guava-tests/test/com/google/common/eventbus/EventBusTest.java - platform/external/guava - Git at Google

 /*
  * Copyright (C) 2007 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.eventbus;

 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Lists;

 import junit.framework.TestCase;

 import java.util.Collection;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;

 /**
  * Test case for {@link EventBus}.
  *
  * @author Cliff Biffle
  */
 public class EventBusTest extends TestCase {
   private static final String EVENT = "Hello";
   private static final String BUS_IDENTIFIER = "test-bus";

   private EventBus bus;

   @Override protected void setUp() throws Exception {
     super.setUp();
     bus = new EventBus(BUS_IDENTIFIER);
   }

   public void testBasicCatcherDistribution() {
     StringCatcher catcher = new StringCatcher();
     bus.register(catcher);
     bus.post(EVENT);

     List<String> events = catcher.getEvents();
     assertEquals("Only one event should be delivered.", 1, events.size());
     assertEquals("Correct string should be delivered.", EVENT, events.get(0));
   }

   /**
    * Tests that events are distributed to any subscribers to their type or any
    * supertype, including interfaces and superclasses.
    *
    * Also checks delivery ordering in such cases.
    */
   public void testPolymorphicDistribution() {
     // Three catchers for related types String, Object, and Comparable<?>.
     // String isa Object
     // String isa Comparable<?>
     // Comparable<?> isa Object
     StringCatcher stringCatcher = new StringCatcher();

     final List<Object> objectEvents = Lists.newArrayList();
     Object objCatcher = new Object() {
       @SuppressWarnings("unused")
       @Subscribe public void eat(Object food) {
         objectEvents.add(food);
       }
     };

     final List<Comparable<?>> compEvents = Lists.newArrayList();
     Object compCatcher = new Object() {
       @SuppressWarnings("unused")
       @Subscribe public void eat(Comparable<?> food) {
         compEvents.add(food);
       }
     };
     bus.register(stringCatcher);
     bus.register(objCatcher);
     bus.register(compCatcher);

     // Two additional event types: Object and Comparable<?> (played by Integer)
     final Object OBJ_EVENT = new Object();
     final Object COMP_EVENT = new Integer(6);

     bus.post(EVENT);
     bus.post(OBJ_EVENT);
     bus.post(COMP_EVENT);

     // Check the StringCatcher...
     List<String> stringEvents = stringCatcher.getEvents();
     assertEquals("Only one String should be delivered.",
         1, stringEvents.size());
     assertEquals("Correct string should be delivered.",
         EVENT, stringEvents.get(0));

     // Check the Catcher<Object>...
     assertEquals("Three Objects should be delivered.",
         3, objectEvents.size());
     assertEquals("String fixture must be first object delivered.",
         EVENT, objectEvents.get(0));
     assertEquals("Object fixture must be second object delivered.",
         OBJ_EVENT, objectEvents.get(1));
     assertEquals("Comparable fixture must be thirdobject delivered.",
         COMP_EVENT, objectEvents.get(2));

     // Check the Catcher<Comparable<?>>...
     assertEquals("Two Comparable<?>s should be delivered.",
         2, compEvents.size());
     assertEquals("String fixture must be first comparable delivered.",
         EVENT, compEvents.get(0));
     assertEquals("Comparable fixture must be second comparable delivered.",
         COMP_EVENT, compEvents.get(1));
   }

   public void testSubscriberThrowsException() throws Exception{
     final RecordingSubscriberExceptionHandler handler =
         new RecordingSubscriberExceptionHandler();
     final EventBus eventBus = new EventBus(handler);
     final RuntimeException exception =
         new RuntimeException("but culottes have a tendancy to ride up!");
     final Object subscriber = new Object() {
       @Subscribe
       public void throwExceptionOn(String message) {
         throw exception;
       }
     };
     eventBus.register(subscriber);
     eventBus.post(EVENT);

     assertEquals("Cause should be available.",
         exception, handler.exception);
     assertEquals("EventBus should be available.",
         eventBus, handler.context.getEventBus());
     assertEquals("Event should be available.",
         EVENT,
         handler.context.getEvent());
     assertEquals("Subscriber should be available.",
         subscriber, handler.context.getSubscriber());
     assertEquals("Method should be available.",
         subscriber.getClass().getMethod("throwExceptionOn", String.class),
         handler.context.getSubscriberMethod());
   }

