java.awt.dnd
Class DragGestureRecognizer

java.lang.Object
  |
  +--java.awt.dnd.DragGestureRecognizer

Direct Known Subclasses:

MouseDragGestureRecognizer

public abstract class DragGestureRecognizer

extends Object

The DragGestureRecognizer is an abstract base class for the specification of a platform-dependent listener that can be associated with a particular Component in order to identify platform-dependent drag and drop action initiating gestures.

The appropriate DragGestureRecognizer subclass is obtained from the DragSource asssociated with a particular Component, or from the Toolkit object via its createDragGestureRecognizer() method.

Once the DragGestureRecognizer is associated with a particular Component it will register the appropriate Listener interfaces on that Component in order to track the input Events delivered to the Component.

Once the DragGestureRecognizer identifies a sequence of Events on the Component as a Drag and Drop action initiating gesture it will notify its unicast DragGestureListener by invoking its gestureRecognized() method.

See Also:

DragGestureListener, DragGestureEvent, DragSource

Field Summary

protected Component	component
protected DragGestureListener	dragGestureListener
protected DragSource	dragSource
protected ArrayList	events
protected int	sourceActions

Constructor Summary

protected	DragGestureRecognizer(DragSource ds) construct a new DragGestureRecognizer
protected	DragGestureRecognizer(DragSource ds, Component c) construct a new DragGestureRecognizer
protected	DragGestureRecognizer(DragSource ds, Component c, int sa) construct a new DragGestureRecognizer
protected	DragGestureRecognizer(DragSource ds, Component c, int sa, DragGestureListener dgl) construct a new DragGestureRecognizer

Method Summary

void	addDragGestureListener(DragGestureListener dgl) register a new DragGestureListener
protected void	appendEvent(InputEvent awtie) Listeners registered on the Component by this Recognizer shall record all Events that are recognized as part of the series of Events that go to comprise a Drag and Drop initiating gesture via this API.
protected void	fireDragGestureRecognized(int dragAction, Point p) notify the DragGestureListener that a Drag and Drop initiating gesture has occurred.
Component	getComponent()
DragSource	getDragSource()
int	getSourceActions()
InputEvent	getTriggerEvent()
protected abstract void	registerListeners() register this DragGestureRecognizer's Listeners with the Component subclasses must override this method
void	removeDragGestureListener(DragGestureListener dgl) unregister the current DragGestureListener
void	resetRecognizer() reset the Recognizer, if its currently recognizing a gesture, ignore it.
void	setComponent(Component c) set the Component that the DragGestureRecognizer is associated with registerListeners() and unregisterListeners() are called as a side effect as appropriate.
void	setSourceActions(int actions) set the permitted source drag actions
protected abstract void	unregisterListeners() unregister this DragGestureRecognizer's Listeners with the Component subclasses must override this method

Methods inherited from class java.lang.Object

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

Field Detail

dragSource

protected DragSource dragSource

component

protected Component component

dragGestureListener

protected DragGestureListener dragGestureListener

sourceActions

protected int sourceActions

events

protected ArrayList events

Constructor Detail

DragGestureRecognizer

protected DragGestureRecognizer(DragSource ds,
                                Component c,
                                int sa,
                                DragGestureListener dgl)

construct a new DragGestureRecognizer

Parameters:

ds - The DragSource for the Component c

c - The Component to observe

sa - The source drag actions

dgl - The DragGestureRecognizer to notify when a gesture is detected

DragGestureRecognizer

protected DragGestureRecognizer(DragSource ds,
                                Component c,
                                int sa)

construct a new DragGestureRecognizer

Parameters:

ds - The DragSource for the Component c

sa - The source drag actions

c - The Component to observe

DragGestureRecognizer

protected DragGestureRecognizer(DragSource ds,
                                Component c)

construct a new DragGestureRecognizer

Parameters:

ds - The DragSource for the Component c

c - The Component to observe

DragGestureRecognizer

protected DragGestureRecognizer(DragSource ds)

construct a new DragGestureRecognizer

Parameters:

ds - The DragSource for the Component c

Method Detail

registerListeners

protected abstract void registerListeners()

register this DragGestureRecognizer's Listeners with the Component subclasses must override this method

unregisterListeners

protected abstract void unregisterListeners()

unregister this DragGestureRecognizer's Listeners with the Component subclasses must override this method

getDragSource

public DragSource getDragSource()

Returns:

the DragSource

getComponent

public Component getComponent()

Returns:

The Component this DragGestureRecognizer is associated with

setComponent

public void setComponent(Component c)

set the Component that the DragGestureRecognizer is associated with registerListeners() and unregisterListeners() are called as a side effect as appropriate.

Parameters:

c - The Component or null

getSourceActions

public int getSourceActions()

Returns:

the currently permitted source actions

setSourceActions

public void setSourceActions(int actions)

set the permitted source drag actions

getTriggerEvent

public InputEvent getTriggerEvent()

Returns:

the initial event that triggered the gesture

resetRecognizer

public void resetRecognizer()

reset the Recognizer, if its currently recognizing a gesture, ignore it.

addDragGestureListener

public void addDragGestureListener(DragGestureListener dgl)
                            throws TooManyListenersException

register a new DragGestureListener

removeDragGestureListener

public void removeDragGestureListener(DragGestureListener dgl)

unregister the current DragGestureListener

fireDragGestureRecognized

protected void fireDragGestureRecognized(int dragAction,
                                         Point p)

notify the DragGestureListener that a Drag and Drop initiating gesture has occurred. Then reset the state of the Recognizer.

Parameters:

dragAction - The action initially selected by the users gesture

p - The point (in Component coords) where the gesture originated

appendEvent

protected void appendEvent(InputEvent awtie)

Listeners registered on the Component by this Recognizer shall record all Events that are recognized as part of the series of Events that go to comprise a Drag and Drop initiating gesture via this API. this state is cleared when a the gesture is completed, after the DragGestureListener is notified.