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Java example source code file (MonitorTestCase.java)

This example Java source code file (MonitorTestCase.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

exception, illegalmonitorstateexception, inhibit, monitortestcase, nullpointertester, override, string, teardownstack, testguard, testthread, threading, threads, util

The MonitorTestCase.java Java example source code

/*
 * Copyright (C) 2010 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 com.google.common.testing.NullPointerTester;
import com.google.common.testing.TearDownStack;

import junit.framework.TestCase;

import java.util.Random;
import java.util.concurrent.TimeUnit;

/**
 * Tests for {@link Monitor}, either interruptible or uninterruptible.
 *
 * @author Justin T. Sampson
 */

public abstract class MonitorTestCase extends TestCase {

  public class TestGuard extends Monitor.Guard {
    private volatile boolean satisfied;

    public TestGuard(boolean satisfied) {
      super(MonitorTestCase.this.monitor);
      this.satisfied = satisfied;
    }

    @Override public boolean isSatisfied() {
      return this.satisfied;
    }

    public void setSatisfied(boolean satisfied) {
      this.satisfied = satisfied;
    }
  }

  private final boolean interruptible;
  private Monitor monitor;
  private final TearDownStack tearDownStack = new TearDownStack(true);
  private TestThread<Monitor> thread1;
  private TestThread<Monitor> thread2;

  protected MonitorTestCase(boolean interruptible) {
    this.interruptible = interruptible;
  }

  @Override protected final void setUp() throws Exception {
    boolean fair = new Random().nextBoolean();
    monitor = new Monitor(fair);
    tearDownStack.addTearDown(thread1 = new TestThread<Monitor>(monitor, "TestThread #1"));
    tearDownStack.addTearDown(thread2 = new TestThread<Monitor>(monitor, "TestThread #2"));
  }

  @Override protected final void tearDown() {
    tearDownStack.runTearDown();
  }

  private String enter() {
    return interruptible ? "enterInterruptibly" : "enter";
  }

  private String tryEnter() {
    return "tryEnter";
  }

  private String enterIf() {
    return interruptible ? "enterIfInterruptibly" : "enterIf";
  }

  private String tryEnterIf() {
    return "tryEnterIf";
  }

  private String enterWhen() {
    return interruptible ? "enterWhen" : "enterWhenUninterruptibly";
  }

  private String waitFor() {
    return interruptible ? "waitFor" : "waitForUninterruptibly";
  }

  private String leave() {
    return "leave";
  }

  public final void testMutualExclusion() throws Exception {
    thread1.callAndAssertReturns(enter());
    thread2.callAndAssertBlocks(enter());
    thread1.callAndAssertReturns(leave());
    thread2.assertPriorCallReturns(enter());
  }

  public final void testTryEnter() throws Exception {
    thread1.callAndAssertReturns(true, tryEnter());
    thread2.callAndAssertReturns(false, tryEnter());
    thread1.callAndAssertReturns(true, tryEnter());
    thread2.callAndAssertReturns(false, tryEnter());
    thread1.callAndAssertReturns(leave());
    thread2.callAndAssertReturns(false, tryEnter());
    thread1.callAndAssertReturns(leave());
    thread2.callAndAssertReturns(true, tryEnter());
  }

  public final void testSystemStateMethods() throws Exception {
    checkSystemStateMethods(0);
    thread1.callAndAssertReturns(enter());
    checkSystemStateMethods(1);
    thread1.callAndAssertReturns(enter());
    checkSystemStateMethods(2);
    thread1.callAndAssertReturns(leave());
    checkSystemStateMethods(1);
    thread1.callAndAssertReturns(leave());
    checkSystemStateMethods(0);
  }

  private void checkSystemStateMethods(int enterCount) throws Exception {
    thread1.callAndAssertReturns(enterCount != 0, "isOccupied");
    thread1.callAndAssertReturns(enterCount != 0, "isOccupiedByCurrentThread");
    thread1.callAndAssertReturns(enterCount, "getOccupiedDepth");

    thread2.callAndAssertReturns(enterCount != 0, "isOccupied");
    thread2.callAndAssertReturns(false, "isOccupiedByCurrentThread");
    thread2.callAndAssertReturns(0, "getOccupiedDepth");
  }