   public void testSubscriberThrowsExceptionHandlerThrowsException() throws Exception{
     final EventBus eventBus = new EventBus(new SubscriberExceptionHandler() {
       @Override
       public void handleException(Throwable exception,
           SubscriberExceptionContext context) {
         throw new RuntimeException();
       }
     });
     final Object subscriber = new Object() {
       @Subscribe
       public void throwExceptionOn(String message) {
         throw new RuntimeException();
       }
     };
     eventBus.register(subscriber);
     try {
       eventBus.post(EVENT);
     } catch (RuntimeException e) {
       fail("Exception should not be thrown.");
     }
   }

   public void testDeadEventForwarding() {
     GhostCatcher catcher = new GhostCatcher();
     bus.register(catcher);

     // A String -- an event for which noone has registered.
     bus.post(EVENT);

     List<DeadEvent> events = catcher.getEvents();
     assertEquals("One dead event should be delivered.", 1, events.size());
     assertEquals("The dead event should wrap the original event.",
         EVENT, events.get(0).getEvent());
   }

   public void testDeadEventPosting() {
     GhostCatcher catcher = new GhostCatcher();
     bus.register(catcher);

     bus.post(new DeadEvent(this, EVENT));

     List<DeadEvent> events = catcher.getEvents();
     assertEquals("The explicit DeadEvent should be delivered.",
         1, events.size());
     assertEquals("The dead event must not be re-wrapped.",
         EVENT, events.get(0).getEvent());
   }

   public void testFlattenHierarchy() {
     HierarchyFixture fixture = new HierarchyFixture();
     Set<Class<?>> hierarchy = bus.flattenHierarchy(fixture.getClass());

     assertEquals(5, hierarchy.size());
     assertContains(Object.class, hierarchy);
     assertContains(HierarchyFixtureInterface.class, hierarchy);
     assertContains(HierarchyFixtureSubinterface.class, hierarchy);
     assertContains(HierarchyFixtureParent.class, hierarchy);
     assertContains(HierarchyFixture.class, hierarchy);
   }

   public void testMissingSubscribe() {
     bus.register(new Object());
   }

   public void testUnregister() {
     StringCatcher catcher1 = new StringCatcher();
     StringCatcher catcher2 = new StringCatcher();
     try {
       bus.unregister(catcher1);
       fail("Attempting to unregister an unregistered object succeeded");
     } catch (IllegalArgumentException expected) {
       // OK.
     }

     bus.register(catcher1);
     bus.post(EVENT);
     bus.register(catcher2);
     bus.post(EVENT);

     List<String> expectedEvents = Lists.newArrayList();
     expectedEvents.add(EVENT);
     expectedEvents.add(EVENT);

     assertEquals("Two correct events should be delivered.",
                  expectedEvents, catcher1.getEvents());

     assertEquals("One correct event should be delivered.",
                  Lists.newArrayList(EVENT), catcher2.getEvents());

     bus.unregister(catcher1);
     bus.post(EVENT);

     assertEquals("Shouldn't catch any more events when unregistered.",
                  expectedEvents, catcher1.getEvents());
     assertEquals("Two correct events should be delivered.",
                  expectedEvents, catcher2.getEvents());

     try {
       bus.unregister(catcher1);
       fail("Attempting to unregister an unregistered object succeeded");
     } catch (IllegalArgumentException expected) {
       // OK.
     }

     bus.unregister(catcher2);
     bus.post(EVENT);
     assertEquals("Shouldn't catch any more events when unregistered.",
                  expectedEvents, catcher1.getEvents());
     assertEquals("Shouldn't catch any more events when unregistered.",
                  expectedEvents, catcher2.getEvents());
   }

   // NOTE: This test will always pass if register() is thread-safe but may also
   // pass if it isn't, though this is unlikely.

   public void testRegisterThreadSafety() throws Exception {
     List<StringCatcher> catchers = Lists.newCopyOnWriteArrayList();
     List<Future<?>> futures = Lists.newArrayList();
     ExecutorService executor = Executors.newFixedThreadPool(10);
     int numberOfCatchers = 10000;
     for (int i = 0; i < numberOfCatchers; i++) {
       futures.add(executor.submit(new Registrator(bus, catchers)));
     }
     for (int i = 0; i < numberOfCatchers; i++) {
       futures.get(i).get();
     }
     assertEquals("Unexpected number of catchers in the list",
         numberOfCatchers, catchers.size());
     bus.post(EVENT);
     List<String> expectedEvents = ImmutableList.of(EVENT);
     for (StringCatcher catcher : catchers) {
       assertEquals("One of the registered catchers did not receive an event.",
           expectedEvents, catcher.getEvents());
     }
   }

   private <T> void assertContains(T element, Collection<T> collection) {
     assertTrue("Collection must contain " + element,
         collection.contains(element));
   }

