diva.canvas.event
Class EventLayer

java.lang.Object
  diva.canvas.CanvasLayer
      diva.canvas.event.EventLayer

All Implemented Interfaces:

CanvasComponent, EventAcceptor

public class EventLayer
extends CanvasLayer
implements EventAcceptor

An event layer is a canvas layer that accepts mouse events. It is designed to be layered over or under other layers, such as FigureLayer, and accepts a number of options that control whether it consumes events and so on. Event layers can have event listeners attached to them, which will be notified when events occur.

Sample uses of the event layer

• On top of a figure layer, events consumed: trap all events before they get to the figure layer.
• On top of a figure layer, events not consumed: monitor all events but still allow the figure layer to respond.
• Behind of a figure layer: catch events on the "background" of the pane, which didn't hit a figure in the figure layer.

Version:

$Id: EventLayer.java 53042 2009-04-10 20:31:21Z cxh $

Author:

John Reekie

Field Summary

private boolean	_consuming The consuming flag.
private Interactor	_currentInteractor The current interactor
private boolean	_enabled The enabled flag.
private java.util.ArrayList<Interactor>	_interactors The list of attached interactors
private LayerListener	layerListener The layer listeners
private LayerMotionListener	layerMotionListener The layer motion listeners

Constructor Summary

EventLayer()

Method Summary

void	addInteractor(Interactor i) Add an interactor to this interactor.
void	addLayerListener(LayerListener l) Add the given layer listener to this dispatcher.
void	addLayerMotionListener(LayerMotionListener l) Add the given layer motion listener to this dispatcher.
void	dispatchEvent(java.awt.AWTEvent event) Dispatch an AWT event on this layer.
java.util.Iterator	interactors() Return an interactor over the attached interactors.
boolean	isConsuming() Test the consuming flag of this layer.
boolean	isEnabled() Test the enabled flag of this layer.
protected void	processLayerEvent(LayerEvent event) Process a layer event.
void	removeInteractor(Interactor i) Remove the given interactor from this interactor.
void	removeLayerListener(LayerListener l) Remove the given layer listener from this dispatcher.
void	removeLayerMotionListener(LayerMotionListener l) Remove the given layer motion listener from this dispatcher.
void	setConsuming(boolean flag) Set the consuming flag of this layer.
void	setEnabled(boolean flag) Set the enabled flag of this layer.

Methods inherited from class diva.canvas.CanvasLayer

getCanvasPane, getLayerBounds, getParent, getToolTipText, getTransformContext, repaint, repaint, setParent

Methods inherited from class java.lang.Object

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

Methods inherited from interface diva.canvas.CanvasComponent

getParent, getTransformContext, repaint, repaint

Field Detail

_enabled

private boolean _enabled

The enabled flag.

_consuming

private boolean _consuming

The consuming flag.

_currentInteractor

private Interactor _currentInteractor

The current interactor

_interactors

private java.util.ArrayList<Interactor> _interactors

The list of attached interactors

layerListener

private transient LayerListener layerListener

The layer listeners

layerMotionListener

private transient LayerMotionListener layerMotionListener

The layer motion listeners

Constructor Detail

EventLayer

public EventLayer()

Method Detail

addInteractor

public void addInteractor(Interactor i)

Add an interactor to this interactor. The added interactor will have events forwarded to it if it accepts the event.

addLayerListener

public void addLayerListener(LayerListener l)

Add the given layer listener to this dispatcher.

addLayerMotionListener

public void addLayerMotionListener(LayerMotionListener l)

Add the given layer motion listener to this dispatcher.

dispatchEvent

public void dispatchEvent(java.awt.AWTEvent event)

Dispatch an AWT event on this layer. Currently only layer events are handled.

Specified by:

dispatchEvent in interface EventAcceptor

interactors

public java.util.Iterator interactors()

Return an interactor over the attached interactors.

isConsuming

public boolean isConsuming()

Test the consuming flag of this layer. If this flag is set, the layer consumes all input events.

isEnabled

public boolean isEnabled()

Test the enabled flag of this layer. Note that this flag does not indicate whether the layer is actually enabled, as its pane or one if its ancestors may not be enabled.

Specified by:

isEnabled in interface EventAcceptor

processLayerEvent

protected void processLayerEvent(LayerEvent event)

Process a layer event. This method dispatches the event to any registered layer listeners or layer motion listeners, and then to any interactors. If the "consuming" flag is set, it consumes the event before returning.

removeInteractor

public void removeInteractor(Interactor i)

Remove the given interactor from this interactor.

removeLayerListener

public void removeLayerListener(LayerListener l)

Remove the given layer listener from this dispatcher.

removeLayerMotionListener

public void removeLayerMotionListener(LayerMotionListener l)

Remove the given layer motion listener from this dispatcher.

setConsuming

public void setConsuming(boolean flag)

Set the consuming flag of this layer. If this flag is set, the layer consumes all input events.

setEnabled

public void setEnabled(boolean flag)

Set the enabled flag of this layer. If the flag is false, then the layer will not respond to user input events.

Specified by:

setEnabled in interface EventAcceptor