net.sf.mmm.util.event.base

Class AbstractEventBus

java.lang.Object

net.sf.mmm.util.component.base.AbstractComponent

net.sf.mmm.util.component.base.AbstractLoggableComponent

net.sf.mmm.util.event.base.AbstractEventBus

All Implemented Interfaces:

EventBus

Direct Known Subclasses:

EventBusImpl

public abstract class AbstractEventBus
extends AbstractLoggableComponent
implements EventBus

This is the default implementation of EventBus. It is compatible to work in limited environments such as GWT.

Since:

5.0.0

Author:

Joerg Hohwiller (hohwille at users.sourceforge.net)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	AbstractEventBus.EventDispatcher<E> A dispatcher for all EventListeners of a particular event type.
protected static class	AbstractEventBus.EventListenerContainer<E> A simple container for a registered EventListener.

Field Summary

Fields

Modifier and Type	Field and Description
private Queue<Object>	eventQueue
private Map<Class<?>,AbstractEventBus.EventDispatcher>	eventType2dispatcherMap
private GlobalExceptionHandler	globalExceptionHandler
private CollectionFactory<?>	queueFactory

Constructor Summary

Constructors

Constructor and Description
AbstractEventBus() The constructor.
AbstractEventBus(QueueFactory queueFactory, MapFactory<?> mapFactory) The constructor.

Method Summary

Modifier and Type	Method and Description
<E> void	addListener(Class<E> eventType, EventListener<E> listener) This method registers a listener that is interested in Events.
protected <E> void	dispatchEvent(E event, Collection<Throwable> errors) Dispatches the given Event.
protected void	dispatchEvents() Dispatches all events in the event queue.
private AbstractEventBus.EventDispatcher	getEventDispatcher(Class<?> eventType, boolean createIfNotExists) Gets or creates the AbstractEventBus.EventDispatcher for the given eventType.
protected <E> AbstractEventBus.EventDispatcher<? super E>	getEventDispatcherOptional(Class<E> eventType) Gets the most specific AbstractEventBus.EventDispatcher responsible the given eventType.
protected <E> AbstractEventBus.EventDispatcher<E>	getEventDispatcherRequired(Class<E> eventType) Gets or creates the AbstractEventBus.EventDispatcher for the given eventType.
GlobalExceptionHandler	getGlobalExceptionHandler()
protected void	handleErrors(Collection<Throwable> errors, Object event) This method is called if errors occurred while dispatching events.
protected void	handleUndispatchedEvent(Object event) Called if an Event was send but not dispatched to any registered listener.
boolean	removeListener(EventListener<?> listener) This method removes a listener.
<E> void	sendEvent(E event) This method sends an event to all registered listeners.
void	setGlobalExceptionHandler(GlobalExceptionHandler errorHandler)
protected abstract void	triggerDispatchEvents() Called from sendEvent(Object) to ensure dispatchEvents() is triggered.

Methods inherited from class net.sf.mmm.util.component.base.AbstractLoggableComponent

createLogger, doInitialize, getLogger

Methods inherited from class net.sf.mmm.util.component.base.AbstractComponent

doInitialized, getInitializationState, initialize

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

queueFactory

private final CollectionFactory<?> queueFactory

eventType2dispatcherMap

private final Map<Class<?>,AbstractEventBus.EventDispatcher> eventType2dispatcherMap

eventQueue

private final Queue<Object> eventQueue

globalExceptionHandler

private GlobalExceptionHandler globalExceptionHandler

Constructor Detail

AbstractEventBus

public AbstractEventBus()

The constructor.

AbstractEventBus

public AbstractEventBus(QueueFactory queueFactory,
                        MapFactory<?> mapFactory)

The constructor.

Parameters:

queueFactory - is the factory used to create simple Queues for Event s and EventListeners.

mapFactory - is the factory used to create Maps.

