001package ca.uhn.fhir.rest.server;
002
003/*
004 * #%L
005 * HAPI FHIR - Server Framework
006 * %%
007 * Copyright (C) 2014 - 2022 Smile CDR, Inc.
008 * %%
009 * Licensed under the Apache License, Version 2.0 (the "License");
010 * you may not use this file except in compliance with the License.
011 * You may obtain a copy of the License at
012 *
013 * http://www.apache.org/licenses/LICENSE-2.0
014 *
015 * Unless required by applicable law or agreed to in writing, software
016 * distributed under the License is distributed on an "AS IS" BASIS,
017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
018 * See the License for the specific language governing permissions and
019 * limitations under the License.
020 * #L%
021 */
022
023import ca.uhn.fhir.rest.api.server.IBundleProvider;
024import ca.uhn.fhir.rest.api.server.RequestDetails;
025import org.apache.commons.lang3.Validate;
026
027import java.util.LinkedHashMap;
028import java.util.UUID;
029
030public class FifoMemoryPagingProvider extends BasePagingProvider {
031
032        private final LinkedHashMap<String, IBundleProvider> myBundleProviders;
033        private final int mySize;
034
035        public FifoMemoryPagingProvider(int theSize) {
036                Validate.isTrue(theSize > 0, "theSize must be greater than 0");
037
038                mySize = theSize;
039                myBundleProviders = new LinkedHashMap<>(mySize);
040        }
041
042        @Override
043        public synchronized IBundleProvider retrieveResultList(RequestDetails theRequest, String theId) {
044                return myBundleProviders.get(theId);
045        }
046
047        @Override
048        public synchronized String storeResultList(RequestDetails theRequestDetails, IBundleProvider theList) {
049                while (myBundleProviders.size() > mySize) {
050                        myBundleProviders.remove(myBundleProviders.keySet().iterator().next());
051                }
052
053                String key = UUID.randomUUID().toString();
054                myBundleProviders.put(key, theList);
055                return key;
056        }
057
058}