001/*-
002 * #%L
003 * HAPI FHIR JPA - Search Parameters
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.cache;
021
022import ca.uhn.fhir.jpa.searchparam.SearchParameterMap;
023
024import java.time.Instant;
025
026/**
027 * This is a handle to the cache created by {@link IResourceChangeListenerRegistry} when a listener is registered.
028 * This this handle can be used to refresh the cache if required.
029 */
030public interface IResourceChangeListenerCache {
031        /**
032         * @return the search parameter map the listener was registered with
033         */
034        SearchParameterMap getSearchParameterMap();
035
036        /**
037         * @return whether the cache has been initialized.  (If not, the cache will be empty.)
038         */
039        boolean isInitialized();
040
041        /**
042         * @return the name of the resource type the listener was registered with
043         */
044        String getResourceName();
045
046        /**
047         * @return the next scheduled time the cache will search the repository, update its cache and notify
048         * its listener of any changes
049         */
050        Instant getNextRefreshTime();
051
052        /**
053         * sets the nextRefreshTime to {@link Instant.MIN} so that the cache will be refreshed and listeners notified in another thread
054         * the next time cache refresh times are checked (every {@link ResourceChangeListenerCacheRefresherImpl.LOCAL_REFRESH_INTERVAL_MS}.
055         */
056        void requestRefresh();
057
058        /**
059         * Refresh the cache immediately in the current thread and notify its listener if there are any changes
060         * @return counts of detected resource creates, updates and deletes
061         */
062        ResourceChangeResult forceRefresh();
063
064        /**
065         * If nextRefreshTime is in the past, then update the cache with the current repository contents and notify its listener of any changes
066         * @return counts of detected resource creates, updates and deletes
067         */
068        ResourceChangeResult refreshCacheIfNecessary();
069
070        // TODO KHS in the future support adding new listeners to existing caches
071}