org.apache.batik.dom.events

Class EventSupport

public class EventSupport extends Object

The class allows registration and removal of EventListeners on an NodeEventTarget and dispatch of events to that NodeEventTarget.

See Also: NodeEventTarget

Field Summary
protected HashTablebubblingListeners
The bubbling listeners table.
protected HashTablecapturingListeners
The capturing listeners table.
protected AbstractNodenode
The node for which events are being handled.
Constructor Summary
EventSupport(AbstractNode n)
Creates a new EventSupport object.
Method Summary
voidaddEventListener(String type, EventListener listener, boolean useCapture)
This method allows the registration of event listeners on the event target.
voidaddEventListenerNS(String namespaceURI, String type, EventListener listener, boolean useCapture, Object group)
Registers an event listener for the given namespaced event type in the specified group.
protected EventExceptioncreateEventException(short code, String key, Object[] args)
Creates an EventException.
booleandispatchEvent(NodeEventTarget target, Event evt)
This method allows the dispatch of events into the implementations event model.
protected voidfireEventListeners(NodeEventTarget node, AbstractEvent e, EventListenerList.Entry[] listeners, HashSet stoppedGroups, HashSet toBeStoppedGroups)
Fires the given listeners on the given event target.
protected voidfireEventListeners(NodeEventTarget node, AbstractEvent e, boolean useCapture, HashSet stoppedGroups, HashSet toBeStoppedGroups)
Fires the registered listeners on the given event target.
protected NodeEventTarget[]getAncestors(NodeEventTarget node)
Returns all ancestors of the specified node.
EventListenerListgetEventListeners(String type, boolean useCapture)
Returns a list event listeners depending on the specified event type and phase.
static EventgetUltimateOriginalEvent(Event evt)
Returns the ultimate original event for the given event.
booleanhasEventListenerNS(String namespaceURI, String type)
Returns whether this node target has an event listener for the given event namespace URI and type.
voidmoveEventListeners(EventSupport other)
Moves all of the event listeners from this EventSupport object to the given EventSupport object.
protected voidpreventDefault(AbstractEvent e, boolean b)
Calls {@link AbstractEvent#preventDefault(boolean)}.
voidremoveEventListener(String type, EventListener listener, boolean useCapture)
This method allows the removal of event listeners from the event target.
voidremoveEventListenerNS(String namespaceURI, String type, EventListener listener, boolean useCapture)
Deregisters an event listener.
protected voidsetCurrentTarget(AbstractEvent e, NodeEventTarget target)
Calls {@link AbstractEvent#setCurrentTarget}.
protected voidsetEventPhase(AbstractEvent e, short phase)
Calls {@link AbstractEvent#setEventPhase}.
protected voidsetTarget(AbstractEvent e, NodeEventTarget target)
Calls {@link AbstractEvent#setTarget}.
protected voidstopImmediatePropagation(AbstractEvent e, boolean b)
Calls {@link AbstractEvent#stopImmediatePropagation(boolean)}.
protected voidstopPropagation(AbstractEvent e, boolean b)
Calls {@link AbstractEvent#stopPropagation(boolean)}.

Field Detail

bubblingListeners

protected HashTable bubblingListeners
The bubbling listeners table.

capturingListeners

protected HashTable capturingListeners
The capturing listeners table.

node

protected AbstractNode node
The node for which events are being handled.

Constructor Detail

EventSupport

public EventSupport(AbstractNode n)
Creates a new EventSupport object.

Parameters: n the node for which events are being handled

Method Detail

addEventListener

public void addEventListener(String type, EventListener listener, boolean useCapture)
This method allows the registration of event listeners on the event target. If an EventListener is added to an EventTarget which is currently processing an event the new listener will not be triggered by the current event.
If multiple identical EventListeners are registered on the same EventTarget with the same parameters the duplicate instances are discarded. They do not cause the EventListener to be called twice and since they are discarded they do not need to be removed with the removeEventListener method.

Parameters: type The event type for which the user is registering listener The listener parameter takes an interface implemented by the user which contains the methods to be called when the event occurs. useCapture If true, useCapture indicates that the user wishes to initiate capture. After initiating capture, all events of the specified type will be dispatched to the registered EventListener before being dispatched to any EventTargets beneath them in the tree. Events which are bubbling upward through the tree will not trigger an EventListener designated to use capture.

addEventListenerNS

public void addEventListenerNS(String namespaceURI, String type, EventListener listener, boolean useCapture, Object group)
Registers an event listener for the given namespaced event type in the specified group.

createEventException

protected EventException createEventException(short code, String key, Object[] args)
Creates an EventException. Overrides this method if you need to create your own RangeException subclass.

