }

        @SuppressWarnings("unchecked")
        private void populateEntryWithOperationOutcome(BaseServerResponseException caughtEx, IBase nextEntry) {
                myVersionAdapter.populateEntryWithOperationOutcome(caughtEx, nextEntry);
        }

        @SuppressWarnings("unchecked")
        private void handleTransactionCreateOrUpdateOutcome(
                        IdSubstitutionMap theIdSubstitutions,
                        Map<IIdType, DaoMethodOutcome> theIdToPersistedOutcome,
                        IIdType theNextResourceId,
                        DaoMethodOutcome theOutcome,
                        IBase theNewEntry,
                        String theResourceType,
                        IBaseResource theRes,
                        RequestDetails theRequestDetails) {
                IIdType newId = theOutcome.getId().toUnqualified();
                IIdType resourceId =
                                isPlaceholder(theNextResourceId) ? theNextResourceId : theNextResourceId.toUnqualifiedVersionless();
                if (!newId.equals(resourceId)) {
                        if (!theNextResourceId.isEmpty()) {
                                theIdSubstitutions.put(resourceId, newId);
                        }
                        if (isPlaceholder(resourceId)) {
                                /*
                                 * The correct way for substitution IDs to be is to be with no resource type, but we'll accept the qualified kind too just to be lenient.
                                 */
                                IIdType id = myContext.getVersion().newIdType();
                                id.setValue(theResourceType + '/' + resourceId.getValue());
                                theIdSubstitutions.put(id, newId);
                        }
                }

                populateIdToPersistedOutcomeMap(theIdToPersistedOutcome, newId, theOutcome);

                if (shouldSwapBinaryToActualResource(theRes, theResourceType, theNextResourceId)) {
                        theRes = theIdToPersistedOutcome.get(newId).getResource();
                }

                if (theOutcome.getCreated()) {
                        myVersionAdapter.setResponseStatus(theNewEntry, toStatusString(Constants.STATUS_HTTP_201_CREATED));
                } else {
                        myVersionAdapter.setResponseStatus(theNewEntry, toStatusString(Constants.STATUS_HTTP_200_OK));
                }

                Date lastModified = getLastModified(theRes);
                myVersionAdapter.setResponseLastModified(theNewEntry, lastModified);

                if (theOutcome.getOperationOutcome() != null) {
                        myVersionAdapter.setResponseOutcome(theNewEntry, theOutcome.getOperationOutcome());
                }

                if (theRequestDetails != null) {
                        String prefer = theRequestDetails.getHeader(Constants.HEADER_PREFER);
                        PreferReturnEnum preferReturn =
                                        RestfulServerUtils.parsePreferHeader(null, prefer).getReturn();
                        if (preferReturn != null) {
                                if (preferReturn == PreferReturnEnum.REPRESENTATION) {
                                        if (theOutcome.getResource() != null) {
                                                theOutcome.fireResourceViewCallbacks();
                                                myVersionAdapter.setResource(theNewEntry, theOutcome.getResource());
                                        }
                                }
                        }
                }
        }

        /**
         * Method which populates entry in idToPersistedOutcome.
         * Will store whatever outcome is sent, unless the key already exists, then we only replace an instance if we find that the instance
         * we are replacing with is non-lazy. This allows us to evaluate later more easily, as we _know_ we need access to these.
         */
        private void populateIdToPersistedOutcomeMap(
                        Map<IIdType, DaoMethodOutcome> idToPersistedOutcome, IIdType newId, DaoMethodOutcome outcome) {
                // Prefer real method outcomes over lazy ones.
                if (idToPersistedOutcome.containsKey(newId)) {
                        if (!(outcome instanceof LazyDaoMethodOutcome)) {
                                idToPersistedOutcome.put(newId, outcome);
                        }
                } else {
                        idToPersistedOutcome.put(newId, outcome);
                }
        }

        private Date getLastModified(IBaseResource theRes) {
                return theRes.getMeta().getLastUpdated();
        }

        IBaseBundle processTransactionAsSubRequest(
                        RequestDetails theRequestDetails, IBaseBundle theRequest, String theActionName, boolean theNestedMode) {
                return processTransactionAsSubRequest(
                                theRequestDetails, new TransactionDetails(), theRequest, theActionName, theNestedMode);
        }

        IBaseBundle processTransactionAsSubRequest(
                        RequestDetails theRequestDetails,
                        TransactionDetails theTransactionDetails,
                        IBaseBundle theRequest,
                        String theActionName,
                        boolean theNestedMode) {
                BaseStorageDao.markRequestAsProcessingSubRequest(theRequestDetails);
                try {
                        return processTransaction(
                                        theRequestDetails, theTransactionDetails, theRequest, theActionName, theNestedMode);
                } finally {
                        BaseStorageDao.clearRequestAsProcessingSubRequest(theRequestDetails);
                }
        }

        @VisibleForTesting
        public void setTxManager(PlatformTransactionManager theTxManager) {
                myTxManager = theTxManager;
        }

        private IBaseBundle batch(final RequestDetails theRequestDetails, IBaseBundle theRequest, boolean theNestedMode) {
                TransactionSemanticsHeader transactionSemantics = TransactionSemanticsHeader.DEFAULT;
                if (theRequestDetails != null) {
                        String transactionSemanticsString = theRequestDetails.getHeader("X-Transaction-Semantics");
                        if (transactionSemanticsString != null) {
                                transactionSemantics = TransactionSemanticsHeader.parse(transactionSemanticsString);
                        }
                }

                int totalAttempts = defaultIfNull(transactionSemantics.getRetryCount(), 0) + 1;
                boolean switchedToBatch = false;

                int minRetryDelay = getIfNull(transactionSemantics.getMinRetryDelay(), 0);
                int maxRetryDelay = getIfNull(transactionSemantics.getMaxRetryDelay(), 0);

                // Don't let the user request a crazy delay, this could be used
                // as a DOS attack
                maxRetryDelay = Math.max(maxRetryDelay, minRetryDelay);
                maxRetryDelay = Math.min(maxRetryDelay, 10000);
                totalAttempts = Math.min(totalAttempts, 5);

                IBaseBundle response;
                for (int i = 1; ; i++) {
                        try {
                                if (i < totalAttempts && transactionSemantics.isTryBatchAsTransactionFirst()) {
                                        BundleUtil.setBundleType(myContext, theRequest, "transaction");
                                        response = processTransaction(
                                                        theRequestDetails, new TransactionDetails(), theRequest, "Transaction", theNestedMode);
                                } else {
                                        BundleUtil.setBundleType(myContext, theRequest, "batch");
                                        response = processBatch(theRequestDetails, theRequest, theNestedMode);
                                }
                                break;
                        } catch (BaseServerResponseException e) {
                                if (i >= totalAttempts || theNestedMode) {
                                        throw e;
                                }

                                long delay = RandomUtils.insecure().randomLong(minRetryDelay, maxRetryDelay);
                                String sleepMessage = "";
                                if (delay > 0) {
                                        sleepMessage = "Sleeping for " + delay + " ms. ";
                                }

                                String switchedToBatchMessage = "";
                                if (switchedToBatch) {
                                        switchedToBatchMessage = " (as batch)";
                                }

                                String switchingToBatchMessage = "";
                                if (i + 1 == totalAttempts && transactionSemantics.isTryBatchAsTransactionFirst()) {
                                        switchingToBatchMessage = "Performing final retry using batch semantics. ";
                                        switchedToBatch = true;
                                        BundleUtil.setBundleType(myContext, theRequest, "batch");
                                }

                                ourLog.warn(
                                                "Transaction processing attempt{} {}/{} failed. {}{}",
                                                switchedToBatchMessage,
                                                i,
                                                totalAttempts,
                                                sleepMessage,
                                                switchingToBatchMessage);

                                if (delay > 0) {
                                        ThreadUtils.sleepQuietly(Duration.ofMillis(delay));
                                }
                        }
                }

                return response;
        }

        private IBaseBundle processBatch(RequestDetails theRequestDetails, IBaseBundle theRequest, boolean theNestedMode) {
                ourLog.info(
                                "Beginning batch with {} resources",
                                myVersionAdapter.getEntries(theRequest).size());

                long start = System.currentTimeMillis();

                IBaseBundle response =
                                myVersionAdapter.createBundle(org.hl7.fhir.r4.model.Bundle.BundleType.BATCHRESPONSE.toCode());
                Map<Integer, Object> responseMap = new ConcurrentHashMap<>();

                List<IBase> requestEntries = myVersionAdapter.getEntries(theRequest);
                int requestEntriesSize = requestEntries.size();

                // Now, run all non-gets sequentially, and all gets are submitted to the executor to run (potentially) in
                // parallel
                // The result is kept in the map to save the original position
                List<RetriableBundleTask> getCalls = new ArrayList<>();
                List<RetriableBundleTask> nonGetCalls = new ArrayList<>();

                CountDownLatch completionLatch = new CountDownLatch(requestEntriesSize);
                for (int i = 0; i < requestEntriesSize; i++) {
                        IBase nextRequestEntry = requestEntries.get(i);
                        RetriableBundleTask retriableBundleTask = new RetriableBundleTask(
                                        completionLatch, theRequestDetails, responseMap, i, nextRequestEntry, theNestedMode);
                        if (myVersionAdapter
                                        .getEntryRequestVerb(myContext, nextRequestEntry)
                                        .equalsIgnoreCase("GET")) {
                                getCalls.add(retriableBundleTask);
                        } else {
                                nonGetCalls.add(retriableBundleTask);
                        }
                }
                // Execute all non-gets on calling thread.
                nonGetCalls.forEach(RetriableBundleTask::run);
                // Execute all gets (potentially in a pool)
                if (myStorageSettings.getBundleBatchPoolSize() == 1) {
                        getCalls.forEach(RetriableBundleTask::run);
                } else {
                        getCalls.forEach(getCall -> getTaskExecutor().execute(getCall));
                }

                // waiting for all async tasks to be completed
                AsyncUtil.awaitLatchAndIgnoreInterrupt(completionLatch, 300L, TimeUnit.SECONDS);

                // Now, create the bundle response in original order
                Object nextResponseEntry;
                for (int i = 0; i < requestEntriesSize; i++) {

                        nextResponseEntry = responseMap.get(i);
                        if (nextResponseEntry instanceof ServerResponseExceptionHolder) {
                                ServerResponseExceptionHolder caughtEx = (ServerResponseExceptionHolder) nextResponseEntry;
                                if (caughtEx.getException() != null) {
                                        IBase nextEntry = myVersionAdapter.addEntry(response);
                                        populateEntryWithOperationOutcome(caughtEx.getException(), nextEntry);
                                        myVersionAdapter.setResponseStatus(
                                                        nextEntry, toStatusString(caughtEx.getException().getStatusCode()));
                                }
                        } else {
                                myVersionAdapter.addEntry(response, (IBase) nextResponseEntry);
                        }
                }

                long delay = System.currentTimeMillis() - start;
                ourLog.info("Batch completed in {}ms", delay);

                return response;
        }

        @VisibleForTesting
        public void setHapiTransactionService(HapiTransactionService theHapiTransactionService) {
                myHapiTransactionService = theHapiTransactionService;
        }

        private IBaseBundle processTransaction(
                        final RequestDetails theRequestDetails,
                        final TransactionDetails theTransactionDetails,
                        final IBaseBundle theRequest,
                        final String theActionName,
                        boolean theNestedMode) {
                validateDependencies();

                String transactionType = myVersionAdapter.getBundleType(theRequest);

                if (org.hl7.fhir.r4.model.Bundle.BundleType.BATCH.toCode().equals(transactionType)) {
                        return batch(theRequestDetails, theRequest, theNestedMode);
                }

                if (transactionType == null) {
                        String message = "Transaction Bundle did not specify valid Bundle.type, assuming "
                                        + Bundle.BundleType.TRANSACTION.toCode();
                        ourLog.warn(message);
                        transactionType = org.hl7.fhir.r4.model.Bundle.BundleType.TRANSACTION.toCode();
                }
                if (!org.hl7.fhir.r4.model.Bundle.BundleType.TRANSACTION.toCode().equals(transactionType)) {
                        throw new InvalidRequestException(
                                        Msg.code(527) + "Unable to process transaction where incoming Bundle.type = " + transactionType);
                }

                // Make a copy of the list because it gets sorted below, and we don't want to
                // modify the original Bundle
                List<IBase> requestEntries = new ArrayList<>(myVersionAdapter.getEntries(theRequest));
                int numberOfEntries = requestEntries.size();

                if (myStorageSettings.getMaximumTransactionBundleSize() != null
                                && numberOfEntries > myStorageSettings.getMaximumTransactionBundleSize()) {
                        throw new PayloadTooLargeException(
                                        Msg.code(528) + "Transaction Bundle Too large.  Transaction bundle contains " + numberOfEntries
                                                        + " which exceedes the maximum permitted transaction bundle size of "
                                                        + myStorageSettings.getMaximumTransactionBundleSize());
                }

                ourLog.debug("Beginning {} with {} resources", theActionName, numberOfEntries);

                theTransactionDetails.setFhirTransaction(true);
                final StopWatch transactionStopWatch = new StopWatch();