   /**
    * Records a thrown exception information.
    */
   private static final class RecordingSubscriberExceptionHandler
       implements SubscriberExceptionHandler {

     public SubscriberExceptionContext context;
     public Throwable exception;

     @Override
     public void handleException(Throwable exception,
         SubscriberExceptionContext context) {
       this.exception = exception;
       this.context = context;

     }
   }

   /**
    * Runnable which registers a StringCatcher on an event bus and adds it to a
    * list.
    */
   private static class Registrator implements Runnable {
     private final EventBus bus;
     private final List<StringCatcher> catchers;

     Registrator(EventBus bus, List<StringCatcher> catchers) {
       this.bus = bus;
       this.catchers = catchers;
     }

     @Override
     public void run() {
       StringCatcher catcher = new StringCatcher();
       bus.register(catcher);
       catchers.add(catcher);
     }
   }

   /**
    * A collector for DeadEvents.
    *
    * @author cbiffle
    *
    */
   public static class GhostCatcher {
     private List<DeadEvent> events = Lists.newArrayList();

     @Subscribe
     public void ohNoesIHaveDied(DeadEvent event) {
       events.add(event);
     }

     public List<DeadEvent> getEvents() {
       return events;
     }
   }

   public interface HierarchyFixtureInterface {
     // Exists only for hierarchy mapping; no members.
   }

   public interface HierarchyFixtureSubinterface
       extends HierarchyFixtureInterface {
     // Exists only for hierarchy mapping; no members.
   }

   public static class HierarchyFixtureParent
       implements HierarchyFixtureSubinterface {
     // Exists only for hierarchy mapping; no members.
   }

   public static class HierarchyFixture extends HierarchyFixtureParent {
     // Exists only for hierarchy mapping; no members.
   }

 }
	/*
	* Copyright (C) 2007 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.eventbus;

	import com.google.common.collect.ImmutableList;
	import com.google.common.collect.Lists;

	import junit.framework.TestCase;

	import java.util.Collection;
	import java.util.List;
	import java.util.Set;
	import java.util.concurrent.ExecutorService;
	import java.util.concurrent.Executors;
	import java.util.concurrent.Future;

	/**
	* Test case for {@link EventBus}.
	*
	* @author Cliff Biffle
	*/
	public class EventBusTest extends TestCase {
	private static final String EVENT = "Hello";
	private static final String BUS_IDENTIFIER = "test-bus";

	private EventBus bus;

	@Override protected void setUp() throws Exception {
	super.setUp();
	bus = new EventBus(BUS_IDENTIFIER);
	}

	public void testBasicCatcherDistribution() {
	StringCatcher catcher = new StringCatcher();
	bus.register(catcher);
	bus.post(EVENT);

	List<String> events = catcher.getEvents();
	assertEquals("Only one event should be delivered.", 1, events.size());
	assertEquals("Correct string should be delivered.", EVENT, events.get(0));
	}

	/**
	* Tests that events are distributed to any subscribers to their type or any
	* supertype, including interfaces and superclasses.
	*
	* Also checks delivery ordering in such cases.
	*/
	public void testPolymorphicDistribution() {
	// Three catchers for related types String, Object, and Comparable<?>.
	// String isa Object
	// String isa Comparable<?>
	// Comparable<?> isa Object
	StringCatcher stringCatcher = new StringCatcher();

	final List<Object> objectEvents = Lists.newArrayList();
	Object objCatcher = new Object() {
	@SuppressWarnings("unused")
	@Subscribe public void eat(Object food) {
	objectEvents.add(food);
	}
	};

	final List<Comparable<?>> compEvents = Lists.newArrayList();
	Object compCatcher = new Object() {
	@SuppressWarnings("unused")
	@Subscribe public void eat(Comparable<?> food) {
	compEvents.add(food);
	}
	};
	bus.register(stringCatcher);
	bus.register(objCatcher);
	bus.register(compCatcher);

