com.github.leanframeworks.minibus.base.bus

Class AbstractEventBus

java.lang.Object

com.github.leanframeworks.minibus.base.bus.AbstractEventBus

All Implemented Interfaces:

EventBus

Direct Known Subclasses:

SimpleEventBus

public abstract class AbstractEventBus
extends Object
implements EventBus

Abstract implementation of an event bus.

This class implements the addition/removal of the various kinds of handlers and filters.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	AbstractEventBus.SubscriptionEntry<C> Entity gathering all information regarding a subscription.

Field Summary

Fields

Modifier and Type	Field and Description
protected List<ExceptionHandler>	exceptionHandlers Registered unchecked exception handlers.
protected Map<Integer,AbstractEventBus.SubscriptionEntry<?>>	idToSubscription Mapping between subscription IDs and subscriptions.
protected Map<Topic<?>,Collection<AbstractEventBus.SubscriptionEntry<?>>>	topicToSubscription Mapping between subscriptions and topics.
protected List<EventHandler<Object>>	undeliveredEventHandlers Registerd handlers for undelivered events.

Constructor Summary

Constructors

Constructor and Description
AbstractEventBus()

Method Summary

Modifier and Type	Method and Description
void	addExceptionHandler(ExceptionHandler handler) Adds the specified exception handler that will be notified whenever and exception is thrown when an event is being dispatched or processed by an event handler.
void	addUndeliveredEventHandler(EventHandler<Object> handler) Adds the specified event handler that will process events that have not been processed by any event handler registered with EventBus.subscribe(Topic, Channel, EventFilter, EventHandler).
protected Channel	createDefaultChannelForHandler(EventHandler<?> handler) Creates a default, dedicated channel for the specified event handler.
void	dispose() Disposes the event bus by removing all event handlers, undelivered event handlers, stopping the dispatching threads, etc.
protected abstract <C> void	publish(Event<C> event) Publishes the specified event on the event bus.
<C> void	publish(Topic<C> topic, C content) Sends the specified content for the specified topic on the broadcast channel.
<C> void	publish(Topic<C> topic, Channel channel, C content) Sends the specified content for the specified topic on the specified channel.
void	publish(Topic<Void> topic) Sends null for the specified topic on the broadcast channel.
void	removeExceptionHandler(ExceptionHandler handler) Removes the specified exception handler
void	removeUndeliveredEventHandler(EventHandler<Object> handler) Removes the specified undelievered event handler.
<C> int	subscribe(Topic<C> topic, Channel channel, EventFilter<? super C> filter, EventHandler<? super C> handler) Registers a subscriber for the specified topic on the specified channel with the specified filter by adding an event handler.
<C> int	subscribe(Topic<C> topic, Channel channel, EventHandler<? super C> handler) Registers a subscriber for the specified topic on the specified channel by adding an event handler.
<C> int	subscribe(Topic<C> topic, EventFilter<? super C> filter, EventHandler<? super C> handler) Registers a subscriber for the specified topic with the specified filter by adding an event handler.
<C> int	subscribe(Topic<C> topic, EventHandler<? super C> handler) Registers a subscriber for the specified topic by adding an event handler.
void	unsubscribe(int id) Unregisters a subscriber that was previously registered.

Methods inherited from class java.lang.Object

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

Field Detail

exceptionHandlers

protected final List<ExceptionHandler> exceptionHandlers

Registered unchecked exception handlers.

undeliveredEventHandlers

protected final List<EventHandler<Object>> undeliveredEventHandlers

Registerd handlers for undelivered events.

topicToSubscription

protected final Map<Topic<?>,Collection<AbstractEventBus.SubscriptionEntry<?>>> topicToSubscription

Mapping between subscriptions and topics.

This mapping can be used to retrieve the event handlers interested in the topic used for the event being dispatched.

idToSubscription

protected final Map<Integer,AbstractEventBus.SubscriptionEntry<?>> idToSubscription

Mapping between subscription IDs and subscriptions.

This mapping can be used to unsubscribe event handlers.

Constructor Detail

AbstractEventBus

public AbstractEventBus()

Method Detail

addExceptionHandler

public void addExceptionHandler(ExceptionHandler handler)

Description copied from interface: EventBus

Adds the specified exception handler that will be notified whenever and exception is thrown when an event is being dispatched or processed by an event handler.

Specified by:

addExceptionHandler in interface EventBus

Parameters:

handler - Exception handler to be added.

See Also:

EventBus.addExceptionHandler(ExceptionHandler)

removeExceptionHandler

public void removeExceptionHandler(ExceptionHandler handler)

Description copied from interface: EventBus

Removes the specified exception handler

Specified by:

removeExceptionHandler in interface EventBus

Parameters:

handler - Exception handler to be removed.

See Also:

EventBus.removeExceptionHandler(ExceptionHandler)

addUndeliveredEventHandler

public void addUndeliveredEventHandler(EventHandler<Object> handler)

Description copied from interface: EventBus

Adds the specified event handler that will process events that have not been processed by any event handler registered with EventBus.subscribe(Topic, Channel, EventFilter, EventHandler).

