nova.core.event.bus

Class EventBus<T>

java.lang.Object

nova.core.event.bus.EventBus<T>

Type Parameters:

T - event type

Direct Known Subclasses:

CancelableEventBus, GlobalEvents

public class EventBus<T>
extends java.lang.Object

A general purpose event bus. This class is thread-safe and listeners can be added or removed concurrently, no external locking is ever needed.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	EventBus.EventBinder<E extends T>
protected class	EventBus.EventListenerNode
protected static class	EventBus.TypedEventListener<E extends T,T> A wrapper for an event listener that only accepts a specific type of event.

Field Summary

Fields

Modifier and Type	Field and Description
static int	PRIORITY_DEFAULT
static int	PRIORITY_HIGH
static int	PRIORITY_LOW
protected java.util.List<EventBus.EventListenerNode>	unsortedListeners

Constructor Summary

Constructors

Constructor and Description
EventBus()

Method Summary

Modifier and Type	Method and Description
protected void	buildCache() Builds an ordered list cachedListeners.
void	clear()
int	count()
protected java.util.List<EventBus.EventListenerNode>	getSortedListeners() Retrieves the sorted listeners.
protected void	invalidateCache() Invalidates the sorted listeners.
boolean	isEmpty() Checks if there are any listeners in this list.
<E extends T> EventBus.EventBinder<E>	on() Retrieves the EventBinder object to bind an EventListener to ths EventBus that only accepts a specific subclass of <T>
<E extends T> EventBus.EventBinder<E>	on(java.lang.Class<E> clazz)
void	publish(T event) Publishes an event by calling all of the registered listeners.
boolean	remove(EventListener<T> listener) Removes an EventListener from the list.

Methods inherited from class java.lang.Object

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

Field Detail

PRIORITY_HIGH

public static final int PRIORITY_HIGH

See Also:

Constant Field Values

PRIORITY_DEFAULT

public static final int PRIORITY_DEFAULT

See Also:

Constant Field Values

PRIORITY_LOW

public static final int PRIORITY_LOW

See Also:

Constant Field Values

unsortedListeners

protected final java.util.List<EventBus.EventListenerNode> unsortedListeners

Constructor Detail

EventBus

public EventBus()

Method Detail

buildCache

protected void buildCache()

Builds an ordered list cachedListeners. Sorts using topological sort algorithm.

invalidateCache

protected void invalidateCache()

Invalidates the sorted listeners. Call this after tweaking with unsortedListeners.

getSortedListeners

protected java.util.List<EventBus.EventListenerNode> getSortedListeners()

Retrieves the sorted listeners. Calls buildCache() if the listeners aren't sorted.

Returns:

The sorted listeners.

clear

public void clear()

remove

public boolean remove(EventListener<T> listener)

Removes an EventListener from the list.

Parameters:

listener - listener to be removed

Returns:

true if the listener was removed, false it it wasn't there

isEmpty

public boolean isEmpty()

Checks if there are any listeners in this list.

Returns:

true if empty

count

public int count()

publish

public void publish(T event)

Publishes an event by calling all of the registered listeners.

Parameters:

event - event to be published

on

public <E extends T> EventBus.EventBinder<E> on()

Retrieves the EventBinder object to bind an EventListener to ths EventBus that only accepts a specific subclass of <T>

Type Parameters:

E - The event type

Returns:

event listener's handle

on

public <E extends T> EventBus.EventBinder<E> on(java.lang.Class<E> clazz)