                // Do all entries have a verb?
                for (int i = 0; i < numberOfEntries; i++) {
                        IBase nextReqEntry = requestEntries.get(i);
                        String verb = myVersionAdapter.getEntryRequestVerb(myContext, nextReqEntry);
                        if (verb == null || !isValidVerb(verb)) {
                                throw new InvalidRequestException(Msg.code(529)
                                                + myContext
                                                                .getLocalizer()
                                                                .getMessage(BaseStorageDao.class, "transactionEntryHasInvalidVerb", verb, i));
                        }
                }

                /*
                 * We want to execute the transaction request bundle elements in the order
                 * specified by the FHIR specification (see TransactionSorter) so we save the
                 * original order in the request, then sort it.
                 *
                 * Entries with a type of GET are removed from the bundle so that they
                 * can be processed at the very end. We do this because the incoming resources
                 * are saved in a two-phase way in order to deal with interdependencies, and
                 * we want the GET processing to use the final indexing state
                 */
                final IBaseBundle response =
                                myVersionAdapter.createBundle(org.hl7.fhir.r4.model.Bundle.BundleType.TRANSACTIONRESPONSE.toCode());
                List<IBase> getEntries = new ArrayList<>();
                final IdentityHashMap<IBase, Integer> originalRequestOrder = new IdentityHashMap<>();
                for (int i = 0; i < requestEntries.size(); i++) {
                        IBase requestEntry = requestEntries.get(i);

                        originalRequestOrder.put(requestEntry, i);
                        myVersionAdapter.addEntry(response);
                        if (myVersionAdapter.getEntryRequestVerb(myContext, requestEntry).equals("GET")) {
                                getEntries.add(requestEntry);
                        }
                }

                /*
                 * See FhirSystemDaoDstu3Test#testTransactionWithPlaceholderIdInMatchUrl
                 * Basically if the resource has a match URL that references a placeholder,
                 * we try to handle the resource with the placeholder first.
                 */
                Set<String> placeholderIds = new HashSet<>();
                for (IBase nextEntry : requestEntries) {
                        String fullUrl = myVersionAdapter.getFullUrl(nextEntry);
                        if (isNotBlank(fullUrl) && fullUrl.startsWith(URN_PREFIX)) {
                                placeholderIds.add(fullUrl);
                        }
                }
                requestEntries.sort(new TransactionSorter(placeholderIds));

                // perform all writes
                prepareThenExecuteTransactionWriteOperations(
                                theRequestDetails,
                                theActionName,
                                theTransactionDetails,
                                transactionStopWatch,
                                response,
                                originalRequestOrder,
                                requestEntries);

                // perform all gets
                // (we do these last so that the gets happen on the final state of the DB;
                // see above note)
                doTransactionReadOperations(
                                theRequestDetails, response, getEntries, originalRequestOrder, transactionStopWatch, theNestedMode);

                // Interceptor broadcast: JPA_PERFTRACE_INFO
                IInterceptorBroadcaster compositeBroadcaster =
                                CompositeInterceptorBroadcaster.newCompositeBroadcaster(myInterceptorBroadcaster, theRequestDetails);
                if (compositeBroadcaster.hasHooks(Pointcut.JPA_PERFTRACE_INFO)) {
                        String taskDurations = transactionStopWatch.formatTaskDurations();
                        StorageProcessingMessage message = new StorageProcessingMessage();
                        message.setMessage("Transaction timing:\n" + taskDurations);
                        HookParams params = new HookParams()
                                        .add(RequestDetails.class, theRequestDetails)
                                        .addIfMatchesType(ServletRequestDetails.class, theRequestDetails)
                                        .add(StorageProcessingMessage.class, message);
                        compositeBroadcaster.callHooks(Pointcut.JPA_PERFTRACE_INFO, params);
                }

                return response;
        }

        @SuppressWarnings("unchecked")
        private void doTransactionReadOperations(
                        final RequestDetails theRequestDetails,
                        IBaseBundle theResponse,
                        List<IBase> theGetEntries,
                        IdentityHashMap<IBase, Integer> theOriginalRequestOrder,
                        StopWatch theTransactionStopWatch,
                        boolean theNestedMode) {
                if (theGetEntries.size() > 0) {
                        theTransactionStopWatch.startTask("Process " + theGetEntries.size() + " GET entries");

                        /*
                         * Loop through the request and process any entries of type GET
                         */
                        for (IBase nextReqEntry : theGetEntries) {
                                if (theNestedMode) {
                                        throw new InvalidRequestException(
                                                        Msg.code(530) + "Can not invoke read operation on nested transaction");
                                }

                                if (!(theRequestDetails instanceof ServletRequestDetails)) {
                                        throw new MethodNotAllowedException(
                                                        Msg.code(531) + "Can not call transaction GET methods from this context");
                                }

                                ServletRequestDetails srd = (ServletRequestDetails) theRequestDetails;
                                Integer originalOrder = theOriginalRequestOrder.get(nextReqEntry);
                                IBase nextRespEntry =
                                                (IBase) myVersionAdapter.getEntries(theResponse).get(originalOrder);

                                ArrayListMultimap<String, String> paramValues = ArrayListMultimap.create();
                                ServletSubRequestDetails requestDetailsForEntry =
                                                createRequestDetailsForReadEntry(srd, nextReqEntry, paramValues);

                                String url = requestDetailsForEntry.getRequestPath();

                                BaseMethodBinding method = srd.getServer().determineResourceMethod(requestDetailsForEntry, url);
                                if (method == null) {
                                        throw new IllegalArgumentException(Msg.code(532) + "Unable to handle GET " + url);
                                }

                                Validate.isTrue(method instanceof BaseResourceReturningMethodBinding, "Unable to handle GET {}", url);
                                try {
                                        BaseResourceReturningMethodBinding methodBinding = (BaseResourceReturningMethodBinding) method;
                                        requestDetailsForEntry.setRestOperationType(methodBinding.getRestOperationType());

                                        IBaseResource resource = methodBinding.doInvokeServer(srd.getServer(), requestDetailsForEntry);
                                        if (paramValues.containsKey(Constants.PARAM_SUMMARY)
                                                        || paramValues.containsKey(Constants.PARAM_CONTENT)) {
                                                resource = filterNestedBundle(requestDetailsForEntry, resource);
                                        }
                                        myVersionAdapter.setResource(nextRespEntry, resource);
                                        myVersionAdapter.setResponseStatus(nextRespEntry, toStatusString(Constants.STATUS_HTTP_200_OK));
                                } catch (NotModifiedException e) {
                                        myVersionAdapter.setResponseStatus(
                                                        nextRespEntry, toStatusString(Constants.STATUS_HTTP_304_NOT_MODIFIED));
                                } catch (BaseServerResponseException e) {
                                        ourLog.info("Failure processing transaction GET {}: {}", url, e.toString());
                                        myVersionAdapter.setResponseStatus(nextRespEntry, toStatusString(e.getStatusCode()));
                                        populateEntryWithOperationOutcome(e, nextRespEntry);
                                }
                        }
                        theTransactionStopWatch.endCurrentTask();
                }
        }

        /**
         * Checks if the given request entry has the extension specified to override the partition ids to use when processing that entry.
         * If the extension is present, this method will set the partition ids header in the given request details.
         */
        private void setRequestPartitionHeaderIfEntryHasTheExtension(IBase theReqEntry, RequestDetails theRequestDetails) {
                Optional<IBaseExtension<?, ?>> partitionIdsExtensionOptional =
                                myVersionAdapter.getEntryRequestExtensionByUrl(theReqEntry, EXTENSION_TRANSACTION_ENTRY_PARTITION_IDS);
                if (partitionIdsExtensionOptional.isPresent()
                                && partitionIdsExtensionOptional.get().getValue() instanceof IPrimitiveType<?>) {
                        IPrimitiveType<?> valueAsPrimitiveType =
                                        (IPrimitiveType<?>) partitionIdsExtensionOptional.get().getValue();
                        String value = valueAsPrimitiveType.getValueAsString();
                        theRequestDetails.setHeaders(Constants.HEADER_X_REQUEST_PARTITION_IDS, List.of(value));
                }
        }

        /**
         * Creates a new RequestDetails object based on the given RequestDetails. The new RequestDetails is to be used
         * when processing a write entry.
         * If the entry.request has the extension to override the partition ids, this method
         * sets the partition ids header in the newly created request details with the values from extension.
         * This allows using different partitions for different entries in the same transaction.
         *
         * @return the newly created request details
         */
        private RequestDetails createRequestDetailsForWriteEntry(
                        RequestDetails theRequestDetails, IBase theEntry, String theUrl, String theVerb) {

                if (theRequestDetails == null) {
                        ourLog.warn(
                                        "The RequestDetails passed in to the transaction is null. Cannot create a new RequestDetails for transaction entry.");
                        return null;
                }

                RequestDetails newRequestDetails;
                if (theRequestDetails instanceof ServletRequestDetails) {
                        newRequestDetails = ServletRequestUtil.getServletSubRequestDetails(
                                        (ServletRequestDetails) theRequestDetails, theUrl, theVerb, ArrayListMultimap.create());
                } else if (theRequestDetails instanceof SystemRequestDetails) {
                        newRequestDetails = new SystemRequestDetails((SystemRequestDetails) theRequestDetails);
                } else {
                        // RequestDetails is not a ServletRequestDetails or SystemRequestDetails, and I don't know how to properly
                        // clone such a RequestDetails. Use the original RequestDetails without making any entry specific
                        // modifications
                        ourLog.warn(
                                        "Cannot create a new RequestDetails for transaction entry out of the existing RequestDetails which is of type '{}'"
                                                        + "Using the original RequestDetails for transaction entries without any entry specific modifications.",
                                        theRequestDetails.getClass().getSimpleName());
                        return theRequestDetails;
                }
                setRequestPartitionHeaderIfEntryHasTheExtension(theEntry, newRequestDetails);
                return newRequestDetails;
        }

        /**
         * Creates a new RequestDetails based on the given one. The returned RequestDetails is to be used when processing
         * a GET entry of transaction.
         * It sets the headers in the newly request details according to the information from entry.request if needed.
         * Currently, GET entries only support ServletRequestDetails so it handles only that type.
         */
        private ServletSubRequestDetails createRequestDetailsForReadEntry(
                        ServletRequestDetails theRequestDetails, IBase theEntry, ArrayListMultimap<String, String> theParamValues) {

                final String verb = "GET";
                String transactionUrl = extractTransactionUrlOrThrowException(theEntry, verb);

                ServletSubRequestDetails subRequestDetails =
                                ServletRequestUtil.getServletSubRequestDetails(theRequestDetails, transactionUrl, verb, theParamValues);

                if (isNotBlank(myVersionAdapter.getEntryRequestIfMatch(theEntry))) {
                        subRequestDetails.addHeader(Constants.HEADER_IF_MATCH, myVersionAdapter.getEntryRequestIfMatch(theEntry));
                }
                if (isNotBlank(myVersionAdapter.getEntryRequestIfNoneExist(theEntry))) {
                        subRequestDetails.addHeader(
                                        Constants.HEADER_IF_NONE_EXIST, myVersionAdapter.getEntryRequestIfNoneExist(theEntry));
                }
                if (isNotBlank(myVersionAdapter.getEntryRequestIfNoneMatch(theEntry))) {
                        subRequestDetails.addHeader(
                                        Constants.HEADER_IF_NONE_MATCH, myVersionAdapter.getEntryRequestIfNoneMatch(theEntry));
                }

                setRequestPartitionHeaderIfEntryHasTheExtension(theEntry, subRequestDetails);

                return subRequestDetails;
        }

        /**
         * All of the write operations in the transaction (PUT, POST, etc.. basically anything
         * except GET) are performed in their own database transaction before we do the reads.
         * We do this because the reads (specifically the searches) often spawn their own
         * secondary database transaction and if we allow that within the primary
         * database transaction we can end up with deadlocks if the server is under
         * heavy load with lots of concurrent transactions using all available
         * database connections.
         */
        @SuppressWarnings("unchecked")
        private void prepareThenExecuteTransactionWriteOperations(
                        RequestDetails theRequestDetails,
                        String theActionName,
                        TransactionDetails theTransactionDetails,
                        StopWatch theTransactionStopWatch,
                        IBaseBundle theResponse,
                        IdentityHashMap<IBase, Integer> theOriginalRequestOrder,
                        List<IBase> theEntries) {

                TransactionWriteOperationsDetails writeOperationsDetails = null;
                if (haveWriteOperationsHooks(theRequestDetails)) {
                        writeOperationsDetails = buildWriteOperationsDetails(theEntries);
                        callWriteOperationsHook(
                                        Pointcut.STORAGE_TRANSACTION_WRITE_OPERATIONS_PRE,
                                        theRequestDetails,
                                        theTransactionDetails,
                                        writeOperationsDetails);
                }

                TransactionCallback<EntriesToProcessMap> txCallback = status -> {
                        final Set<IIdType> allIds = new LinkedHashSet<>();
                        final IdSubstitutionMap idSubstitutions = new IdSubstitutionMap();
                        final Map<IIdType, DaoMethodOutcome> idToPersistedOutcome = new LinkedHashMap<>();