  public final void testEnterWhen_initiallyTrue() throws Exception {
    TestGuard guard = new TestGuard(true);
    thread1.callAndAssertReturns(enterWhen(), guard);
  }

  public final void testEnterWhen_initiallyFalse() throws Exception {
    TestGuard guard = new TestGuard(false);
    thread1.callAndAssertWaits(enterWhen(), guard);
    monitor.enter();
    guard.setSatisfied(true);
    monitor.leave();
    thread1.assertPriorCallReturns(enterWhen());
  }

  public final void testEnterWhen_alreadyOccupied() throws Exception {
    TestGuard guard = new TestGuard(true);
    thread2.callAndAssertReturns(enter());
    thread1.callAndAssertBlocks(enterWhen(), guard);
    thread2.callAndAssertReturns(leave());
    thread1.assertPriorCallReturns(enterWhen());
  }

  public final void testEnterIf_initiallyTrue() throws Exception {
    TestGuard guard = new TestGuard(true);
    thread1.callAndAssertReturns(true, enterIf(), guard);
    thread2.callAndAssertBlocks(enter());
  }

  public final void testEnterIf_initiallyFalse() throws Exception {
    TestGuard guard = new TestGuard(false);
    thread1.callAndAssertReturns(false, enterIf(), guard);
    thread2.callAndAssertReturns(enter());
  }

  public final void testEnterIf_alreadyOccupied() throws Exception {
    TestGuard guard = new TestGuard(true);
    thread2.callAndAssertReturns(enter());
    thread1.callAndAssertBlocks(enterIf(), guard);
    thread2.callAndAssertReturns(leave());
    thread1.assertPriorCallReturns(true, enterIf());
  }

  public final void testTryEnterIf_initiallyTrue() throws Exception {
    TestGuard guard = new TestGuard(true);
    thread1.callAndAssertReturns(true, tryEnterIf(), guard);
    thread2.callAndAssertBlocks(enter());
  }

  public final void testTryEnterIf_initiallyFalse() throws Exception {
    TestGuard guard = new TestGuard(false);
    thread1.callAndAssertReturns(false, tryEnterIf(), guard);
    thread2.callAndAssertReturns(enter());
  }

  public final void testTryEnterIf_alreadyOccupied() throws Exception {
    TestGuard guard = new TestGuard(true);
    thread2.callAndAssertReturns(enter());
    thread1.callAndAssertReturns(false, tryEnterIf(), guard);
  }

  public final void testWaitFor_initiallyTrue() throws Exception {
    TestGuard guard = new TestGuard(true);
    thread1.callAndAssertReturns(enter());
    thread1.callAndAssertReturns(waitFor(), guard);
  }

  public final void testWaitFor_initiallyFalse() throws Exception {
    TestGuard guard = new TestGuard(false);
    thread1.callAndAssertReturns(enter());
    thread1.callAndAssertWaits(waitFor(), guard);
    monitor.enter();
    guard.setSatisfied(true);
    monitor.leave();
    thread1.assertPriorCallReturns(waitFor());
  }

  public final void testWaitFor_withoutEnter() throws Exception {
    TestGuard guard = new TestGuard(true);
    thread1.callAndAssertThrows(IllegalMonitorStateException.class, waitFor(), guard);
  }

  public void testNulls() {
    monitor.enter();  // Inhibit IllegalMonitorStateException
    new NullPointerTester()
        .setDefault(TimeUnit.class, TimeUnit.SECONDS)
        .setDefault(Monitor.Guard.class, new TestGuard(true))
        .testAllPublicInstanceMethods(monitor);
  }

  // TODO: Test enter(long, TimeUnit).
  // TODO: Test enterWhen(Guard, long, TimeUnit).
  // TODO: Test enterIf(Guard, long, TimeUnit).
  // TODO: Test waitFor(Guard, long, TimeUnit).
  // TODO: Test getQueueLength().
  // TODO: Test hasQueuedThreads().
  // TODO: Test getWaitQueueLength(Guard).
  // TODO: Test automatic signaling before leave, waitFor, and reentrant enterWhen.
  // TODO: Test blocking to re-enter monitor after being signaled.
  // TODO: Test interrupts with both interruptible and uninterruptible monitor.
  // TODO: Test multiple waiters: If guard is still satisfied, signal next waiter.
  // TODO: Test multiple waiters: If guard is no longer satisfied, do not signal next waiter.

}

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