CountDownSubscriberListener.java

Go to the documentation of this file.

/*
 * Copyright (C) 2011 Google Inc.
 * 
 * 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 org.ros.node.topic;

import org.ros.internal.node.topic.PublisherIdentifier;

import org.ros.internal.node.CountDownRegistrantListener;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

public class CountDownSubscriberListener<T> extends CountDownRegistrantListener<Subscriber<T>>
    implements SubscriberListener<T> {

  private final CountDownLatch shutdownLatch;
  private final CountDownLatch newPublisherLatch;

  public static <T> CountDownSubscriberListener<T> newDefault() {
    return newFromCounts(1, 1, 1, 1, 1);
  }

  public static <T> CountDownSubscriberListener<T> newFromCounts(
      int masterRegistrationSuccessCount, int masterRegistrationFailureCount,
      int masterUnregistrationSuccessCount, int masterUnregistrationFailureCount,
      int newSubscriberCount) {
    return new CountDownSubscriberListener<T>(new CountDownLatch(masterRegistrationSuccessCount),
        new CountDownLatch(masterRegistrationFailureCount), new CountDownLatch(
            masterUnregistrationSuccessCount),
        new CountDownLatch(masterUnregistrationFailureCount),
        new CountDownLatch(newSubscriberCount));
  }

  private CountDownSubscriberListener(CountDownLatch masterRegistrationSuccessLatch,
      CountDownLatch masterRegistrationFailureLatch,
      CountDownLatch masterUnregistrationSuccessLatch,
      CountDownLatch masterUnregistrationFailureLatch, CountDownLatch newPublisherLatch) {
    super(masterRegistrationSuccessLatch, masterRegistrationFailureLatch,
        masterUnregistrationSuccessLatch, masterUnregistrationFailureLatch);
    this.newPublisherLatch = newPublisherLatch;
    shutdownLatch = new CountDownLatch(1);
  }

  @Override
  public void onNewPublisher(Subscriber<T> subscriber, PublisherIdentifier publisherIdentifier) {
    newPublisherLatch.countDown();
  }

  @Override
  public void onShutdown(Subscriber<T> subscriber) {
    shutdownLatch.countDown();
  }

  public void awaitNewPublisher() throws InterruptedException {
    newPublisherLatch.await();
  }

  public boolean awaitNewPublisher(long timeout, TimeUnit unit) throws InterruptedException {
    return newPublisherLatch.await(timeout, unit);
  }

  public void awaitShutdown() throws InterruptedException {
    shutdownLatch.await();
  }

  public boolean awaitShutdown(long timeout, TimeUnit unit) throws InterruptedException {
    return shutdownLatch.await(timeout, unit);
  }
}