Specified by:

addUndeliveredEventHandler in interface EventBus

Parameters:

handler - Undelivered event handler to be added.

See Also:

EventBus.addUndeliveredEventHandler(EventHandler)

removeUndeliveredEventHandler

public void removeUndeliveredEventHandler(EventHandler<Object> handler)

Description copied from interface: EventBus

Removes the specified undelievered event handler.

Specified by:

removeUndeliveredEventHandler in interface EventBus

Parameters:

handler - Undelivered event handler to be removed.

See Also:

EventBus.removeUndeliveredEventHandler(EventHandler)

createDefaultChannelForHandler

protected Channel createDefaultChannelForHandler(EventHandler<?> handler)

Creates a default, dedicated channel for the specified event handler.

Parameters:

handler - Event handler to create a dedicated channel for.

Returns:

Dedicated channel.

subscribe

public final <C> int subscribe(Topic<C> topic,
                               EventHandler<? super C> handler)

Registers a subscriber for the specified topic by adding an event handler.

A default, dedicated channel will be used for this event handler.

Type Parameters:

C - Type of content to subscribe for.

Parameters:

topic - Topic to subscribe for.

handler - Event handler that will process the received events.

Returns:

Unique identifier of the subscription that can be used to unsubscribe(int).

See Also:

unsubscribe(int)

subscribe

public final <C> int subscribe(Topic<C> topic,
                               Channel channel,
                               EventHandler<? super C> handler)

Registers a subscriber for the specified topic on the specified channel by adding an event handler.

A default, dedicated channel will be used for this event handler.

Type Parameters:

C - Type of content to subscribe for.

Parameters:

topic - Topic to subscribe for.

channel - Channel on which the events should be received.

handler - Event handler that will process the received events.

Returns:

Unique identifier of the subscription that can be used to unsubscribe(int).

subscribe

public final <C> int subscribe(Topic<C> topic,
                               EventFilter<? super C> filter,
                               EventHandler<? super C> handler)

Registers a subscriber for the specified topic with the specified filter by adding an event handler.

A default, dedicated channel will be used for this event handler.

Type Parameters:

C - Type of content to subscribe for.

Parameters:

topic - Topic to subscribe for.

filter - Additional filter that should be applied before receiving the events.

handler - Event handler that will process the received events.

Returns:

Unique identifier of the subscription that can be used to unsubscribe(int).

subscribe

public final <C> int subscribe(Topic<C> topic,
                               Channel channel,
                               EventFilter<? super C> filter,
                               EventHandler<? super C> handler)

Description copied from interface: EventBus

Registers a subscriber for the specified topic on the specified channel with the specified filter by adding an event handler.

Specified by:

subscribe in interface EventBus

Type Parameters:

C - Type of content to subscribe for.

Parameters:

topic - Topic to subscribe for.

channel - Channel on which the events should be received.

filter - Additional filter that should be applied before receiving the events.

handler - Event handler that will process the received events.

Returns:

Unique identifier of the subscription that can be used to EventBus.unsubscribe(int).

See Also:

EventBus.subscribe(Topic, Channel, EventFilter, EventHandler)

unsubscribe

public void unsubscribe(int id)

Description copied from interface: EventBus

Unregisters a subscriber that was previously registered.

Specified by:

unsubscribe in interface EventBus

Parameters:

id - Identifier of a previous subscription.

See Also:

EventBus.unsubscribe(int)

publish

public final void publish(Topic<Void> topic)

Sends null for the specified topic on the broadcast channel.

The content will be wrapped in an Event that will be dispatched to the registered event handlers.

Parameters:

topic - Topic for which the content must be dispatched.

See Also:

publish(Topic, Channel, Object), publish(Event)

publish

public final <C> void publish(Topic<C> topic,
                              C content)

Sends the specified content for the specified topic on the broadcast channel.

The content will be wrapped in an Event that will be dispatched to the registered event handlers.

Type Parameters:

C - Type of content to be dispatched.

Parameters:

topic - Topic for which the content must be dispatched.

content - Content to be dispatched.

See Also:

publish(Topic, Channel, Object), publish(Event)

publish

public final <C> void publish(Topic<C> topic,
                              Channel channel,
                              C content)

Description copied from interface: EventBus

Sends the specified content for the specified topic on the specified channel.

The content will be wrapped in an Event that will be dispatched to the registered event handlers.

Specified by:

publish in interface EventBus

Type Parameters:

C - Type of content to be dispatched.

Parameters:

topic - Topic for which the content must be dispatched.

channel - Channel on which the event must be dispatched.

content - Content to be dispatched.

See Also:

EventBus.publish(Topic, Channel, Object), publish(Event)

publish

protected abstract <C> void publish(Event<C> event)

Publishes the specified event on the event bus.

This method is called from the other publish methods.

Type Parameters:

C - Type of event content.

Parameters:

event - Event to be dispatched.

dispose

public void dispose()

Description copied from interface: EventBus

Disposes the event bus by removing all event handlers, undelivered event handlers, stopping the dispatching threads, etc.

After calling this method, the event bus may no longer be used, depending on the implementation.

Specified by:

dispose in interface EventBus

See Also:

EventBus.dispose()