Parameters: code the exception code key the resource key args arguments to use when formatting the message

dispatchEvent

public boolean dispatchEvent(NodeEventTarget target, Event evt)
This method allows the dispatch of events into the implementations event model. Events dispatched in this manner will have the same capturing and bubbling behavior as events dispatched directly by the implementation. The target of the event is the EventTarget on which dispatchEvent is called.

Parameters: target the target node evt Specifies the event type, behavior, and contextual information to be used in processing the event.

Returns: The return value of dispatchEvent indicates whether any of the listeners which handled the event called preventDefault. If preventDefault was called the value is false, else the value is true.

Throws: EventException UNSPECIFIED_EVENT_TYPE_ERR: Raised if the Event's type was not specified by initializing the event before dispatchEvent was called. Specification of the Event's type as null or an empty string will also trigger this exception.

fireEventListeners

protected void fireEventListeners(NodeEventTarget node, AbstractEvent e, EventListenerList.Entry[] listeners, HashSet stoppedGroups, HashSet toBeStoppedGroups)
Fires the given listeners on the given event target.

fireEventListeners

protected void fireEventListeners(NodeEventTarget node, AbstractEvent e, boolean useCapture, HashSet stoppedGroups, HashSet toBeStoppedGroups)
Fires the registered listeners on the given event target.

getAncestors

protected NodeEventTarget[] getAncestors(NodeEventTarget node)
Returns all ancestors of the specified node.

getEventListeners

public EventListenerList getEventListeners(String type, boolean useCapture)
Returns a list event listeners depending on the specified event type and phase.

Parameters: type the event type useCapture

getUltimateOriginalEvent

public static Event getUltimateOriginalEvent(Event evt)
Returns the ultimate original event for the given event.

hasEventListenerNS

public boolean hasEventListenerNS(String namespaceURI, String type)
Returns whether this node target has an event listener for the given event namespace URI and type.

moveEventListeners

public void moveEventListeners(EventSupport other)
Moves all of the event listeners from this EventSupport object to the given EventSupport object. Used by {@link org.apache.batik.dom.AbstractDocument#renameNode(Node,String,String)}.

preventDefault

protected void preventDefault(AbstractEvent e, boolean b)
Calls {@link AbstractEvent#preventDefault(boolean)}.

removeEventListener

public void removeEventListener(String type, EventListener listener, boolean useCapture)
This method allows the removal of event listeners from the event target. If an EventListener is removed from an EventTarget while it is processing an event, it will complete its current actions but will not be triggered again during any later stages of event flow.
If an EventListener is removed from an EventTarget which is currently processing an event the removed listener will still be triggered by the current event.
Calling removeEventListener with arguments which do not identify any currently registered EventListener on the EventTarget has no effect.

Parameters: type Specifies the event type of the EventListener being removed. listener The EventListener parameter indicates the EventListener to be removed. useCapture Specifies whether the EventListener being removed was registered as a capturing listener or not. If a listener was registered twice, one with capture and one without, each must be removed separately. Removal of a capturing listener does not affect a non-capturing version of the same listener, and vice versa.

removeEventListenerNS

public void removeEventListenerNS(String namespaceURI, String type, EventListener listener, boolean useCapture)
Deregisters an event listener.

setCurrentTarget

protected void setCurrentTarget(AbstractEvent e, NodeEventTarget target)
Calls {@link AbstractEvent#setCurrentTarget}.

setEventPhase

protected void setEventPhase(AbstractEvent e, short phase)
Calls {@link AbstractEvent#setEventPhase}.

setTarget

protected void setTarget(AbstractEvent e, NodeEventTarget target)
Calls {@link AbstractEvent#setTarget}.

stopImmediatePropagation

protected void stopImmediatePropagation(AbstractEvent e, boolean b)
Calls {@link AbstractEvent#stopImmediatePropagation(boolean)}.

stopPropagation

protected void stopPropagation(AbstractEvent e, boolean b)
Calls {@link AbstractEvent#stopPropagation(boolean)}.
Copyright B) 2007 Apache Software Foundation. All Rights Reserved.