001// --------------------------------------------------------------------------------
002// Copyright 2002-2024 Echo Three, LLC
003//
004// Licensed under the Apache License, Version 2.0 (the "License");
005// you may not use this file except in compliance with the License.
006// You may obtain a copy of the License at
007//
008//     http://www.apache.org/licenses/LICENSE-2.0
009//
010// Unless required by applicable law or agreed to in writing, software
011// distributed under the License is distributed on an "AS IS" BASIS,
012// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013// See the License for the specific language governing permissions and
014// limitations under the License.
015// --------------------------------------------------------------------------------
016
017package com.echothree.util.server.persistence;
018
019import org.apache.commons.logging.Log;
020import org.apache.commons.logging.LogFactory;
021
022public class ThreadCaches {
023    
024    private static Log log = LogFactory.getLog(ThreadCaches.class);
025    private static final ThreadLocal<Caches> cacheses = new ThreadLocal<>();
026
027    private ThreadCaches() {}
028
029    public static Caches currentCaches() {
030        Caches caches = cacheses.get();
031        
032        if(caches == null) {
033            caches = CachesFactory.getInstance().getCaches();
034            cacheses.set(caches);
035            
036            if(PersistenceDebugFlags.LogThreads) {
037                log.info("Created Caches for Thread " + Thread.currentThread().getName());
038            }
039        }
040        
041        return caches;
042    }
043
044    static class PreservedCaches {
045        private Caches caches;
046
047        private PreservedCaches(Caches caches) {
048            this.caches = caches;
049        }
050    }
051
052    // Utilize via ThreadUtils
053    static ThreadCaches.PreservedCaches preserve() {
054        Caches caches = cacheses.get();
055
056        if(caches != null) {
057            cacheses.remove();
058
059            if(PersistenceDebugFlags.LogThreads) {
060                log.info("Preserved Caches for Thread " + Thread.currentThread().getName());
061            }
062        }
063
064        return new ThreadCaches.PreservedCaches(caches);
065    }
066
067    // Utilize via ThreadUtils
068    static void restore(ThreadCaches.PreservedCaches preservedCaches) {
069        var caches = preservedCaches.caches;
070
071        if(caches != null) {
072            cacheses.set(caches);
073
074            if(PersistenceDebugFlags.LogThreads) {
075                log.info("Restored Caches for Thread " + Thread.currentThread().getName());
076            }
077        }
078    }
079
080    // Utilize via ThreadUtils
081    public static void close() {
082        Caches caches = cacheses.get();
083        
084        if(caches != null) {
085            caches.close();
086            cacheses.remove();
087            
088            if(PersistenceDebugFlags.LogThreads) {
089                log.info("Closed Caches for Thread " + Thread.currentThread().getName());
090            }
091        }
092    }
093    
094}