                        EntriesToProcessMap retVal = doTransactionWriteOperations(
                                        theRequestDetails,
                                        theActionName,
                                        theTransactionDetails,
                                        allIds,
                                        idSubstitutions,
                                        idToPersistedOutcome,
                                        theResponse,
                                        theOriginalRequestOrder,
                                        theEntries,
                                        theTransactionStopWatch);

                        theTransactionStopWatch.startTask("Commit writes to database");
                        return retVal;
                };
                EntriesToProcessMap entriesToProcess;

                RequestPartitionId requestPartitionId =
                                determineRequestPartitionIdForWriteEntries(theRequestDetails, theTransactionDetails, theEntries);

                try {
                        entriesToProcess = myHapiTransactionService
                                        .withRequest(theRequestDetails)
                                        .withRequestPartitionId(requestPartitionId)
                                        .withTransactionDetails(theTransactionDetails)
                                        .execute(txCallback);
                } finally {
                        if (haveWriteOperationsHooks(theRequestDetails)) {
                                callWriteOperationsHook(
                                                Pointcut.STORAGE_TRANSACTION_WRITE_OPERATIONS_POST,
                                                theRequestDetails,
                                                theTransactionDetails,
                                                writeOperationsDetails);
                        }
                }

                theTransactionStopWatch.endCurrentTask();

                for (Map.Entry<IBase, IIdType> nextEntry : entriesToProcess.entrySet()) {
                        String responseLocation = nextEntry.getValue().toUnqualified().getValue();
                        String responseEtag = nextEntry.getValue().getVersionIdPart();
                        myVersionAdapter.setResponseLocation(nextEntry.getKey(), responseLocation);
                        myVersionAdapter.setResponseETag(nextEntry.getKey(), responseEtag);
                }
        }

        /**
         * This method looks at the FHIR actions being performed in a List of bundle entries,
         * and determines the associated request partitions.
         */
        @Nullable
        protected RequestPartitionId determineRequestPartitionIdForWriteEntries(
                        RequestDetails theRequestDetails, TransactionDetails theTransactionDetails, List<IBase> theEntries) {
                if (!myPartitionSettings.isPartitioningEnabled()) {
                        return RequestPartitionId.allPartitions();
                }

                return theEntries.stream()
                                .map(e -> getEntryRequestPartitionId(theRequestDetails, theTransactionDetails, e))
                                .reduce(null, (accumulator, nextPartition) -> {
                                        if (accumulator == null) {
                                                return nextPartition;
                                        } else if (nextPartition == null) {
                                                return accumulator;
                                        } else if (myHapiTransactionService.isCompatiblePartition(accumulator, nextPartition)) {
                                                return accumulator.mergeIds(nextPartition);
                                        } else if (!nextPartition.isAllPartitions()) {
                                                String msg = myContext
                                                                .getLocalizer()
                                                                .getMessage(
                                                                                BaseTransactionProcessor.class, "multiplePartitionAccesses", theEntries.size());
                                                throw new InvalidRequestException(Msg.code(2541) + msg);
                                        } else {
                                                return accumulator;
                                        }
                                });
        }

        @Nullable
        private RequestPartitionId getEntryRequestPartitionId(
                        RequestDetails theRequestDetails, TransactionDetails theTransactionDetails, IBase theEntry) {

                RequestPartitionId nextWriteEntryRequestPartitionId = null;
                String verb = myVersionAdapter.getEntryRequestVerb(myContext, theEntry);
                String url = extractTransactionUrlOrThrowException(theEntry, verb);
                RequestDetails requestDetailsForEntry =
                                createRequestDetailsForWriteEntry(theRequestDetails, theEntry, url, verb);
                if (isNotBlank(verb)) {
                        BundleEntryTransactionMethodEnum verbEnum = BundleEntryTransactionMethodEnum.valueOf(verb);
                        switch (verbEnum) {
                                case GET:
                                        nextWriteEntryRequestPartitionId = null;
                                        break;
                                case DELETE: {
                                        String requestUrl = myVersionAdapter.getEntryRequestUrl(theEntry);
                                        if (isNotBlank(requestUrl)) {
                                                IdType id = new IdType(requestUrl);
                                                String resourceType = id.getResourceType();
                                                ReadPartitionIdRequestDetails details =
                                                                ReadPartitionIdRequestDetails.forDelete(resourceType, id);
                                                nextWriteEntryRequestPartitionId =
                                                                myRequestPartitionHelperService.determineReadPartitionForRequest(
                                                                                requestDetailsForEntry, details);
                                        }
                                        break;
                                }
                                case PATCH: {
                                        String requestUrl = myVersionAdapter.getEntryRequestUrl(theEntry);
                                        if (isNotBlank(requestUrl)) {
                                                IdType id = new IdType(requestUrl);
                                                String resourceType = id.getResourceType();
                                                ReadPartitionIdRequestDetails details =
                                                                ReadPartitionIdRequestDetails.forPatch(resourceType, id);
                                                nextWriteEntryRequestPartitionId =
                                                                myRequestPartitionHelperService.determineReadPartitionForRequest(
                                                                                requestDetailsForEntry, details);
                                        }
                                        break;
                                }
                                case POST: {
                                        IBaseResource resource = myVersionAdapter.getResource(theEntry);
                                        String resourceType = myContext.getResourceType(resource);
                                        nextWriteEntryRequestPartitionId =
                                                        myRequestPartitionHelperService.determineCreatePartitionForRequest(
                                                                        requestDetailsForEntry, resource, resourceType);
                                        break;
                                }
                                case PUT: {
                                        IBaseResource resource = myVersionAdapter.getResource(theEntry);
                                        if (resource != null) {
                                                String resourceType = myContext.getResourceType(resource);
                                                String resourceId = null;
                                                if (resource.getIdElement().hasIdPart()) {
                                                        resourceId =
                                                                        resourceType + "/" + resource.getIdElement().getIdPart();
                                                }
                                                if (resourceId != null) {
                                                        nextWriteEntryRequestPartitionId = theTransactionDetails.getResolvedPartition(resourceId);
                                                }
                                                if (nextWriteEntryRequestPartitionId == null) {
                                                        nextWriteEntryRequestPartitionId =
                                                                        myRequestPartitionHelperService.determineCreatePartitionForRequest(
                                                                                        requestDetailsForEntry, resource, resourceType);
                                                        if (resourceId != null) {
                                                                theTransactionDetails.addResolvedPartition(
                                                                                resourceId, nextWriteEntryRequestPartitionId);
                                                        }
                                                }
                                        }
                                        break;
                                }
                        }
                }
                return nextWriteEntryRequestPartitionId;
        }

        private boolean haveWriteOperationsHooks(RequestDetails theRequestDetails) {
                IInterceptorBroadcaster compositeBroadcaster =
                                CompositeInterceptorBroadcaster.newCompositeBroadcaster(myInterceptorBroadcaster, theRequestDetails);
                return compositeBroadcaster.hasHooks(Pointcut.STORAGE_TRANSACTION_WRITE_OPERATIONS_PRE)
                                || compositeBroadcaster.hasHooks(Pointcut.STORAGE_TRANSACTION_WRITE_OPERATIONS_POST);
        }

        private void callWriteOperationsHook(
                        Pointcut thePointcut,
                        RequestDetails theRequestDetails,
                        TransactionDetails theTransactionDetails,
                        TransactionWriteOperationsDetails theWriteOperationsDetails) {
                IInterceptorBroadcaster compositeBroadcaster =
                                CompositeInterceptorBroadcaster.newCompositeBroadcaster(myInterceptorBroadcaster, theRequestDetails);
                if (compositeBroadcaster.hasHooks(thePointcut)) {
                        HookParams params = new HookParams()
                                        .add(TransactionDetails.class, theTransactionDetails)
                                        .add(TransactionWriteOperationsDetails.class, theWriteOperationsDetails);
                        compositeBroadcaster.callHooks(thePointcut, params);
                }
        }

        @SuppressWarnings("unchecked")
        private TransactionWriteOperationsDetails buildWriteOperationsDetails(List<IBase> theEntries) {
                TransactionWriteOperationsDetails writeOperationsDetails;
                List<String> updateRequestUrls = new ArrayList<>();
                List<String> conditionalCreateRequestUrls = new ArrayList<>();
                // Extract
                for (IBase nextEntry : theEntries) {
                        String method = myVersionAdapter.getEntryRequestVerb(myContext, nextEntry);
                        if ("PUT".equals(method)) {
                                String requestUrl = myVersionAdapter.getEntryRequestUrl(nextEntry);
                                if (isNotBlank(requestUrl)) {
                                        updateRequestUrls.add(requestUrl);
                                }
                        } else if ("POST".equals(method)) {
                                String requestUrl = myVersionAdapter.getEntryRequestIfNoneExist(nextEntry);
                                if (isNotBlank(requestUrl) && requestUrl.contains("?")) {
                                        conditionalCreateRequestUrls.add(requestUrl);
                                }
                        }
                }

                writeOperationsDetails = new TransactionWriteOperationsDetails();
                writeOperationsDetails.setUpdateRequestUrls(updateRequestUrls);
                writeOperationsDetails.setConditionalCreateRequestUrls(conditionalCreateRequestUrls);
                return writeOperationsDetails;
        }

        private boolean isValidVerb(String theVerb) {
                try {
                        return org.hl7.fhir.r4.model.Bundle.HTTPVerb.fromCode(theVerb) != null;
                } catch (FHIRException theE) {
                        return false;
                }
        }

        /**
         * This method is called for nested bundles (e.g. if we received a transaction with an entry that
         * was a GET search, this method is called on the bundle for the search result, that will be placed in the
         * outer bundle). This method applies the _summary and _content parameters to the output of
         * that bundle.
         * <p>
         * TODO: This isn't the most efficient way of doing this.. hopefully we can come up with something better in the future.
         */
        private IBaseResource filterNestedBundle(RequestDetails theRequestDetails, IBaseResource theResource) {
                IParser p = myContext.newJsonParser();
                RestfulServerUtils.configureResponseParser(theRequestDetails, p);
                return p.parseResource(theResource.getClass(), p.encodeResourceToString(theResource));
        }

        protected void validateDependencies() {
                Validate.notNull(myContext);
                Validate.notNull(myTxManager);
        }

        private IIdType newIdType(String theValue) {
                return myContext.getVersion().newIdType().setValue(theValue);
        }

        /**
         * Searches for duplicate conditional creates and consolidates them.
         */
        @SuppressWarnings("unchecked")
        private void consolidateDuplicateConditionals(
                        RequestDetails theRequestDetails, String theActionName, List<IBase> theEntries) {
                final Set<String> keysWithNoFullUrl = new HashSet<>();
                final HashMap<String, String> keyToUuid = new HashMap<>();

                for (int index = 0, originalIndex = 0; index < theEntries.size(); index++, originalIndex++) {
                        IBase nextReqEntry = theEntries.get(index);
                        IBaseResource resource = myVersionAdapter.getResource(nextReqEntry);
                        if (resource != null) {
                                String verb = myVersionAdapter.getEntryRequestVerb(myContext, nextReqEntry);
                                String entryFullUrl = myVersionAdapter.getFullUrl(nextReqEntry);
                                String requestUrl = myVersionAdapter.getEntryRequestUrl(nextReqEntry);
                                String ifNoneExist = myVersionAdapter.getEntryRequestIfNoneExist(nextReqEntry);

                                // Conditional UPDATE
                                boolean consolidateEntryCandidate = false;
                                String conditionalUrl;
                                switch (verb) {
                                        case "PUT":
                                                conditionalUrl = requestUrl;
                                                if (isNotBlank(requestUrl)) {
                                                        int questionMarkIndex = requestUrl.indexOf('?');
                                                        if (questionMarkIndex >= 0 && requestUrl.length() > (questionMarkIndex + 1)) {
                                                                consolidateEntryCandidate = true;
                                                        }
                                                }
                                                break;

                                                // Conditional CREATE
                                        case "POST":
                                                conditionalUrl = ifNoneExist;
                                                if (isNotBlank(ifNoneExist)) {
                                                        if (isBlank(entryFullUrl) || !entryFullUrl.equals(requestUrl)) {
                                                                consolidateEntryCandidate = true;
                                                        }
                                                }
                                                break;

                                        default:
                                                continue;
                                }

                                if (isNotBlank(conditionalUrl) && !conditionalUrl.contains("?")) {
                                        conditionalUrl = myContext.getResourceType(resource) + "?" + conditionalUrl;
                                }