	// Two additional event types: Object and Comparable<?> (played by Integer)
	final Object OBJ_EVENT = new Object();
	final Object COMP_EVENT = new Integer(6);

	bus.post(EVENT);
	bus.post(OBJ_EVENT);
	bus.post(COMP_EVENT);

	// Check the StringCatcher...
	List<String> stringEvents = stringCatcher.getEvents();
	assertEquals("Only one String should be delivered.",
	1, stringEvents.size());
	assertEquals("Correct string should be delivered.",
	EVENT, stringEvents.get(0));

	// Check the Catcher<Object>...
	assertEquals("Three Objects should be delivered.",
	3, objectEvents.size());
	assertEquals("String fixture must be first object delivered.",
	EVENT, objectEvents.get(0));
	assertEquals("Object fixture must be second object delivered.",
	OBJ_EVENT, objectEvents.get(1));
	assertEquals("Comparable fixture must be thirdobject delivered.",
	COMP_EVENT, objectEvents.get(2));

	// Check the Catcher<Comparable<?>>...
	assertEquals("Two Comparable<?>s should be delivered.",
	2, compEvents.size());
	assertEquals("String fixture must be first comparable delivered.",
	EVENT, compEvents.get(0));
	assertEquals("Comparable fixture must be second comparable delivered.",
	COMP_EVENT, compEvents.get(1));
	}

	public void testSubscriberThrowsException() throws Exception{
	final RecordingSubscriberExceptionHandler handler =
	new RecordingSubscriberExceptionHandler();
	final EventBus eventBus = new EventBus(handler);
	final RuntimeException exception =
	new RuntimeException("but culottes have a tendancy to ride up!");
	final Object subscriber = new Object() {
	@Subscribe
	public void throwExceptionOn(String message) {
	throw exception;
	}
	};
	eventBus.register(subscriber);
	eventBus.post(EVENT);

	assertEquals("Cause should be available.",
	exception, handler.exception);
	assertEquals("EventBus should be available.",
	eventBus, handler.context.getEventBus());
	assertEquals("Event should be available.",
	EVENT,
	handler.context.getEvent());
	assertEquals("Subscriber should be available.",
	subscriber, handler.context.getSubscriber());
	assertEquals("Method should be available.",
	subscriber.getClass().getMethod("throwExceptionOn", String.class),
	handler.context.getSubscriberMethod());
	}

	public void testSubscriberThrowsExceptionHandlerThrowsException() throws Exception{
	final EventBus eventBus = new EventBus(new SubscriberExceptionHandler() {
	@Override
	public void handleException(Throwable exception,
	SubscriberExceptionContext context) {
	throw new RuntimeException();
	}
	});
	final Object subscriber = new Object() {
	@Subscribe
	public void throwExceptionOn(String message) {
	throw new RuntimeException();
	}
	};
	eventBus.register(subscriber);
	try {
	eventBus.post(EVENT);
	} catch (RuntimeException e) {
	fail("Exception should not be thrown.");
	}
	}

	public void testDeadEventForwarding() {
	GhostCatcher catcher = new GhostCatcher();
	bus.register(catcher);

	// A String -- an event for which noone has registered.
	bus.post(EVENT);

	List<DeadEvent> events = catcher.getEvents();
	assertEquals("One dead event should be delivered.", 1, events.size());
	assertEquals("The dead event should wrap the original event.",
	EVENT, events.get(0).getEvent());
	}

	public void testDeadEventPosting() {
	GhostCatcher catcher = new GhostCatcher();
	bus.register(catcher);

	bus.post(new DeadEvent(this, EVENT));

	List<DeadEvent> events = catcher.getEvents();
	assertEquals("The explicit DeadEvent should be delivered.",
	1, events.size());
	assertEquals("The dead event must not be re-wrapped.",
	EVENT, events.get(0).getEvent());
	}

	public void testFlattenHierarchy() {
	HierarchyFixture fixture = new HierarchyFixture();
	Set<Class<?>> hierarchy = bus.flattenHierarchy(fixture.getClass());

	assertEquals(5, hierarchy.size());
	assertContains(Object.class, hierarchy);
	assertContains(HierarchyFixtureInterface.class, hierarchy);
	assertContains(HierarchyFixtureSubinterface.class, hierarchy);
	assertContains(HierarchyFixtureParent.class, hierarchy);
	assertContains(HierarchyFixture.class, hierarchy);
	}

	public void testMissingSubscribe() {
	bus.register(new Object());
	}

	public void testUnregister() {
	StringCatcher catcher1 = new StringCatcher();
	StringCatcher catcher2 = new StringCatcher();
	try {
	bus.unregister(catcher1);
	fail("Attempting to unregister an unregistered object succeeded");
	} catch (IllegalArgumentException expected) {
	// OK.
	}

	bus.register(catcher1);
	bus.post(EVENT);
	bus.register(catcher2);
	bus.post(EVENT);