Method Detail

getGlobalExceptionHandler

public GlobalExceptionHandler getGlobalExceptionHandler()

Returns:

the GlobalExceptionHandler instance.

setGlobalExceptionHandler

@Inject
public void setGlobalExceptionHandler(GlobalExceptionHandler errorHandler)

Parameters:

errorHandler - is the GlobalExceptionHandler to Inject.

sendEvent

public <E> void sendEvent(E event)

Description copied from interface: EventBus

This method sends an event to all registered listeners.

Specified by:

sendEvent in interface EventBus

Type Parameters:

E - is the generic type of the Event to send. May be any Object such as a String. However in most cases it is recommended to create real Event classes.

Parameters:

event - is the event to send. May be any Object such as a String. However in most cases it is recommended to create real Event classes.

triggerDispatchEvents

protected abstract void triggerDispatchEvents()

Called from sendEvent(Object) to ensure dispatchEvents() is triggered. This can be done synchronous or asynchronous.

dispatchEvents

protected void dispatchEvents()

Dispatches all events in the event queue.

dispatchEvent

protected <E> void dispatchEvent(E event,
                                 Collection<Throwable> errors)

Dispatches the given Event.

Type Parameters:

E - is the generic type of event.

Parameters:

event - is the Event to dispatch.

errors - is a Collection where errors are collected.

handleUndispatchedEvent

protected void handleUndispatchedEvent(Object event)

Called if an Event was send but not dispatched to any registered listener.

Parameters:

event - is the un-dispatched event.

handleErrors

protected void handleErrors(Collection<Throwable> errors,
                            Object event)

This method is called if errors occurred while dispatching events.

Parameters:

errors - is the Collection with the errors. Will NOT be empty.

event - is the event that has been send and caused the errors.

getEventDispatcherRequired

protected <E> AbstractEventBus.EventDispatcher<E> getEventDispatcherRequired(Class<E> eventType)

Gets or creates the AbstractEventBus.EventDispatcher for the given eventType.

Type Parameters:

E - is the generic type of eventType.

Parameters:

eventType - is the Class reflecting the event.

Returns:

the AbstractEventBus.EventDispatcher responsible for the given eventType.

getEventDispatcherOptional

protected <E> AbstractEventBus.EventDispatcher<? super E> getEventDispatcherOptional(Class<E> eventType)

Gets the most specific AbstractEventBus.EventDispatcher responsible the given eventType.

Type Parameters:

E - is the generic type of eventType.

Parameters:

eventType - is the Class reflecting the event.

Returns:

the most specific AbstractEventBus.EventDispatcher responsible for the given eventType. May be null if no EventListener is registered for a compatible eventType.

getEventDispatcher

private AbstractEventBus.EventDispatcher getEventDispatcher(Class<?> eventType,
                                                            boolean createIfNotExists)

Gets or creates the AbstractEventBus.EventDispatcher for the given eventType.

Parameters:

eventType - is the Class reflecting the event.

createIfNotExists - - if true the requested AbstractEventBus.EventDispatcher will be created if it does not exists, if false this method will return null if it does not exist.

Returns:

the AbstractEventBus.EventDispatcher responsible for the given eventType. May be null if createIfNotExists is null and not available.

addListener

public <E> void addListener(Class<E> eventType,
                            EventListener<E> listener)

Description copied from interface: EventBus

This method registers a listener that is interested in Events.

Specified by:

addListener in interface EventBus

Type Parameters:

E - is the generic type of the Events to listen to. May be any Object such as a String. However in most cases it is recommended to create real Event classes.

Parameters:

eventType - is the type of the Events to listen to (including all derived types). In limited environments such as GWT, interfaces might not be supported.

listener - is the listener to add.

removeListener

public boolean removeListener(EventListener<?> listener)

Description copied from interface: EventBus

This method removes a listener. If the listener was not registered before this method will have no effect.

Specified by:

removeListener in interface EventBus

Parameters:

listener - is the listener to remove.

Returns:

true if the given listener has successfully been removed, false if the listener was NOT registered.