001/*-
002 * #%L
003 * HAPI FHIR JPA Server
004 * %%
005 * Copyright (C) 2014 - 2024 Smile CDR, Inc.
006 * %%
007 * Licensed under the Apache License, Version 2.0 (the "License");
008 * you may not use this file except in compliance with the License.
009 * You may obtain a copy of the License at
010 *
011 *      http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 * #L%
019 */
020package ca.uhn.fhir.jpa.search.builder;
021
022import ca.uhn.fhir.jpa.model.dao.JpaPid;
023import ca.uhn.fhir.jpa.search.builder.models.ResolvedSearchQueryExecutor;
024import jakarta.annotation.Nonnull;
025import org.apache.commons.lang3.Validate;
026
027import java.util.Iterator;
028import java.util.List;
029
030public class SearchQueryExecutors {
031
032        public static ISearchQueryExecutor limited(ISearchQueryExecutor theExecutor, long theLimit) {
033                Validate.isTrue(theLimit >= 0, "limit must be non-negative");
034
035                return new ISearchQueryExecutor() {
036                        long myCount = 0;
037
038                        @Override
039                        public void close() {
040                                theExecutor.close();
041                        }
042
043                        @Override
044                        public boolean hasNext() {
045                                return theExecutor.hasNext() && myCount < theLimit;
046                        }
047
048                        @Override
049                        public Long next() {
050                                myCount += 1;
051                                return theExecutor.next();
052                        }
053                };
054        }
055
056        @Nonnull
057        public static ISearchQueryExecutor from(List<Long> rawPids) {
058                return new ResolvedSearchQueryExecutor(rawPids);
059        }
060
061        public static ISearchQueryExecutor from(Iterator<JpaPid> theIterator) {
062                return new JpaPidQueryAdaptor(theIterator);
063        }
064
065        public static ISearchQueryExecutor from(Iterable<JpaPid> theIterable) {
066                return new JpaPidQueryAdaptor(theIterable.iterator());
067        }
068
069        static class JpaPidQueryAdaptor implements ISearchQueryExecutor {
070                final Iterator<JpaPid> myIterator;
071
072                JpaPidQueryAdaptor(Iterator<JpaPid> theIterator) {
073                        myIterator = theIterator;
074                }
075
076                @Override
077                public void close() {}
078
079                @Override
080                public boolean hasNext() {
081                        return myIterator.hasNext();
082                }
083
084                @Override
085                public Long next() {
086                        JpaPid next = myIterator.next();
087                        return next == null ? null : next.getId();
088                }
089        }
090}