	List<String> expectedEvents = Lists.newArrayList();
	expectedEvents.add(EVENT);
	expectedEvents.add(EVENT);

	assertEquals("Two correct events should be delivered.",
	expectedEvents, catcher1.getEvents());

	assertEquals("One correct event should be delivered.",
	Lists.newArrayList(EVENT), catcher2.getEvents());

	bus.unregister(catcher1);
	bus.post(EVENT);

	assertEquals("Shouldn't catch any more events when unregistered.",
	expectedEvents, catcher1.getEvents());
	assertEquals("Two correct events should be delivered.",
	expectedEvents, catcher2.getEvents());

	try {
	bus.unregister(catcher1);
	fail("Attempting to unregister an unregistered object succeeded");
	} catch (IllegalArgumentException expected) {
	// OK.
	}

	bus.unregister(catcher2);
	bus.post(EVENT);
	assertEquals("Shouldn't catch any more events when unregistered.",
	expectedEvents, catcher1.getEvents());
	assertEquals("Shouldn't catch any more events when unregistered.",
	expectedEvents, catcher2.getEvents());
	}

	// NOTE: This test will always pass if register() is thread-safe but may also
	// pass if it isn't, though this is unlikely.

	public void testRegisterThreadSafety() throws Exception {
	List<StringCatcher> catchers = Lists.newCopyOnWriteArrayList();
	List<Future<?>> futures = Lists.newArrayList();
	ExecutorService executor = Executors.newFixedThreadPool(10);
	int numberOfCatchers = 10000;
	for (int i = 0; i < numberOfCatchers; i++) {
	futures.add(executor.submit(new Registrator(bus, catchers)));
	}
	for (int i = 0; i < numberOfCatchers; i++) {
	futures.get(i).get();
	}
	assertEquals("Unexpected number of catchers in the list",
	numberOfCatchers, catchers.size());
	bus.post(EVENT);
	List<String> expectedEvents = ImmutableList.of(EVENT);
	for (StringCatcher catcher : catchers) {
	assertEquals("One of the registered catchers did not receive an event.",
	expectedEvents, catcher.getEvents());
	}
	}

	private <T> void assertContains(T element, Collection<T> collection) {
	assertTrue("Collection must contain " + element,
	collection.contains(element));
	}

	/**
	* Records a thrown exception information.
	*/
	private static final class RecordingSubscriberExceptionHandler
	implements SubscriberExceptionHandler {

	public SubscriberExceptionContext context;
	public Throwable exception;

	@Override
	public void handleException(Throwable exception,
	SubscriberExceptionContext context) {
	this.exception = exception;
	this.context = context;

	}
	}

	/**
	* Runnable which registers a StringCatcher on an event bus and adds it to a
	* list.
	*/
	private static class Registrator implements Runnable {
	private final EventBus bus;
	private final List<StringCatcher> catchers;

	Registrator(EventBus bus, List<StringCatcher> catchers) {
	this.bus = bus;
	this.catchers = catchers;
	}

	@Override
	public void run() {
	StringCatcher catcher = new StringCatcher();
	bus.register(catcher);
	catchers.add(catcher);
	}
	}

	/**
	* A collector for DeadEvents.
	*
	* @author cbiffle
	*
	*/
	public static class GhostCatcher {
	private List<DeadEvent> events = Lists.newArrayList();

	@Subscribe
	public void ohNoesIHaveDied(DeadEvent event) {
	events.add(event);
	}

	public List<DeadEvent> getEvents() {
	return events;
	}
	}

	public interface HierarchyFixtureInterface {
	// Exists only for hierarchy mapping; no members.
	}

	public interface HierarchyFixtureSubinterface
	extends HierarchyFixtureInterface {
	// Exists only for hierarchy mapping; no members.
	}

	public static class HierarchyFixtureParent
	implements HierarchyFixtureSubinterface {
	// Exists only for hierarchy mapping; no members.
	}

	public static class HierarchyFixture extends HierarchyFixtureParent {
	// Exists only for hierarchy mapping; no members.
	}

	}