Shutdown.java

// Copyright 2016 Twitter. All rights reserved.
//
// Licensed 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.twitter.heron.spi.utils;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.logging.Logger;

public class Shutdown {
  private static final Logger LOG = Logger.getLogger(Shutdown.class.getName());
  private final Lock lock = new ReentrantLock();
  private final Condition terminateCondition = lock.newCondition();
  private boolean terminated = false;

  public void await() {
    try {
      lock.lock();
      while (!terminated) {
        terminateCondition.await();
      }
      lock.unlock();
    } catch (InterruptedException e) {
      LOG.info("Process received interruption, terminating...");
      lock.unlock();
    }
  }

  public void terminate() {
    lock.lock();
    terminated = true;
    terminateCondition.signal();
    lock.unlock();
  }
}