001/*
002 * #%L
003 * HAPI FHIR - Server Framework
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.rest.server;
021
022import ca.uhn.fhir.rest.api.server.IBundleProvider;
023import ca.uhn.fhir.rest.api.server.RequestDetails;
024import org.apache.commons.lang3.Validate;
025
026import java.util.LinkedHashMap;
027import java.util.UUID;
028
029public class FifoMemoryPagingProvider extends BasePagingProvider {
030
031        private final LinkedHashMap<String, IBundleProvider> myBundleProviders;
032        private final int mySize;
033
034        public FifoMemoryPagingProvider(int theSize) {
035                Validate.isTrue(theSize > 0, "theSize must be greater than 0");
036
037                mySize = theSize;
038                myBundleProviders = new LinkedHashMap<>(mySize);
039        }
040
041        @Override
042        public synchronized IBundleProvider retrieveResultList(RequestDetails theRequest, String theId) {
043                return myBundleProviders.get(theId);
044        }
045
046        @Override
047        public synchronized String storeResultList(RequestDetails theRequestDetails, IBundleProvider theList) {
048                while (myBundleProviders.size() > mySize) {
049                        myBundleProviders.remove(myBundleProviders.keySet().iterator().next());
050                }
051
052                String key = UUID.randomUUID().toString();
053                myBundleProviders.put(key, theList);
054                return key;
055        }
056}