                                String key = verb + "|" + conditionalUrl;
                                if (consolidateEntryCandidate) {
                                        if (isBlank(entryFullUrl)) {
                                                if (isNotBlank(conditionalUrl)) {
                                                        if (!keysWithNoFullUrl.add(key)) {
                                                                throw new InvalidRequestException(Msg.code(2008) + "Unable to process " + theActionName
                                                                                + " - Request contains multiple anonymous entries (Bundle.entry.fullUrl not populated) with conditional URL: \""
                                                                                + UrlUtil.sanitizeUrlPart(conditionalUrl)
                                                                                + "\". Does transaction request contain duplicates?");
                                                        }
                                                }
                                        } else {
                                                if (!keyToUuid.containsKey(key)) {
                                                        keyToUuid.put(key, entryFullUrl);
                                                } else {
                                                        String msg = "Discarding transaction bundle entry " + originalIndex
                                                                        + " as it contained a duplicate conditional " + verb;
                                                        ourLog.info(msg);
                                                        // Interceptor broadcast: JPA_PERFTRACE_INFO
                                                        IInterceptorBroadcaster compositeBroadcaster =
                                                                        CompositeInterceptorBroadcaster.newCompositeBroadcaster(
                                                                                        myInterceptorBroadcaster, theRequestDetails);
                                                        if (compositeBroadcaster.hasHooks(Pointcut.JPA_PERFTRACE_WARNING)) {
                                                                StorageProcessingMessage message = new StorageProcessingMessage().setMessage(msg);
                                                                HookParams params = new HookParams()
                                                                                .add(RequestDetails.class, theRequestDetails)
                                                                                .addIfMatchesType(ServletRequestDetails.class, theRequestDetails)
                                                                                .add(StorageProcessingMessage.class, message);
                                                                compositeBroadcaster.callHooks(Pointcut.JPA_PERFTRACE_INFO, params);
                                                        }

                                                        theEntries.remove(index);
                                                        index--;
                                                        String existingUuid = keyToUuid.get(key);
                                                        replaceReferencesInEntriesWithConsolidatedUUID(theEntries, entryFullUrl, existingUuid);
                                                }
                                        }
                                }
                        }
                }
        }

        /**
         * Iterates over all entries, and if it finds any which have references which match the fullUrl of the entry that was consolidated out
         * replace them with our new consolidated UUID
         */
        private void replaceReferencesInEntriesWithConsolidatedUUID(
                        List<IBase> theEntries, String theEntryFullUrl, String existingUuid) {
                for (IBase nextEntry : theEntries) {
                        @SuppressWarnings("unchecked")
                        IBaseResource nextResource = myVersionAdapter.getResource(nextEntry);
                        if (nextResource != null) {
                                for (IBaseReference nextReference :
                                                myContext.newTerser().getAllPopulatedChildElementsOfType(nextResource, IBaseReference.class)) {
                                        // We're interested in any references directly to the placeholder ID, but also
                                        // references that have a resource target that has the placeholder ID.
                                        String nextReferenceId = nextReference.getReferenceElement().getValue();
                                        if (isBlank(nextReferenceId) && nextReference.getResource() != null) {
                                                nextReferenceId =
                                                                nextReference.getResource().getIdElement().getValue();
                                        }
                                        if (theEntryFullUrl.equals(nextReferenceId)) {
                                                nextReference.setReference(existingUuid);
                                                nextReference.setResource(null);
                                        }
                                }
                        }
                }
        }

        /**
         * Retrieves the next resource id (IIdType) from the base resource and next request entry.
         *
         * @param theBaseResource - base resource
         * @param theNextReqEntry - next request entry
         * @param theAllIds       - set of all IIdType values
         * @param theVerb
         * @return
         */
        private IIdType getNextResourceIdFromBaseResource(
                        IBaseResource theBaseResource, IBase theNextReqEntry, Set<IIdType> theAllIds, String theVerb) {
                IIdType nextResourceId = null;
                if (theBaseResource != null) {
                        nextResourceId = theBaseResource.getIdElement();

                        @SuppressWarnings("unchecked")
                        String fullUrl = myVersionAdapter.getFullUrl(theNextReqEntry);
                        if (isNotBlank(fullUrl)) {
                                IIdType fullUrlIdType = newIdType(fullUrl);
                                if (isPlaceholder(fullUrlIdType)) {
                                        nextResourceId = fullUrlIdType;
                                } else if (!nextResourceId.hasIdPart()) {
                                        nextResourceId = fullUrlIdType;
                                }
                        }

                        if (nextResourceId.hasIdPart() && !isPlaceholder(nextResourceId)) {
                                int colonIndex = nextResourceId.getIdPart().indexOf(':');
                                if (colonIndex != -1) {
                                        if (INVALID_PLACEHOLDER_PATTERN
                                                        .matcher(nextResourceId.getIdPart())
                                                        .matches()) {
                                                throw new InvalidRequestException(
                                                                Msg.code(533) + "Invalid placeholder ID found: " + nextResourceId.getIdPart()
                                                                                + " - Must be of the form 'urn:uuid:[uuid]' or 'urn:oid:[oid]'");
                                        }
                                }
                        }

                        if (nextResourceId.hasIdPart() && !nextResourceId.hasResourceType() && !isPlaceholder(nextResourceId)) {
                                nextResourceId = newIdType(toResourceName(theBaseResource.getClass()), nextResourceId.getIdPart());
                                theBaseResource.setId(nextResourceId);
                        }

                        /*
                         * Ensure that the bundle doesn't have any duplicates, since this causes all kinds of weirdness
                         */
                        if (isPlaceholder(nextResourceId)) {
                                if (!theAllIds.add(nextResourceId)) {
                                        throw new InvalidRequestException(Msg.code(534)
                                                        + myContext
                                                                        .getLocalizer()
                                                                        .getMessage(
                                                                                        BaseStorageDao.class,
                                                                                        "transactionContainsMultipleWithDuplicateId",
                                                                                        nextResourceId));
                                }
                        } else if (nextResourceId.hasResourceType() && nextResourceId.hasIdPart() && !"POST".equals(theVerb)) {
                                IIdType nextId = nextResourceId.toUnqualifiedVersionless();
                                if (!theAllIds.add(nextId)) {
                                        throw new InvalidRequestException(Msg.code(535)
                                                        + myContext
                                                                        .getLocalizer()
                                                                        .getMessage(
                                                                                        BaseStorageDao.class,
                                                                                        "transactionContainsMultipleWithDuplicateId",
                                                                                        nextId));
                                }
                        }
                }

                return nextResourceId;
        }

        /**
         * After pre-hooks have been called
         */
        @SuppressWarnings({"unchecked", "rawtypes"})
        protected EntriesToProcessMap doTransactionWriteOperations(
                        final RequestDetails theRequest,
                        String theActionName,
                        TransactionDetails theTransactionDetails,
                        Set<IIdType> theAllIds,
                        IdSubstitutionMap theIdSubstitutions,
                        Map<IIdType, DaoMethodOutcome> theIdToPersistedOutcome,
                        IBaseBundle theResponse,
                        IdentityHashMap<IBase, Integer> theOriginalRequestOrder,
                        List<IBase> theEntries,
                        StopWatch theTransactionStopWatch) {

                // During a transaction, we don't execute hooks, instead, we execute them all post-transaction.
                theTransactionDetails.beginAcceptingDeferredInterceptorBroadcasts(
                                Pointcut.STORAGE_PRECOMMIT_RESOURCE_CREATED,
                                Pointcut.STORAGE_PRECOMMIT_RESOURCE_UPDATED,
                                Pointcut.STORAGE_PRECOMMIT_RESOURCE_DELETED);
                try {
                        Set<String> deletedResources = new HashSet<>();
                        DeleteConflictList deleteConflicts = new DeleteConflictList();
                        EntriesToProcessMap entriesToProcess = new EntriesToProcessMap();
                        Set<IIdType> nonUpdatedEntities = new HashSet<>();
                        Set<IBasePersistedResource> updatedEntities = new HashSet<>();
                        Map<String, IIdType> conditionalUrlToIdMap = new HashMap<>();
                        List<IBaseResource> updatedResources = new ArrayList<>();
                        Map<String, Class<? extends IBaseResource>> conditionalRequestUrls = new HashMap<>();

                        /*
                         * Look for duplicate conditional creates and consolidate them
                         */
                        consolidateDuplicateConditionals(theRequest, theActionName, theEntries);

                        /*
                         * Loop through the request and process any entries of type
                         * PUT, POST or DELETE
                         */
                        String previousVerb = null;
                        for (int i = 0; i < theEntries.size(); i++) {
                                if (i % 250 == 0) {
                                        ourLog.debug("Processed {} non-GET entries out of {} in transaction", i, theEntries.size());
                                }

                                IBase nextReqEntry = theEntries.get(i);

                                String verb = myVersionAdapter.getEntryRequestVerb(myContext, nextReqEntry);

                                if (previousVerb != null && !previousVerb.equals(verb)) {
                                        handleVerbChangeInTransactionWriteOperations();
                                }
                                previousVerb = verb;
                                if ("GET".equals(verb)) {
                                        continue;
                                }

                                String url = extractAndVerifyTransactionUrlForEntry(nextReqEntry, verb);
                                RequestDetails requestDetailsForEntry =
                                                createRequestDetailsForWriteEntry(theRequest, nextReqEntry, url, verb);

                                IBaseResource res = myVersionAdapter.getResource(nextReqEntry);
                                IIdType nextResourceId = getNextResourceIdFromBaseResource(res, nextReqEntry, theAllIds, verb);

                                String resourceType = res != null ? myContext.getResourceType(res) : null;
                                Integer order = theOriginalRequestOrder.get(nextReqEntry);
                                IBase nextRespEntry =
                                                (IBase) myVersionAdapter.getEntries(theResponse).get(order);

                                theTransactionStopWatch.startTask(
                                                "Bundle.entry[" + i + "]: " + verb + " " + defaultString(resourceType));

                                if (res != null) {
                                        String previousResourceId = res.getIdElement().getValue();
                                        theTransactionDetails.addRollbackUndoAction(() -> res.setId(previousResourceId));
                                }

                                switch (verb) {
                                        case "POST": {
                                                // CREATE
                                                validateResourcePresent(res, order, verb);

                                                IFhirResourceDao resourceDao = getDaoOrThrowException(res.getClass());
                                                res.setId((String) null);

                                                DaoMethodOutcome outcome;
                                                String matchUrl = myVersionAdapter.getEntryRequestIfNoneExist(nextReqEntry);
                                                matchUrl = performIdSubstitutionsInMatchUrl(theIdSubstitutions, matchUrl);
                                                // create individual resource
                                                outcome =
                                                                resourceDao.create(res, matchUrl, false, requestDetailsForEntry, theTransactionDetails);
                                                setConditionalUrlToBeValidatedLater(conditionalUrlToIdMap, matchUrl, outcome.getId());
                                                res.setId(outcome.getId());

                                                if (nextResourceId != null) {
                                                        handleTransactionCreateOrUpdateOutcome(
                                                                        theIdSubstitutions,
                                                                        theIdToPersistedOutcome,
                                                                        nextResourceId,
                                                                        outcome,
                                                                        nextRespEntry,
                                                                        resourceType,
                                                                        res,
                                                                        requestDetailsForEntry);
                                                }
                                                entriesToProcess.put(nextRespEntry, outcome.getId(), nextRespEntry);
                                                theTransactionDetails.addResolvedResource(outcome.getId(), outcome::getResource);
                                                if (outcome.getCreated() == false) {
                                                        nonUpdatedEntities.add(outcome.getId());
                                                } else {
                                                        if (isNotBlank(matchUrl)) {
                                                                conditionalRequestUrls.put(matchUrl, res.getClass());
                                                        }
                                                }

                                                break;
                                        }
                                        case "DELETE": {
                                                // DELETE
                                                UrlUtil.UrlParts parts = UrlUtil.parseUrl(url);
                                                IFhirResourceDao<? extends IBaseResource> dao = toDao(parts, verb, url);
                                                int status = Constants.STATUS_HTTP_204_NO_CONTENT;
                                                if (parts.getResourceId() != null) {
                                                        IIdType deleteId = newIdType(parts.getResourceType(), parts.getResourceId());
                                                        if (!deletedResources.contains(deleteId.getValueAsString())) {
                                                                DaoMethodOutcome outcome = dao.delete(
                                                                                deleteId, deleteConflicts, requestDetailsForEntry, theTransactionDetails);
                                                                if (outcome.getEntity() != null) {
                                                                        deletedResources.add(deleteId.getValueAsString());
                                                                        entriesToProcess.put(nextRespEntry, outcome.getId(), nextRespEntry);
                                                                }
                                                                myVersionAdapter.setResponseOutcome(nextRespEntry, outcome.getOperationOutcome());
                                                        }
                                                } else {
                                                        String matchUrl = parts.getResourceType() + '?' + parts.getParams();
                                                        matchUrl = performIdSubstitutionsInMatchUrl(theIdSubstitutions, matchUrl);
                                                        DeleteMethodOutcome deleteOutcome = dao.deleteByUrl(
                                                                        matchUrl, deleteConflicts, requestDetailsForEntry, theTransactionDetails);
                                                        setConditionalUrlToBeValidatedLater(conditionalUrlToIdMap, matchUrl, deleteOutcome.getId());
                                                        List<? extends IBasePersistedResource> allDeleted = deleteOutcome.getDeletedEntities();
                                                        for (IBasePersistedResource deleted : allDeleted) {
                                                                deletedResources.add(deleted.getIdDt()
                                                                                .toUnqualifiedVersionless()
                                                                                .getValueAsString());
                                                        }
                                                        if (allDeleted.isEmpty()) {
                                                                status = Constants.STATUS_HTTP_204_NO_CONTENT;
                                                        }

                                                        myVersionAdapter.setResponseOutcome(nextRespEntry, deleteOutcome.getOperationOutcome());
                                                }

