alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Java example source code file (MockFutureListener.java)

This example Java source code file (MockFutureListener.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

beta, countdownlatch, exception, executionexception, gwtincompatible, listenablefuture, mockfuturelistener, override, runnable, this, threading, threads, throwable

The MockFutureListener.java Java example source code

/*
 * Copyright (C) 2008 The Guava Authors
 *
 * 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.google.common.util.concurrent.testing;

import static com.google.common.util.concurrent.MoreExecutors.directExecutor;

import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.util.concurrent.ListenableFuture;

import junit.framework.Assert;

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

/**
 * A simple mock implementation of {@code Runnable} that can be used for
 * testing ListenableFutures.
 *
 * @author Nishant Thakkar
 * @since 10.0
 */
@Beta
@GwtIncompatible
public class MockFutureListener implements Runnable {
  private final CountDownLatch countDownLatch;
  private final ListenableFuture<?> future;

  public MockFutureListener(ListenableFuture<?> future) {
    this.countDownLatch = new CountDownLatch(1);
    this.future = future;

    future.addListener(this, directExecutor());
  }

  @Override
  public void run() {
    countDownLatch.countDown();
  }

  /**
   * Verify that the listener completes in a reasonable amount of time, and
   * Asserts that the future returns the expected data.
   * @throws Throwable if the listener isn't called or if it resulted in a
   *     throwable or if the result doesn't match the expected value.
   */
  public void assertSuccess(Object expectedData) throws Throwable {
    // Verify that the listener executed in a reasonable amount of time.
    Assert.assertTrue(countDownLatch.await(1L, TimeUnit.SECONDS));

    try {
      Assert.assertEquals(expectedData, future.get());
    } catch (ExecutionException e) {
      throw e.getCause();
    }
  }

  /**
   * Verify that the listener completes in a reasonable amount of time, and
   * Asserts that the future throws an {@code ExecutableException} and that the
   * cause of the {@code ExecutableException} is {@code expectedCause}.
   */
  public void assertException(Throwable expectedCause) throws Exception {
    // Verify that the listener executed in a reasonable amount of time.
    Assert.assertTrue(countDownLatch.await(1L, TimeUnit.SECONDS));

    try {
      future.get();
      Assert.fail("This call was supposed to throw an ExecutionException");
    } catch (ExecutionException expected) {
      Assert.assertSame(expectedCause, expected.getCause());
    }
  }

  public void assertTimeout() throws Exception {
    // Verify that the listener does not get called in a reasonable amount of
    // time.
    Assert.assertFalse(countDownLatch.await(1L, TimeUnit.SECONDS));
  }
}

Other Java examples (source code examples)

Here is a short list of links related to this Java MockFutureListener.java source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.