library/src/main/java/org/apache/apex/malhar/lib/appdata/QueueUtils.java

/**
 * 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 com.datatorrent.lib.appdata;

/**
 * @since 3.3.0
 */
public class QueueUtils
{
  /**
   * This class should not be instantiated.
   * @since 3.0.0
 */
  private QueueUtils()
  {
    //Do nothing
  }

  public static class ConditionBarrier
  {
    private boolean locked = false;
    private final Object lock = new Object();

    public ConditionBarrier()
    {
    }

    public void lock()
    {
      synchronized (lock) {
        locked = true;
      }
    }

    public void unlock()
    {
      synchronized (lock) {
        locked = false;
        lock.notifyAll();
      }
    }

    public void gate()
    {
      synchronized (lock) {
        while (locked) {
          try {
            lock.wait();
          } catch (InterruptedException ex) {
            //Do nothing
          }
        }
      }
    }
  }
}