                                                myVersionAdapter.setResponseStatus(nextRespEntry, toStatusString(status));

                                                break;
                                        }
                                        case "PUT": {
                                                // UPDATE
                                                validateResourcePresent(res, order, verb);
                                                @SuppressWarnings("rawtypes")
                                                IFhirResourceDao resourceDao = getDaoOrThrowException(res.getClass());

                                                DaoMethodOutcome outcome;
                                                UrlUtil.UrlParts parts = UrlUtil.parseUrl(url);
                                                if (isNotBlank(parts.getResourceId())) {
                                                        String version = null;
                                                        if (isNotBlank(myVersionAdapter.getEntryRequestIfMatch(nextReqEntry))) {
                                                                version = ParameterUtil.parseETagValue(
                                                                                myVersionAdapter.getEntryRequestIfMatch(nextReqEntry));
                                                        }
                                                        res.setId(newIdType(parts.getResourceType(), parts.getResourceId(), version));
                                                        outcome = resourceDao.update(
                                                                        res, null, false, false, requestDetailsForEntry, theTransactionDetails);
                                                } else {
                                                        if (!shouldConditionalUpdateMatchId(theTransactionDetails, res.getIdElement())) {
                                                                res.setId((String) null);
                                                        }
                                                        String matchUrl;
                                                        if (isNotBlank(parts.getParams())) {
                                                                matchUrl = parts.getResourceType() + '?' + parts.getParams();
                                                        } else {
                                                                matchUrl = parts.getResourceType();
                                                        }
                                                        matchUrl = performIdSubstitutionsInMatchUrl(theIdSubstitutions, matchUrl);
                                                        outcome = resourceDao.update(
                                                                        res, matchUrl, false, false, requestDetailsForEntry, theTransactionDetails);
                                                        setConditionalUrlToBeValidatedLater(conditionalUrlToIdMap, matchUrl, outcome.getId());
                                                        if (Boolean.TRUE.equals(outcome.getCreated())) {
                                                                conditionalRequestUrls.put(matchUrl, res.getClass());
                                                        }
                                                }

                                                if (outcome.getCreated() == Boolean.FALSE
                                                                || (outcome.getCreated() == Boolean.TRUE
                                                                                && outcome.getId().getVersionIdPartAsLong() > 1)) {
                                                        updatedEntities.add(outcome.getEntity());
                                                        if (outcome.getResource() != null) {
                                                                updatedResources.add(outcome.getResource());
                                                        }
                                                }

                                                theTransactionDetails.addResolvedResource(outcome.getId(), outcome::getResource);
                                                handleTransactionCreateOrUpdateOutcome(
                                                                theIdSubstitutions,
                                                                theIdToPersistedOutcome,
                                                                nextResourceId,
                                                                outcome,
                                                                nextRespEntry,
                                                                resourceType,
                                                                res,
                                                                requestDetailsForEntry);
                                                entriesToProcess.put(nextRespEntry, outcome.getId(), nextRespEntry);
                                                break;
                                        }
                                        case "PATCH": {
                                                // PATCH
                                                validateResourcePresent(res, order, verb);

                                                UrlUtil.UrlParts parts = UrlUtil.parseUrl(url);

                                                String matchUrl = toMatchUrl(nextReqEntry);
                                                matchUrl = performIdSubstitutionsInMatchUrl(theIdSubstitutions, matchUrl);
                                                String patchBody = null;
                                                String contentType;
                                                IBaseParameters patchBodyParameters = null;
                                                PatchTypeEnum patchType = null;

                                                if (res instanceof IBaseBinary) {
                                                        IBaseBinary binary = (IBaseBinary) res;
                                                        if (binary.getContent() != null && binary.getContent().length > 0) {
                                                                patchBody = toUtf8String(binary.getContent());
                                                        }
                                                        contentType = binary.getContentType();
                                                        patchType =
                                                                        PatchTypeEnum.forContentTypeOrThrowInvalidRequestException(myContext, contentType);
                                                        if (patchType == PatchTypeEnum.FHIR_PATCH_JSON
                                                                        || patchType == PatchTypeEnum.FHIR_PATCH_XML) {
                                                                String msg = myContext
                                                                                .getLocalizer()
                                                                                .getMessage(
                                                                                                BaseTransactionProcessor.class, "fhirPatchShouldNotUseBinaryResource");
                                                                throw new InvalidRequestException(Msg.code(536) + msg);
                                                        }
                                                } else if (res instanceof IBaseParameters) {
                                                        patchBodyParameters = (IBaseParameters) res;
                                                        patchType = PatchTypeEnum.FHIR_PATCH_JSON;
                                                }

                                                if (patchBodyParameters == null) {
                                                        if (isBlank(patchBody)) {
                                                                String msg = myContext
                                                                                .getLocalizer()
                                                                                .getMessage(BaseTransactionProcessor.class, "missingPatchBody");
                                                                throw new InvalidRequestException(Msg.code(537) + msg);
                                                        }
                                                }

                                                IFhirResourceDao<? extends IBaseResource> dao = toDao(parts, verb, url);
                                                IIdType patchId =
                                                                myContext.getVersion().newIdType(parts.getResourceType(), parts.getResourceId());

                                                String conditionalUrl;
                                                if (isNull(patchId.getIdPart())) {
                                                        conditionalUrl = url;
                                                } else {
                                                        conditionalUrl = matchUrl;
                                                        String ifMatch = myVersionAdapter.getEntryRequestIfMatch(nextReqEntry);
                                                        if (isNotBlank(ifMatch)) {
                                                                patchId = UpdateMethodBinding.applyETagAsVersion(ifMatch, patchId);
                                                        }
                                                }

                                                DaoMethodOutcome outcome = dao.patchInTransaction(
                                                                patchId,
                                                                conditionalUrl,
                                                                false,
                                                                patchType,
                                                                patchBody,
                                                                patchBodyParameters,
                                                                requestDetailsForEntry,
                                                                theTransactionDetails);
                                                setConditionalUrlToBeValidatedLater(conditionalUrlToIdMap, matchUrl, outcome.getId());
                                                updatedEntities.add(outcome.getEntity());
                                                if (outcome.getResource() != null) {
                                                        updatedResources.add(outcome.getResource());
                                                }
                                                if (nextResourceId != null) {
                                                        handleTransactionCreateOrUpdateOutcome(
                                                                        theIdSubstitutions,
                                                                        theIdToPersistedOutcome,
                                                                        nextResourceId,
                                                                        outcome,
                                                                        nextRespEntry,
                                                                        resourceType,
                                                                        res,
                                                                        requestDetailsForEntry);
                                                }
                                                entriesToProcess.put(nextRespEntry, outcome.getId(), nextRespEntry);

                                                break;
                                        }
                                        case "GET":
                                                break;
                                        default:
                                                throw new InvalidRequestException(
                                                                Msg.code(538) + "Unable to handle verb in transaction: " + verb);
                                }

                                theTransactionStopWatch.endCurrentTask();
                        }

                        postTransactionProcess(theTransactionDetails);

                        /*
                         * Make sure that there are no conflicts from deletions. E.g. we can't delete something
                         * if something else has a reference to it.. Unless the thing that has a reference to it
                         * was also deleted as a part of this transaction, which is why we check this now at the
                         * end.
                         */
                        checkForDeleteConflicts(deleteConflicts, deletedResources, updatedResources);

                        theIdToPersistedOutcome.entrySet().forEach(idAndOutcome -> {
                                theTransactionDetails.addResolvedResourceId(
                                                idAndOutcome.getKey(), idAndOutcome.getValue().getPersistentId());
                        });

                        /*
                         * Perform ID substitutions and then index each resource we have saved
                         */

                        resolveReferencesThenSaveAndIndexResources(
                                        theRequest,
                                        theTransactionDetails,
                                        theIdSubstitutions,
                                        theIdToPersistedOutcome,
                                        theTransactionStopWatch,
                                        entriesToProcess,
                                        nonUpdatedEntities,
                                        updatedEntities);

                        theTransactionStopWatch.endCurrentTask();

                        // flush writes to db
                        theTransactionStopWatch.startTask("Flush writes to database");

                        // flush the changes
                        flushSession(theIdToPersistedOutcome);

                        theTransactionStopWatch.endCurrentTask();

                        /*
                         * Double check we didn't allow any duplicates we shouldn't have
                         */
                        if (conditionalRequestUrls.size() > 0) {
                                theTransactionStopWatch.startTask("Check for conflicts in conditional resources");
                        }
                        if (!myStorageSettings.isMassIngestionMode()) {
                                validateNoDuplicates(
                                                theRequest,
                                                theTransactionDetails,
                                                theActionName,
                                                conditionalRequestUrls,
                                                theIdToPersistedOutcome.values());
                        }

                        theTransactionStopWatch.endCurrentTask();
                        if (conditionalUrlToIdMap.size() > 0) {
                                theTransactionStopWatch.startTask(
                                                "Check that all conditionally created/updated entities actually match their conditionals.");
                        }

                        if (!myStorageSettings.isMassIngestionMode()) {
                                validateAllInsertsMatchTheirConditionalUrls(theIdToPersistedOutcome, conditionalUrlToIdMap, theRequest);
                        }
                        theTransactionStopWatch.endCurrentTask();

                        for (IIdType next : theAllIds) {
                                IIdType replacement = theIdSubstitutions.getForSource(next);
                                if (replacement != null && !replacement.equals(next)) {
                                        ourLog.debug(
                                                        "Placeholder resource ID \"{}\" was replaced with permanent ID \"{}\"", next, replacement);
                                }
                        }

                        IInterceptorBroadcaster compositeBroadcaster =
                                        CompositeInterceptorBroadcaster.newCompositeBroadcaster(myInterceptorBroadcaster, theRequest);
                        ListMultimap<Pointcut, HookParams> deferredBroadcastEvents =
                                        theTransactionDetails.endAcceptingDeferredInterceptorBroadcasts();
                        for (Map.Entry<Pointcut, HookParams> nextEntry : deferredBroadcastEvents.entries()) {
                                Pointcut nextPointcut = nextEntry.getKey();
                                HookParams nextParams = nextEntry.getValue();
                                compositeBroadcaster.callHooks(nextPointcut, nextParams);
                        }

                        DeferredInterceptorBroadcasts deferredInterceptorBroadcasts =
                                        new DeferredInterceptorBroadcasts(deferredBroadcastEvents);
                        HookParams params = new HookParams()
                                        .add(RequestDetails.class, theRequest)
                                        .addIfMatchesType(ServletRequestDetails.class, theRequest)
                                        .add(DeferredInterceptorBroadcasts.class, deferredInterceptorBroadcasts)
                                        .add(TransactionDetails.class, theTransactionDetails)
                                        .add(IBaseBundle.class, theResponse);
                        compositeBroadcaster.callHooks(Pointcut.STORAGE_TRANSACTION_PROCESSED, params);

                        theTransactionDetails.deferredBroadcastProcessingFinished();

                        // finishedCallingDeferredInterceptorBroadcasts

                        return entriesToProcess;

                } finally {
                        if (theTransactionDetails.isAcceptingDeferredInterceptorBroadcasts()) {
                                theTransactionDetails.endAcceptingDeferredInterceptorBroadcasts();
                        }
                }
        }

        /**
         * Subclasses may override this in order to invoke specific operations when
         * we're finished handling all the write entries in the transaction bundle
         * with a given verb.
         */
        protected void handleVerbChangeInTransactionWriteOperations() {
                // nothing
        }

        /**
         * Implement to handle post transaction processing
         */
        protected void postTransactionProcess(TransactionDetails theTransactionDetails) {
                // nothing
        }

        /**
         * Check for if a resource id should be matched in a conditional update
         * If the FHIR version is older than R4, it follows the old specifications and does not match
         * If the resource id has been resolved, then it is an existing resource and does not need to be matched
         * If the resource id is local or a placeholder, the id is temporary and should not be matched
         */
        private boolean shouldConditionalUpdateMatchId(TransactionDetails theTransactionDetails, IIdType theId) {
                if (myContext.getVersion().getVersion().isOlderThan(FhirVersionEnum.R4)) {
                        return false;
                }
                if (theTransactionDetails.hasResolvedResourceId(theId)
                                && !theTransactionDetails.isResolvedResourceIdEmpty(theId)) {
                        return false;
                }
                if (theId != null && theId.getValue() != null) {
                        return !(theId.getValue().startsWith("urn:") || theId.getValue().startsWith("#"));
                }
                return true;
        }

        private boolean shouldSwapBinaryToActualResource(
                        IBaseResource theResource, String theResourceType, IIdType theNextResourceId) {
                if ("Binary".equalsIgnoreCase(theResourceType)
                                && theNextResourceId.getResourceType() != null
                                && !theNextResourceId.getResourceType().equalsIgnoreCase("Binary")) {
                        return true;
                } else {
                        return false;
                }
        }

        private void setConditionalUrlToBeValidatedLater(
                        Map<String, IIdType> theConditionalUrlToIdMap, String theMatchUrl, IIdType theId) {
                if (!isBlank(theMatchUrl)) {
                        theConditionalUrlToIdMap.put(theMatchUrl, theId);
                }
        }

