001package ca.uhn.fhir.rest.server;
002
003/*
004 * #%L
005 * HAPI FHIR - Core Library
006 * %%
007 * Copyright (C) 2014 - 2017 University Health Network
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 java.util.LinkedHashMap;
024import java.util.UUID;
025
026import org.apache.commons.lang3.Validate;
027
028public class FifoMemoryPagingProvider extends BasePagingProvider implements IPagingProvider {
029
030        private LinkedHashMap<String, IBundleProvider> myBundleProviders;
031        private int mySize;
032
033        public FifoMemoryPagingProvider(int theSize) {
034                Validate.isTrue(theSize > 0, "theSize must be greater than 0");
035
036                mySize = theSize;
037                myBundleProviders = new LinkedHashMap<String, IBundleProvider>(mySize);
038        }
039
040        @Override
041        public synchronized IBundleProvider retrieveResultList(String theId) {
042                return myBundleProviders.get(theId);
043        }
044
045        @Override
046        public synchronized String storeResultList(IBundleProvider theList) {
047                while (myBundleProviders.size() > mySize) {
048                        myBundleProviders.remove(myBundleProviders.keySet().iterator().next());
049                }
050
051                String key = UUID.randomUUID().toString();
052                myBundleProviders.put(key, theList);
053                return key;
054        }
055
056}