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.util;
021
022import ca.uhn.fhir.i18n.Msg;
023import ca.uhn.fhir.jpa.model.sched.HapiJob;
024import ca.uhn.fhir.jpa.model.sched.IHasScheduledJobs;
025import ca.uhn.fhir.jpa.model.sched.ISchedulerService;
026import ca.uhn.fhir.jpa.model.sched.ScheduledJobDefinition;
027import ca.uhn.fhir.rest.server.exceptions.InternalErrorException;
028import com.google.common.annotations.VisibleForTesting;
029import org.apache.commons.lang3.time.DateUtils;
030import org.quartz.JobExecutionContext;
031import org.slf4j.Logger;
032import org.slf4j.LoggerFactory;
033import org.springframework.beans.factory.annotation.Autowired;
034
035import java.util.Map;
036import java.util.concurrent.Callable;
037import java.util.concurrent.atomic.AtomicReference;
038
039public class ResourceCountCache implements IHasScheduledJobs {
040
041        private static final Logger ourLog = LoggerFactory.getLogger(ResourceCountCache.class);
042        private static Long ourNowForUnitTest;
043        private final Callable<Map<String, Long>> myFetcher;
044        private volatile long myCacheMillis;
045        private AtomicReference<Map<String, Long>> myCapabilityStatement = new AtomicReference<>();
046        private long myLastFetched;
047
048        /**
049         * Constructor
050         */
051        public ResourceCountCache(Callable<Map<String, Long>> theFetcher) {
052                myFetcher = theFetcher;
053        }
054
055        public synchronized void clear() {
056                ourLog.info("Clearing cache");
057                myCapabilityStatement.set(null);
058                myLastFetched = 0;
059        }
060
061        public synchronized Map<String, Long> get() {
062                return myCapabilityStatement.get();
063        }
064
065        private Map<String, Long> refresh() {
066                Map<String, Long> retVal;
067                try {
068                        retVal = myFetcher.call();
069                } catch (Exception e) {
070                        throw new InternalErrorException(Msg.code(799) + e);
071                }
072
073                myCapabilityStatement.set(retVal);
074                myLastFetched = now();
075                return retVal;
076        }
077
078        public void setCacheMillis(long theCacheMillis) {
079                myCacheMillis = theCacheMillis;
080        }
081
082        public void update() {
083                if (myCacheMillis > 0) {
084                        long now = now();
085                        long expiry = now - myCacheMillis;
086                        if (myLastFetched < expiry) {
087                                refresh();
088                        }
089                }
090        }
091
092        @Override
093        public void scheduleJobs(ISchedulerService theSchedulerService) {
094                ScheduledJobDefinition jobDetail = new ScheduledJobDefinition();
095                jobDetail.setId(getClass().getName());
096                jobDetail.setJobClass(Job.class);
097                theSchedulerService.scheduleLocalJob(10 * DateUtils.MILLIS_PER_MINUTE, jobDetail);
098        }
099
100        public static class Job implements HapiJob {
101                @Autowired
102                private ResourceCountCache myTarget;
103
104                @Override
105                public void execute(JobExecutionContext theContext) {
106                        myTarget.update();
107                }
108        }
109
110        private static long now() {
111                if (ourNowForUnitTest != null) {
112                        return ourNowForUnitTest;
113                }
114                return System.currentTimeMillis();
115        }
116
117        @VisibleForTesting
118        static void setNowForUnitTest(Long theNowForUnitTest) {
119                ourNowForUnitTest = theNowForUnitTest;
120        }
121}