        /**
         * After transaction processing and resolution of indexes and references, we want to validate that the resources that were stored _actually_
         * match the conditional URLs that they were brought in on.
         */
        private void validateAllInsertsMatchTheirConditionalUrls(
                        Map<IIdType, DaoMethodOutcome> theIdToPersistedOutcome,
                        Map<String, IIdType> conditionalUrlToIdMap,
                        RequestDetails theRequest) {
                conditionalUrlToIdMap.entrySet().stream()
                                .filter(entry -> entry.getKey() != null)
                                .forEach(entry -> {
                                        String matchUrl = entry.getKey();
                                        IIdType value = entry.getValue();
                                        DaoMethodOutcome daoMethodOutcome = theIdToPersistedOutcome.get(value);
                                        if (daoMethodOutcome != null
                                                        && !daoMethodOutcome.isNop()
                                                        && daoMethodOutcome.getResource() != null) {
                                                InMemoryMatchResult match =
                                                                mySearchParamMatcher.match(matchUrl, daoMethodOutcome.getResource(), theRequest);
                                                if (ourLog.isDebugEnabled()) {
                                                        ourLog.debug(
                                                                        "Checking conditional URL [{}] against resource with ID [{}]: Supported?:[{}], Matched?:[{}]",
                                                                        matchUrl,
                                                                        value,
                                                                        match.supported(),
                                                                        match.matched());
                                                }
                                                if (match.supported()) {
                                                        if (!match.matched()) {
                                                                String msg = myContext
                                                                                .getLocalizer()
                                                                                .getMessage(
                                                                                                BaseTransactionProcessor.class,
                                                                                                "invalidConditionalUrlResourceDoesntMatch",
                                                                                                matchUrl);
                                                                throw new PreconditionFailedException(Msg.code(539) + msg);
                                                        }
                                                }
                                        }
                                });
        }

        /**
         * Checks for any delete conflicts.
         *
         * @param theDeleteConflicts  - set of delete conflicts
         * @param theDeletedResources - set of deleted resources
         * @param theUpdatedResources - list of updated resources
         */
        private void checkForDeleteConflicts(
                        DeleteConflictList theDeleteConflicts,
                        Set<String> theDeletedResources,
                        List<IBaseResource> theUpdatedResources) {
                for (Iterator<DeleteConflict> iter = theDeleteConflicts.iterator(); iter.hasNext(); ) {
                        DeleteConflict nextDeleteConflict = iter.next();

                        /*
                         * If we have a conflict, it means we can't delete Resource/A because
                         * Resource/B has a reference to it. We'll ignore that conflict though
                         * if it turns out we're also deleting Resource/B in this transaction.
                         */
                        if (theDeletedResources.contains(
                                        nextDeleteConflict.getSourceId().toUnqualifiedVersionless().getValue())) {
                                iter.remove();
                                continue;
                        }

                        /*
                         * And then, this is kind of a last ditch check. It's also ok to delete
                         * Resource/A if Resource/B isn't being deleted, but it is being UPDATED
                         * in this transaction, and the updated version of it has no references
                         * to Resource/A any more.
                         */
                        String sourceId =
                                        nextDeleteConflict.getSourceId().toUnqualifiedVersionless().getValue();
                        String targetId =
                                        nextDeleteConflict.getTargetId().toUnqualifiedVersionless().getValue();
                        Optional<IBaseResource> updatedSource = theUpdatedResources.stream()
                                        .filter(t -> sourceId.equals(
                                                        t.getIdElement().toUnqualifiedVersionless().getValue()))
                                        .findFirst();
                        if (updatedSource.isPresent()) {
                                List<ResourceReferenceInfo> referencesInSource =
                                                myContext.newTerser().getAllResourceReferences(updatedSource.get());
                                boolean sourceStillReferencesTarget = referencesInSource.stream()
                                                .anyMatch(t -> targetId.equals(t.getResourceReference()
                                                                .getReferenceElement()
                                                                .toUnqualifiedVersionless()
                                                                .getValue()));
                                if (!sourceStillReferencesTarget) {
                                        iter.remove();
                                }
                        }
                }
                DeleteConflictUtil.validateDeleteConflictsEmptyOrThrowException(myContext, theDeleteConflicts);
        }

        /**
         * This method replaces any placeholder references in the
         * source transaction Bundle with their actual targets, then stores the resource contents and indexes
         * in the database. This is trickier than you'd think because of a couple of possibilities during the
         * save:
         * * There may be resources that have not changed (e.g. an update/PUT with a resource body identical
         * to what is already in the database)
         * * There may be resources with auto-versioned references, meaning we're replacing certain references
         * in the resource with a versioned references, referencing the current version at the time of the
         * transaction processing
         * * There may by auto-versioned references pointing to these unchanged targets
         * <p>
         * If we're not doing any auto-versioned references, we'll just iterate through all resources in the
         * transaction and save them one at a time.
         * <p>
         * However, if we have any auto-versioned references we do this in 2 passes: First the resources from the
         * transaction that don't have any auto-versioned references are stored. We do them first since there's
         * a chance they may be a NOP and we'll need to account for their version number not actually changing.
         * Then we do a second pass for any resources that have auto-versioned references. These happen in a separate
         * pass because it's too complex to try and insert the auto-versioned references and still
         * account for NOPs, so we block NOPs in that pass.
         */
        private void resolveReferencesThenSaveAndIndexResources(
                        RequestDetails theRequest,
                        TransactionDetails theTransactionDetails,
                        IdSubstitutionMap theIdSubstitutions,
                        Map<IIdType, DaoMethodOutcome> theIdToPersistedOutcome,
                        StopWatch theTransactionStopWatch,
                        EntriesToProcessMap theEntriesToProcess,
                        Set<IIdType> theNonUpdatedEntities,
                        Set<IBasePersistedResource> theUpdatedEntities) {
                FhirTerser terser = myContext.newTerser();
                theTransactionStopWatch.startTask("Index " + theIdToPersistedOutcome.size() + " resources");
                IdentityHashMap<DaoMethodOutcome, Set<IBaseReference>> deferredIndexesForAutoVersioning = null;
                int i = 0;
                for (DaoMethodOutcome nextOutcome : theIdToPersistedOutcome.values()) {

                        if (i++ % 250 == 0) {
                                ourLog.debug(
                                                "Have indexed {} entities out of {} in transaction",
                                                i,
                                                theIdToPersistedOutcome.values().size());
                        }

                        if (nextOutcome.isNop()) {
                                continue;
                        }

                        IBaseResource nextResource = nextOutcome.getResource();
                        if (nextResource == null) {
                                continue;
                        }

                        Set<IBaseReference> referencesToAutoVersion =
                                        BaseStorageDao.extractReferencesToAutoVersion(myContext, myStorageSettings, nextResource);
                        Set<IBaseReference> referencesToKeepClientSuppliedVersion =
                                        BaseStorageDao.extractReferencesToAvoidReplacement(myContext, nextResource);

                        if (referencesToAutoVersion.isEmpty()) {
                                // no references to autoversion - we can do the resolve and save now
                                resolveReferencesThenSaveAndIndexResource(
                                                theRequest,
                                                theTransactionDetails,
                                                theIdSubstitutions,
                                                theIdToPersistedOutcome,
                                                theEntriesToProcess,
                                                theNonUpdatedEntities,
                                                theUpdatedEntities,
                                                terser,
                                                nextOutcome,
                                                nextResource,
                                                referencesToAutoVersion, // this is empty
                                                referencesToKeepClientSuppliedVersion);
                        } else {
                                // we have autoversioned things to defer until later
                                if (deferredIndexesForAutoVersioning == null) {
                                        deferredIndexesForAutoVersioning = new IdentityHashMap<>();
                                }
                                deferredIndexesForAutoVersioning.put(nextOutcome, referencesToAutoVersion);
                        }
                }

                // If we have any resources we'll be auto-versioning, index these next
                if (deferredIndexesForAutoVersioning != null) {
                        for (Map.Entry<DaoMethodOutcome, Set<IBaseReference>> nextEntry :
                                        deferredIndexesForAutoVersioning.entrySet()) {
                                DaoMethodOutcome nextOutcome = nextEntry.getKey();
                                Set<IBaseReference> referencesToAutoVersion = nextEntry.getValue();
                                IBaseResource nextResource = nextOutcome.getResource();
                                Set<IBaseReference> referencesToKeepClientSuppliedVersion =
                                                BaseStorageDao.extractReferencesToAvoidReplacement(myContext, nextResource);

                                resolveReferencesThenSaveAndIndexResource(
                                                theRequest,
                                                theTransactionDetails,
                                                theIdSubstitutions,
                                                theIdToPersistedOutcome,
                                                theEntriesToProcess,
                                                theNonUpdatedEntities,
                                                theUpdatedEntities,
                                                terser,
                                                nextOutcome,
                                                nextResource,
                                                referencesToAutoVersion,
                                                referencesToKeepClientSuppliedVersion);
                        }
                }
        }

        private void resolveReferencesThenSaveAndIndexResource(
                        RequestDetails theRequest,
                        TransactionDetails theTransactionDetails,
                        IdSubstitutionMap theIdSubstitutions,
                        Map<IIdType, DaoMethodOutcome> theIdToPersistedOutcome,
                        EntriesToProcessMap theEntriesToProcess,
                        Set<IIdType> theNonUpdatedEntities,
                        Set<IBasePersistedResource> theUpdatedEntities,
                        FhirTerser theTerser,
                        DaoMethodOutcome theDaoMethodOutcome,
                        IBaseResource theResource,
                        Set<IBaseReference> theReferencesToAutoVersion,
                        Set<IBaseReference> theReferencesToKeepClientSuppliedVersion) {
                // References
                List<ResourceReferenceInfo> allRefs = theTerser.getAllResourceReferences(theResource);
                for (ResourceReferenceInfo nextRef : allRefs) {
                        IBaseReference resourceReference = nextRef.getResourceReference();
                        IIdType nextId = resourceReference.getReferenceElement();
                        IIdType newId = null;
                        if (!nextId.hasIdPart()) {
                                if (resourceReference.getResource() != null) {
                                        IIdType targetId = resourceReference.getResource().getIdElement();
                                        if (targetId.getValue() == null) {
                                                // This means it's a contained resource
                                                continue;
                                        } else if (theIdSubstitutions.containsTarget(targetId)) {
                                                newId = targetId;
                                        } else {
                                                throw new InternalErrorException(Msg.code(540)
                                                                + "References by resource with no reference ID are not supported in DAO layer");
                                        }
                                } else {
                                        continue;
                                }
                        }
                        if (newId != null || theIdSubstitutions.containsSource(nextId)) {
                                if (shouldReplaceResourceReference(
                                                theReferencesToAutoVersion, theReferencesToKeepClientSuppliedVersion, resourceReference)) {
                                        if (newId == null) {
                                                newId = theIdSubstitutions.getForSource(nextId);
                                        }
                                        if (newId != null) {
                                                ourLog.debug(" * Replacing resource ref {} with {}", nextId, newId);
                                                if (theReferencesToAutoVersion.contains(resourceReference)) {
                                                        replaceResourceReference(newId, resourceReference, theTransactionDetails);
                                                } else {
                                                        replaceResourceReference(newId.toVersionless(), resourceReference, theTransactionDetails);
                                                }
                                        }
                                }
                        } else if (nextId.getValue().startsWith("urn:")) {
                                throw new InvalidRequestException(
                                                Msg.code(541) + "Unable to satisfy placeholder ID " + nextId.getValue()
                                                                + " found in element named '" + nextRef.getName() + "' within resource of type: "
                                                                + theResource.getIdElement().getResourceType());
                        } else {
                                // get a map of
                                // existing ids -> PID (for resources that exist in the DB)
                                // should this be allPartitions?
                                ResourcePersistentIdMap resourceVersionMap = myResourceVersionSvc.getLatestVersionIdsForResourceIds(
                                                RequestPartitionId.allPartitions(),
                                                theReferencesToAutoVersion.stream()
                                                                .map(IBaseReference::getReferenceElement)
                                                                .collect(Collectors.toList()));

                                for (IBaseReference baseRef : theReferencesToAutoVersion) {
                                        IIdType id = baseRef.getReferenceElement();
                                        if (!resourceVersionMap.containsKey(id)
                                                        && myStorageSettings.isAutoCreatePlaceholderReferenceTargets()) {
                                                // not in the db, but autocreateplaceholders is true
                                                // so the version we'll set is "1" (since it will be
                                                // created later)
                                                String newRef = id.withVersion("1").getValue();
                                                id.setValue(newRef);
                                        } else {
                                                // we will add the looked up info to the transaction
                                                // for later
                                                if (resourceVersionMap.containsKey(id)) {
                                                        theTransactionDetails.addResolvedResourceId(
                                                                        id, resourceVersionMap.getResourcePersistentId(id));
                                                }
                                        }
                                }

                                if (theReferencesToAutoVersion.contains(resourceReference)) {
                                        DaoMethodOutcome outcome = theIdToPersistedOutcome.get(nextId);

                                        if (outcome != null && !outcome.isNop() && !Boolean.TRUE.equals(outcome.getCreated())) {
                                                replaceResourceReference(nextId, resourceReference, theTransactionDetails);
                                        }

