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A common base library for Apache Accumulo servers.

There is a newer version: 3.0.0

/*
 * 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");
  }

}