/* Licensed to Diennea S.r.l. under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. Diennea S.r.l. licenses this file to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ package blazingcache.client.impl; import java.util.HashMap; import java.util.Map; import java.util.concurrent.atomic.AtomicInteger; import java.util.concurrent.locks.ReentrantLock; import java.util.concurrent.locks.ReentrantReadWriteLock; import java.util.logging.Level; import java.util.logging.Logger; /** * Handle locks by key * * @author enrico.olivelli */ public class LocalLockManager { private static final Logger LOGGER = Logger.getLogger(LocalLockManager.class.getName()); private static final boolean ENABLE_LOCAL_LOCKS = Boolean.parseBoolean(System.getProperty("blazingcache.client.enablelocallocks", "true")); private ReentrantReadWriteLock makeLock() { return new ReentrantReadWriteLock(); } private final ReentrantLock generalLock = new ReentrantLock(true); private final Map<String, ReentrantReadWriteLock> liveLocks = new HashMap<>(); private final Map<String, AtomicInteger> locksCounter = new HashMap<>(); private ReentrantReadWriteLock makeLockForKey(String key) { ReentrantReadWriteLock lock; generalLock.lock(); try { lock = liveLocks.get(key); if (lock == null) { lock = makeLock(); liveLocks.put(key, lock); locksCounter.put(key, new AtomicInteger(1)); } else { locksCounter.get(key).incrementAndGet(); } } finally { generalLock.unlock(); } return lock; } private ReentrantReadWriteLock returnLockForKey(String key) throws IllegalStateException { ReentrantReadWriteLock lock; generalLock.lock(); try { lock = liveLocks.get(key); if (lock == null) { LOGGER.log(Level.SEVERE, "no lock object exists for key {0}", key); throw new IllegalStateException("no lock object exists for key " + key); } int actualCount = locksCounter.get(key).decrementAndGet(); if (actualCount == 0) { liveLocks.remove(key); locksCounter.remove(key); } } finally { generalLock.unlock(); } return lock; } public ReentrantReadWriteLock acquireWriteLockForKey(String key) { if (!ENABLE_LOCAL_LOCKS) { return null; } ReentrantReadWriteLock lock = makeLockForKey(key); lock.writeLock().lock(); return lock; } public void releaseWriteLockForKey(String key, ReentrantReadWriteLock lockStamp) { if (!ENABLE_LOCAL_LOCKS) { return; } ReentrantReadWriteLock lock = returnLockForKey(key); lock.writeLock().unlock(); } public ReentrantReadWriteLock acquireReadLockForKey(String key) { if (!ENABLE_LOCAL_LOCKS) { return null; } ReentrantReadWriteLock lock = makeLockForKey(key); lock.readLock().lock(); return lock; } public void releaseReadLockForKey(String key, ReentrantReadWriteLock lockStamp) { if (!ENABLE_LOCAL_LOCKS) { return; } ReentrantReadWriteLock lock = returnLockForKey(key); lock.readLock().unlock(); } }