                                        // if referenced resource is not in transaction but exists in the DB, resolving its version
                                        IResourcePersistentId persistedReferenceId = resourceVersionMap.getResourcePersistentId(nextId);
                                        if (outcome == null && persistedReferenceId != null && persistedReferenceId.getVersion() != null) {
                                                IIdType newReferenceId = nextId.withVersion(
                                                                persistedReferenceId.getVersion().toString());
                                                replaceResourceReference(newReferenceId, resourceReference, theTransactionDetails);
                                        }
                                }
                        }
                }

                // URIs
                Class<? extends IPrimitiveType<?>> uriType = (Class<? extends IPrimitiveType<?>>)
                                myContext.getElementDefinition("uri").getImplementingClass();
                List<? extends IPrimitiveType<?>> allUris = theTerser.getAllPopulatedChildElementsOfType(theResource, uriType);
                for (IPrimitiveType<?> nextRef : allUris) {
                        if (nextRef instanceof IIdType) {
                                continue; // No substitution on the resource ID itself!
                        }
                        String nextUriString = nextRef.getValueAsString();
                        if (isNotBlank(nextUriString)) {
                                if (theIdSubstitutions.containsSource(nextUriString)) {
                                        IIdType newId = theIdSubstitutions.getForSource(nextUriString);
                                        ourLog.debug(" * Replacing resource ref {} with {}", nextUriString, newId);

                                        String existingValue = nextRef.getValueAsString();
                                        theTransactionDetails.addRollbackUndoAction(() -> nextRef.setValueAsString(existingValue));

                                        nextRef.setValueAsString(newId.toVersionless().getValue());
                                } else {
                                        ourLog.debug(" * Reference [{}] does not exist in bundle", nextUriString);
                                }
                        }
                }

                IPrimitiveType<Date> deletedInstantOrNull = ResourceMetadataKeyEnum.DELETED_AT.get(theResource);
                Date deletedTimestampOrNull = deletedInstantOrNull != null ? deletedInstantOrNull.getValue() : null;

                IFhirResourceDao<? extends IBaseResource> dao = myDaoRegistry.getResourceDao(theResource.getClass());
                IJpaDao jpaDao = (IJpaDao) dao;

                IBasePersistedResource updateOutcome = null;
                if (theUpdatedEntities.contains(theDaoMethodOutcome.getEntity())) {
                        boolean forceUpdateVersion = !theReferencesToAutoVersion.isEmpty();
                        String matchUrl = theDaoMethodOutcome.getMatchUrl();
                        RestOperationTypeEnum operationType = theDaoMethodOutcome.getOperationType();
                        DaoMethodOutcome daoMethodOutcome = jpaDao.updateInternal(
                                        theRequest,
                                        theResource,
                                        matchUrl,
                                        true,
                                        forceUpdateVersion,
                                        theDaoMethodOutcome.getEntity(),
                                        theResource.getIdElement(),
                                        theDaoMethodOutcome.getPreviousResource(),
                                        operationType,
                                        theTransactionDetails);
                        updateOutcome = daoMethodOutcome.getEntity();
                        theDaoMethodOutcome = daoMethodOutcome;
                } else if (!theNonUpdatedEntities.contains(theDaoMethodOutcome.getId())) {
                        updateOutcome = jpaDao.updateEntity(
                                        theRequest,
                                        theResource,
                                        theDaoMethodOutcome.getEntity(),
                                        deletedTimestampOrNull,
                                        true,
                                        false,
                                        theTransactionDetails,
                                        false,
                                        true);
                }

                // Make sure we reflect the actual final version for the resource.
                if (updateOutcome != null) {
                        IIdType newId = updateOutcome.getIdDt();

                        IIdType entryId = theEntriesToProcess.getIdWithVersionlessComparison(newId);
                        if (entryId != null && !StringUtils.equals(entryId.getValue(), newId.getValue())) {
                                entryId.setValue(newId.getValue());
                        }

                        theDaoMethodOutcome.setId(newId);

                        theIdSubstitutions.updateTargets(newId);

                        // This will only be null if we're not intending to return an OO
                        IBaseOperationOutcome operationOutcome = theDaoMethodOutcome.getOperationOutcome();
                        if (operationOutcome != null) {

                                List<IIdType> autoCreatedPlaceholders =
                                                theTransactionDetails.getAutoCreatedPlaceholderResourcesAndClear();
                                for (IIdType autoCreatedPlaceholder : autoCreatedPlaceholders) {
                                        BaseStorageDao.addIssueToOperationOutcomeForAutoCreatedPlaceholder(
                                                        myContext, autoCreatedPlaceholder, operationOutcome);
                                }

                                IBase responseEntry = theEntriesToProcess.getResponseBundleEntryWithVersionlessComparison(newId);
                                myVersionAdapter.setResponseOutcome(responseEntry, operationOutcome);
                        }
                }
        }

        /**
         * We should replace the references when
         * 1. It is not a reference we should keep the client-supplied version for as configured by `DontStripVersionsFromReferences` or
         * 2. It is a reference that has been identified for auto versioning or
         * 3. Is a placeholder reference
         *
         * @param theReferencesToAutoVersion               list of references identified for auto versioning
         * @param theReferencesToKeepClientSuppliedVersion list of references that we should not strip the version for
         * @param theResourceReference                     the resource reference
         * @return true if we should replace the resource reference, false if we should keep the client provided reference
         */
        private boolean shouldReplaceResourceReference(
                        Set<IBaseReference> theReferencesToAutoVersion,
                        Set<IBaseReference> theReferencesToKeepClientSuppliedVersion,
                        IBaseReference theResourceReference) {
                return (!theReferencesToKeepClientSuppliedVersion.contains(theResourceReference)
                                                && myContext.getParserOptions().isStripVersionsFromReferences())
                                || theReferencesToAutoVersion.contains(theResourceReference)
                                || isPlaceholder(theResourceReference.getReferenceElement());
        }

        private void replaceResourceReference(
                        IIdType theReferenceId, IBaseReference theResourceReference, TransactionDetails theTransactionDetails) {
                addRollbackReferenceRestore(theTransactionDetails, theResourceReference);
                theResourceReference.setReference(theReferenceId.getValue());
                theResourceReference.setResource(null);
        }

        private void addRollbackReferenceRestore(
                        TransactionDetails theTransactionDetails, IBaseReference resourceReference) {
                String existingValue = resourceReference.getReferenceElement().getValue();
                theTransactionDetails.addRollbackUndoAction(() -> resourceReference.setReference(existingValue));
        }

        private void validateNoDuplicates(
                        RequestDetails theRequest,
                        TransactionDetails theTransactionDetails,
                        String theActionName,
                        Map<String, Class<? extends IBaseResource>> conditionalRequestUrls,
                        Collection<DaoMethodOutcome> thePersistedOutcomes) {

                Map<ResourceTable, ResourceIndexedSearchParams> existingSearchParams =
                                theTransactionDetails.getOrCreateUserData(
                                                HapiTransactionService.XACT_USERDATA_KEY_EXISTING_SEARCH_PARAMS, Collections::emptyMap);

                IdentityHashMap<IBaseResource, ResourceIndexedSearchParams> resourceToIndexedParams =
                                new IdentityHashMap<>(thePersistedOutcomes.size());
                thePersistedOutcomes.stream()
                                .filter(t -> !t.isNop())
                                // N.B. GGG: This validation never occurs for mongo, as nothing is a ResourceTable.
                                .filter(t -> t.getEntity() instanceof ResourceTable)
                                .filter(t -> t.getEntity().getDeleted() == null)
                                .filter(t -> t.getResource() != null)
                                .forEach(t -> {
                                        ResourceTable entity = (ResourceTable) t.getEntity();
                                        ResourceIndexedSearchParams params = existingSearchParams.get(entity);
                                        if (params == null) {
                                                params = ResourceIndexedSearchParams.withLists(entity);
                                        }
                                        resourceToIndexedParams.put(t.getResource(), params);
                                });

                for (Map.Entry<String, Class<? extends IBaseResource>> nextEntry : conditionalRequestUrls.entrySet()) {
                        String matchUrl = nextEntry.getKey();
                        if (isNotBlank(matchUrl)) {
                                if (matchUrl.startsWith("?")
                                                || (!matchUrl.contains("?")
                                                                && UNQUALIFIED_MATCH_URL_START.matcher(matchUrl).find())) {
                                        StringBuilder b = new StringBuilder();
                                        b.append(myContext.getResourceType(nextEntry.getValue()));
                                        if (!matchUrl.startsWith("?")) {
                                                b.append("?");
                                        }
                                        b.append(matchUrl);
                                        matchUrl = b.toString();
                                }

                                if (!myInMemoryResourceMatcher.canBeEvaluatedInMemory(matchUrl).supported()) {
                                        continue;
                                }

                                int counter = 0;
                                for (Map.Entry<IBaseResource, ResourceIndexedSearchParams> entries :
                                                resourceToIndexedParams.entrySet()) {
                                        ResourceIndexedSearchParams indexedParams = entries.getValue();
                                        IBaseResource resource = entries.getKey();

                                        String resourceType = myContext.getResourceType(resource);
                                        if (!matchUrl.startsWith(resourceType + "?")) {
                                                continue;
                                        }

                                        if (myInMemoryResourceMatcher
                                                        .match(matchUrl, resource, indexedParams, theRequest)
                                                        .matched()) {
                                                counter++;
                                                if (counter > 1) {
                                                        throw new InvalidRequestException(Msg.code(542) + "Unable to process " + theActionName
                                                                        + " - Request would cause multiple resources to match URL: \"" + matchUrl
                                                                        + "\". Does transaction request contain duplicates?");
                                                }
                                        }
                                }
                        }
                }
        }

        protected abstract void flushSession(Map<IIdType, DaoMethodOutcome> theIdToPersistedOutcome);

        private void validateResourcePresent(IBaseResource theResource, Integer theOrder, String theVerb) {
                if (theResource == null) {
                        String msg = myContext
                                        .getLocalizer()
                                        .getMessage(BaseTransactionProcessor.class, "missingMandatoryResource", theVerb, theOrder);
                        throw new InvalidRequestException(Msg.code(543) + msg);
                }
        }

        private IIdType newIdType(String theResourceType, String theResourceId, String theVersion) {
                IdType id = new IdType(theResourceType, theResourceId, theVersion);
                return myContext.getVersion().newIdType().setValue(id.getValue());
        }

        private IIdType newIdType(String theToResourceName, String theIdPart) {
                return newIdType(theToResourceName, theIdPart, null);
        }

        @VisibleForTesting
        public void setDaoRegistry(DaoRegistry theDaoRegistry) {
                myDaoRegistry = theDaoRegistry;
        }

        private IFhirResourceDao getDaoOrThrowException(Class<? extends IBaseResource> theClass) {
                IFhirResourceDao<? extends IBaseResource> dao = myDaoRegistry.getResourceDaoOrNull(theClass);
                if (dao == null) {
                        Set<String> types = new TreeSet<>(myDaoRegistry.getRegisteredDaoTypes());
                        String type = myContext.getResourceType(theClass);
                        String msg = myContext
                                        .getLocalizer()
                                        .getMessage(BaseTransactionProcessor.class, "unsupportedResourceType", type, types.toString());
                        throw new InvalidRequestException(Msg.code(544) + msg);
                }
                return dao;
        }

        private String toResourceName(Class<? extends IBaseResource> theResourceType) {
                return myContext.getResourceType(theResourceType);
        }

        public void setContext(FhirContext theContext) {
                myContext = theContext;
        }

        /**
         * Extracts the transaction url from the entry and verifies it's:
         * <li>not null or blank (unless it is a POST), and</li>
         * <li>is a relative url matching the resourceType it is about</li>
         * <p>
         * For POST requests, the url is allowed to be blank to preserve the existing behavior.
         * <p>
         * Returns the transaction url (or throws an InvalidRequestException if url is missing or not valid)
         */
        private String extractAndVerifyTransactionUrlForEntry(IBase theEntry, String theVerb) {
                String url = extractTransactionUrlOrThrowException(theEntry, theVerb);
                if (url.isEmpty() || isValidResourceTypeUrl(url)) {
                        // for POST requests, the url is allowed to be blank, which is checked in
                        // extractTransactionUrlOrThrowException and an empty string is returned in that case.
                        // That is why empty url is allowed here.
                        return url;
                }

                ourLog.debug("Invalid url. Should begin with a resource type: {}", url);
                String msg = myContext.getLocalizer().getMessage(BaseStorageDao.class, "transactionInvalidUrl", theVerb, url);
                throw new InvalidRequestException(Msg.code(2006) + msg);
        }

        /**
         * Returns true if the provided url is a valid entry request.url.
         * <p>
         * This means:
         * a) not an absolute url (does not start with http/https)
         * b) starts with either a ResourceType or /ResourceType
         */
        private boolean isValidResourceTypeUrl(@Nonnull String theUrl) {
                if (UrlUtil.isAbsolute(theUrl)) {
                        return false;
                } else {
                        int queryStringIndex = theUrl.indexOf("?");
                        String url;
                        if (queryStringIndex > 0) {
                                url = theUrl.substring(0, theUrl.indexOf("?"));
                        } else {
                                url = theUrl;
                        }
                        String[] parts;
                        if (url.startsWith("/")) {
                                parts = url.substring(1).split("/");
                        } else {
                                parts = url.split("/");
                        }
                        Set<String> allResourceTypes = myContext.getResourceTypes();

