/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF 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 org.apache.accumulo.server.zookeeper; import static java.nio.charset.StandardCharsets.UTF_8; import java.util.concurrent.TimeUnit; import java.util.concurrent.locks.Lock; import org.apache.accumulo.fate.zookeeper.DistributedReadWriteLock; import org.apache.zookeeper.KeeperException; public class ZooQueueLock extends org.apache.accumulo.fate.zookeeper.ZooQueueLock { public ZooQueueLock(String path, boolean ephemeral) throws KeeperException, InterruptedException { super(ZooReaderWriter.getInstance(), path, ephemeral); } public static void main(String args[]) throws InterruptedException, KeeperException { ZooQueueLock lock = new ZooQueueLock("/lock", true); DistributedReadWriteLock rlocker = new DistributedReadWriteLock(lock, "reader".getBytes(UTF_8)); DistributedReadWriteLock wlocker = new DistributedReadWriteLock(lock, "wlocker".getBytes(UTF_8)); final Lock readLock = rlocker.readLock(); readLock.lock(); final Lock readLock2 = rlocker.readLock(); readLock2.lock(); final Lock writeLock = wlocker.writeLock(); if (writeLock.tryLock(100, TimeUnit.MILLISECONDS)) throw new RuntimeException("Write lock achieved during read lock!"); readLock.unlock(); readLock2.unlock(); writeLock.lock(); if (readLock.tryLock(100, TimeUnit.MILLISECONDS)) throw new RuntimeException("Read lock achieved during write lock!"); final Lock writeLock2 = DistributedReadWriteLock.recoverLock(lock, "wlocker".getBytes(UTF_8)); writeLock2.unlock(); readLock.lock(); System.out.println("success"); } }