Java example source code file (SettableFutureTest.java)

This example Java source code file (SettableFutureTest.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

cancellationexception, exception, executionexception, expected, foo, foochild, listenablefuturetester, nullpointerexception, override, settablefuture, settablefuturetest, testcase, threading, threads, timeoutexception

The SettableFutureTest.java Java example source code

/*
 * Copyright (C) 2009 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;

import junit.framework.TestCase;

import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

/**
 * Test cases for {@link SettableFuture}.
 *
 * @author Sven Mawson
 */
public class SettableFutureTest extends TestCase {

  private SettableFuture<String> future;
  private ListenableFutureTester tester;

  @Override
  protected void setUp() throws Exception {
    super.setUp();

    future = SettableFuture.create();
    tester = new ListenableFutureTester(future);
    tester.setUp();
  }

  public void testDefaultState() throws Exception {
    try {
      future.get(5, TimeUnit.MILLISECONDS);
      fail();
    } catch (TimeoutException expected) {}
  }

  public void testSetValue() throws Exception {
    assertTrue(future.set("value"));
    tester.testCompletedFuture("value");
  }

  public void testSetFailure() throws Exception {
    assertTrue(future.setException(new Exception("failure")));
    tester.testFailedFuture("failure");
  }

  public void testSetFailureNull() throws Exception {
    try {
      future.setException(null);
      fail();
    } catch (NullPointerException expected) {
    }
    assertFalse(future.isDone());
    assertTrue(future.setException(new Exception("failure")));
    tester.testFailedFuture("failure");
  }

  public void testCancel() throws Exception {
    assertTrue(future.cancel(true));
    tester.testCancelledFuture();
  }

  /** Tests the initial state of the future. */
  public void testCreate() throws Exception {
    SettableFuture<Integer> future = SettableFuture.create();
    assertFalse(future.isDone());
    assertFalse(future.isCancelled());
  }

  public void testSetValue_simpleThreaded() throws Exception {
    SettableFuture<Integer> future = SettableFuture.create();
    assertTrue(future.set(42));
    // Later attempts to set the future should return false.
    assertFalse(future.set(23));
    assertFalse(future.setException(new Exception("bar")));
    assertFalse(future.setFuture(SettableFuture.<Integer>create()));
    // Check that the future has been set properly.
    assertTrue(future.isDone());
    assertFalse(future.isCancelled());
    assertEquals(42, (int) future.get());
  }

  public void testSetException() throws Exception {
    SettableFuture<Object> future = SettableFuture.create();
    Exception e = new Exception("foobarbaz");
    assertTrue(future.setException(e));
    // Later attempts to set the future should return false.
    assertFalse(future.set(23));
    assertFalse(future.setException(new Exception("quux")));
    assertFalse(future.setFuture(SettableFuture.create()));
    // Check that the future has been set properly.
    assertTrue(future.isDone());
    assertFalse(future.isCancelled());
    try {
      future.get();
      fail("Expected ExecutionException");
    } catch (ExecutionException ee) {
      assertSame(e, ee.getCause());
    }
  }

  public void testSetFuture() throws Exception {
    SettableFuture<String> future = SettableFuture.create();
    SettableFuture<String> nested = SettableFuture.create();
    assertTrue(future.setFuture(nested));
    // Later attempts to set the future should return false.
    assertFalse(future.set("x"));
    assertFalse(future.setException(new Exception("bar")));
    assertFalse(future.setFuture(SettableFuture.<String>create()));
    // Check that the future has been set properly.
    assertFalse(future.isDone());
    assertFalse(future.isCancelled());
    try {
      future.get(0, TimeUnit.MILLISECONDS);
      fail("Expected TimeoutException");
    } catch (TimeoutException expected) { /* expected */ }
    nested.set("foo");
    assertTrue(future.isDone());
    assertFalse(future.isCancelled());
    assertEquals("foo", future.get());
  }

  private static class Foo {}
  private static class FooChild extends Foo {}

  public void testSetFuture_genericsHierarchy() throws Exception {
    SettableFuture<Foo> future = SettableFuture.create();
    SettableFuture<FooChild> nested = SettableFuture.create();
    assertTrue(future.setFuture(nested));
    // Later attempts to set the future should return false.
    assertFalse(future.set(new Foo()));
    assertFalse(future.setException(new Exception("bar")));
    assertFalse(future.setFuture(SettableFuture.<Foo>create()));
    // Check that the future has been set properly.
    assertFalse(future.isDone());
    assertFalse(future.isCancelled());
    try {
      future.get(0, TimeUnit.MILLISECONDS);
      fail("Expected TimeoutException");
    } catch (TimeoutException expected) { /* expected */ }
    FooChild value = new FooChild();
    nested.set(value);
    assertTrue(future.isDone());
    assertFalse(future.isCancelled());
    assertSame(value, future.get());
  }

  public void testCancel_innerCancelsAsync() throws Exception {
    SettableFuture<Object> async = SettableFuture.create();
    SettableFuture<Object> inner = SettableFuture.create();
    async.setFuture(inner);
    inner.cancel(true);
    assertTrue(async.isCancelled());
    try {
      async.get();
      fail("Expected CancellationException");
    } catch (CancellationException expected) { /* expected */ }
  }

  public void testCancel_resultCancelsInner_interrupted() throws Exception {
    SettableFuture<Object> async = SettableFuture.create();
    SettableFuture<Object> inner = SettableFuture.create();
    async.setFuture(inner);
    async.cancel(true);
    assertTrue(inner.isCancelled());
    assertTrue(inner.wasInterrupted());
    try {
      inner.get();
      fail("Expected CancellationException");
    } catch (CancellationException expected) { /* expected */ }
  }

  public void testCancel_resultCancelsInner() throws Exception {
    SettableFuture<Object> async = SettableFuture.create();
    SettableFuture<Object> inner = SettableFuture.create();
    async.setFuture(inner);
    async.cancel(false);
    assertTrue(inner.isCancelled());
    assertFalse(inner.wasInterrupted());
    try {
      inner.get();
      fail("Expected CancellationException");
    } catch (CancellationException expected) { /* expected */ }
  }

  public void testCancel_beforeSet() throws Exception {
    SettableFuture<Object> async = SettableFuture.create();
    async.cancel(true);
    assertFalse(async.set(42));
  }

  public void testCancel_multipleBeforeSetFuture_noInterruptFirst() throws Exception {
    SettableFuture<Object> async = SettableFuture.create();
    async.cancel(false);
    async.cancel(true);
    SettableFuture<Object> inner = SettableFuture.create();
    assertFalse(async.setFuture(inner));
    assertTrue(inner.isCancelled());
    assertFalse(inner.wasInterrupted());
  }

  public void testCancel_multipleBeforeSetFuture_interruptFirst() throws Exception {
    SettableFuture<Object> async = SettableFuture.create();
    async.cancel(true);
    async.cancel(false);
    SettableFuture<Object> inner = SettableFuture.create();
    assertFalse(async.setFuture(inner));
    assertTrue(inner.isCancelled());
    assertTrue(inner.wasInterrupted());
  }
}