                        return allResourceTypes.contains(parts[0]);
                }
        }

        /**
         * Extracts the transaction url from the entry and verifies that it is not null/blank, unless it is a POST,
         * and returns it. For POST requests allows null or blank values to keep the existing behaviour and returns
         * an empty string in that case.
         */
        private String extractTransactionUrlOrThrowException(IBase nextEntry, String verb) {
                String url = myVersionAdapter.getEntryRequestUrl(nextEntry);
                if ("POST".equals(verb) && isBlank(url)) {
                        // allow blanks for POST to keep the existing behaviour
                        // returning empty string instead of null to not get NPE later
                        return "";
                }

                if (isBlank(url)) {
                        throw new InvalidRequestException(Msg.code(545)
                                        + myContext.getLocalizer().getMessage(BaseStorageDao.class, "transactionMissingUrl", verb));
                }
                return url;
        }

        private IFhirResourceDao<? extends IBaseResource> toDao(UrlUtil.UrlParts theParts, String theVerb, String theUrl) {
                RuntimeResourceDefinition resType;
                try {
                        resType = myContext.getResourceDefinition(theParts.getResourceType());
                } catch (DataFormatException e) {
                        String msg =
                                        myContext.getLocalizer().getMessage(BaseStorageDao.class, "transactionInvalidUrl", theVerb, theUrl);
                        throw new InvalidRequestException(Msg.code(546) + msg);
                }
                IFhirResourceDao<? extends IBaseResource> dao = null;
                if (resType != null) {
                        dao = myDaoRegistry.getResourceDao(resType.getImplementingClass());
                }
                if (dao == null) {
                        String msg =
                                        myContext.getLocalizer().getMessage(BaseStorageDao.class, "transactionInvalidUrl", theVerb, theUrl);
                        throw new InvalidRequestException(Msg.code(547) + msg);
                }

                return dao;
        }

        private String toMatchUrl(IBase theEntry) {
                String verb = myVersionAdapter.getEntryRequestVerb(myContext, theEntry);
                switch (defaultString(verb)) {
                        case POST:
                                return myVersionAdapter.getEntryIfNoneExist(theEntry);
                        case PUT:
                        case DELETE:
                        case PATCH:
                                String url = extractTransactionUrlOrThrowException(theEntry, verb);
                                UrlUtil.UrlParts parts = UrlUtil.parseUrl(url);
                                if (isBlank(parts.getResourceId())) {
                                        return parts.getResourceType() + '?' + parts.getParams();
                                }
                                return null;
                        default:
                                return null;
                }
        }

        @VisibleForTesting
        public void setInterceptorBroadcasterForUnitTest(IInterceptorBroadcaster theInterceptorBroadcaster) {
                myInterceptorBroadcaster = theInterceptorBroadcaster;
        }

        @VisibleForTesting
        public void setPartitionSettingsForUnitTest(PartitionSettings thePartitionSettings) {
                myPartitionSettings = thePartitionSettings;
        }

        /**
         * Transaction Order, per the spec:
         * <p>
         * Process any DELETE interactions
         * Process any POST interactions
         * Process any PUT interactions
         * Process any PATCH interactions
         * Process any GET interactions
         */
        // @formatter:off
        public class TransactionSorter implements Comparator<IBase> {

                private final Set<String> myPlaceholderIds;

                public TransactionSorter(Set<String> thePlaceholderIds) {
                        myPlaceholderIds = thePlaceholderIds;
                }

                @Override
                public int compare(IBase theO1, IBase theO2) {
                        int o1 = toOrder(theO1);
                        int o2 = toOrder(theO2);

                        if (o1 == o2) {
                                String matchUrl1 = toMatchUrl(theO1);
                                String matchUrl2 = toMatchUrl(theO2);
                                if (isBlank(matchUrl1) && isBlank(matchUrl2)) {
                                        return 0;
                                }
                                if (isBlank(matchUrl1)) {
                                        return -1;
                                }
                                if (isBlank(matchUrl2)) {
                                        return 1;
                                }

                                boolean match1containsSubstitutions = false;
                                boolean match2containsSubstitutions = false;
                                for (String nextPlaceholder : myPlaceholderIds) {
                                        if (matchUrl1.contains(nextPlaceholder)) {
                                                match1containsSubstitutions = true;
                                        }
                                        if (matchUrl2.contains(nextPlaceholder)) {
                                                match2containsSubstitutions = true;
                                        }
                                }

                                if (match1containsSubstitutions && match2containsSubstitutions) {
                                        return 0;
                                }
                                if (!match1containsSubstitutions && !match2containsSubstitutions) {
                                        return 0;
                                }
                                if (match1containsSubstitutions) {
                                        return 1;
                                } else {
                                        return -1;
                                }
                        }

                        return o1 - o2;
                }

                private int toOrder(IBase theO1) {
                        int o1 = 0;
                        if (myVersionAdapter.getEntryRequestVerb(myContext, theO1) != null) {
                                switch (myVersionAdapter.getEntryRequestVerb(myContext, theO1)) {
                                        case "DELETE":
                                                o1 = 1;
                                                break;
                                        case "POST":
                                                o1 = 2;
                                                break;
                                        case "PUT":
                                                o1 = 3;
                                                break;
                                        case "PATCH":
                                                o1 = 4;
                                                break;
                                        case "GET":
                                                o1 = 5;
                                                break;
                                        default:
                                                o1 = 0;
                                                break;
                                }
                        }
                        return o1;
                }
        }

        public class RetriableBundleTask implements Runnable {

                private final CountDownLatch myCompletedLatch;
                private final RequestDetails myRequestDetails;
                private final IBase myNextReqEntry;
                private final Map<Integer, Object> myResponseMap;
                private final int myResponseOrder;
                private final boolean myNestedMode;
                private BaseServerResponseException myLastSeenException;

                protected RetriableBundleTask(
                                CountDownLatch theCompletedLatch,
                                RequestDetails theRequestDetails,
                                Map<Integer, Object> theResponseMap,
                                int theResponseOrder,
                                IBase theNextReqEntry,
                                boolean theNestedMode) {
                        this.myCompletedLatch = theCompletedLatch;
                        this.myRequestDetails = theRequestDetails;
                        this.myNextReqEntry = theNextReqEntry;
                        this.myResponseMap = theResponseMap;
                        this.myResponseOrder = theResponseOrder;
                        this.myNestedMode = theNestedMode;
                        this.myLastSeenException = null;
                }

                private void processBatchEntry() {
                        IBaseBundle subRequestBundle =
                                        myVersionAdapter.createBundle(org.hl7.fhir.r4.model.Bundle.BundleType.TRANSACTION.toCode());
                        myVersionAdapter.addEntry(subRequestBundle, myNextReqEntry);

                        IInterceptorBroadcaster compositeBroadcaster =
                                        CompositeInterceptorBroadcaster.newCompositeBroadcaster(myInterceptorBroadcaster, myRequestDetails);

                        // Interceptor call: STORAGE_TRANSACTION_PROCESSING
                        if (compositeBroadcaster.hasHooks(Pointcut.STORAGE_TRANSACTION_PROCESSING)) {
                                HookParams params = new HookParams()
                                                .add(RequestDetails.class, myRequestDetails)
                                                .addIfMatchesType(ServletRequestDetails.class, myRequestDetails)
                                                .add(IBaseBundle.class, subRequestBundle);
                                compositeBroadcaster.callHooks(Pointcut.STORAGE_TRANSACTION_PROCESSING, params);
                        }

                        IBaseBundle nextResponseBundle = processTransactionAsSubRequest(
                                        myRequestDetails, subRequestBundle, "Batch sub-request", myNestedMode);

                        IBase subResponseEntry =
                                        (IBase) myVersionAdapter.getEntries(nextResponseBundle).get(0);
                        myResponseMap.put(myResponseOrder, subResponseEntry);

                        /*
                         * If the individual entry didn't have a resource in its response, bring the sub-transaction's OperationOutcome across so the client can see it
                         */
                        if (myVersionAdapter.getResource(subResponseEntry) == null) {
                                IBase nextResponseBundleFirstEntry =
                                                (IBase) myVersionAdapter.getEntries(nextResponseBundle).get(0);
                                myResponseMap.put(myResponseOrder, nextResponseBundleFirstEntry);
                        }
                }

                private boolean processBatchEntryWithRetry() {
                        int maxAttempts = 3;
                        for (int attempt = 1; ; attempt++) {
                                try {
                                        processBatchEntry();
                                        return true;
                                } catch (BaseServerResponseException e) {
                                        // If we catch a known and structured exception from HAPI, just fail.
                                        myLastSeenException = e;
                                        return false;
                                } catch (Throwable t) {
                                        myLastSeenException = new InternalErrorException(t);
                                        // If we have caught a non-tag-storage failure we are unfamiliar with, or we have exceeded max
                                        // attempts, exit.
                                        if (!DaoFailureUtil.isTagStorageFailure(t) || attempt >= maxAttempts) {
                                                ourLog.error("Failure during BATCH sub transaction processing", t);
                                                return false;
                                        }
                                }
                        }
                }

                @Override
                public void run() {
                        boolean success = processBatchEntryWithRetry();
                        if (!success) {
                                populateResponseMapWithLastSeenException();
                        }

                        // checking for the parallelism
                        ourLog.debug("processing batch for {} is completed", myVersionAdapter.getEntryRequestUrl(myNextReqEntry));
                        myCompletedLatch.countDown();
                }

                private void populateResponseMapWithLastSeenException() {
                        ServerResponseExceptionHolder caughtEx = new ServerResponseExceptionHolder();
                        caughtEx.setException(myLastSeenException);
                        myResponseMap.put(myResponseOrder, caughtEx);
                }
        }

        private static class ServerResponseExceptionHolder {
                private BaseServerResponseException myException;

                public BaseServerResponseException getException() {
                        return myException;
                }

                public void setException(BaseServerResponseException myException) {
                        this.myException = myException;
                }
        }

        public static boolean isPlaceholder(IIdType theId) {
                if (theId != null && theId.getValue() != null) {
                        return theId.getValue().startsWith("urn:oid:") || theId.getValue().startsWith("urn:uuid:");
                }
                return false;
        }

        public static String toStatusString(int theStatusCode) {
                return theStatusCode + " " + defaultString(Constants.HTTP_STATUS_NAMES.get(theStatusCode));
        }

        /**
         * Given a match URL containing
         *
         * @param theIdSubstitutions
         * @param theMatchUrl
         * @return
         */
        public static String performIdSubstitutionsInMatchUrl(IdSubstitutionMap theIdSubstitutions, String theMatchUrl) {
                String matchUrl = theMatchUrl;
                if (isNotBlank(matchUrl) && !theIdSubstitutions.isEmpty()) {
                        int startIdx = 0;
                        while (startIdx != -1) {

                                int endIdx = matchUrl.indexOf('&', startIdx + 1);
                                if (endIdx == -1) {
                                        endIdx = matchUrl.length();
                                }

                                int equalsIdx = matchUrl.indexOf('=', startIdx + 1);

                                int searchFrom;
                                if (equalsIdx == -1) {
                                        searchFrom = matchUrl.length();
                                } else if (equalsIdx >= endIdx) {
                                        // First equals we found is from a subsequent parameter
                                        searchFrom = matchUrl.length();
                                } else {
                                        String paramValue = matchUrl.substring(equalsIdx + 1, endIdx);
                                        boolean isUrn = isUrn(paramValue);
                                        boolean isUrnEscaped = !isUrn && isUrnEscaped(paramValue);
                                        if (isUrn || isUrnEscaped) {
                                                if (isUrnEscaped) {
                                                        paramValue = UrlUtil.unescape(paramValue);
                                                }
                                                IIdType replacement = theIdSubstitutions.getForSource(paramValue);
                                                if (replacement != null) {
                                                        String replacementValue;
                                                        if (replacement.hasVersionIdPart()) {
                                                                replacementValue = replacement.toVersionless().getValue();
                                                        } else {
                                                                replacementValue = replacement.getValue();
                                                        }
                                                        matchUrl = matchUrl.substring(0, equalsIdx + 1)
                                                                        + replacementValue
                                                                        + matchUrl.substring(endIdx);
                                                        searchFrom = equalsIdx + 1 + replacementValue.length();
                                                } else {
                                                        searchFrom = endIdx;
                                                }
                                        } else {
                                                searchFrom = endIdx;
                                        }
                                }

                                if (searchFrom >= matchUrl.length()) {
                                        break;
                                }

                                startIdx = matchUrl.indexOf('&', searchFrom);
                        }
                }
                return matchUrl;
        }

        private static boolean isUrn(@Nonnull String theId) {
                return theId.startsWith(URN_PREFIX);
        }

        private static boolean isUrnEscaped(@Nonnull String theId) {
                return theId.startsWith(URN_PREFIX_ESCAPED);
        }
}