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java.awt.dnd
abstract public class: DragGestureRecognizer [javadoc | source]
java.lang.Object
   java.awt.dnd.DragGestureRecognizer

All Implemented Interfaces:
    java$io$Serializable

Direct Known Subclasses:
    DefaultMouseDragGestureRecognizer, SwingDragGestureRecognizer, MouseDragGestureRecognizer

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 initiating gestures.

The appropriate DragGestureRecognizer subclass instance 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 initiating gesture, it will notify its unicast DragGestureListener by invoking its gestureRecognized() method.

When a concrete DragGestureRecognizer instance detects a drag initiating gesture on the Component it is associated with, it fires a DragGestureEvent to the DragGestureListener registered on its unicast event source for DragGestureListener events. This DragGestureListener is responsible for causing the associated DragSource to start the Drag and Drop operation (if appropriate).

Field Summary
protected  DragSource dragSource    The DragSource associated with this DragGestureRecognizer.
    serial:
 
protected  Component component    The Component associated with this DragGestureRecognizer.
    serial:
 
protected transient  DragGestureListener dragGestureListener    The DragGestureListener associated with this DragGestureRecognizer
protected  int sourceActions    An int representing the type(s) of action(s) used in this Drag and Drop operation.
    serial:
 
protected  ArrayList<InputEvent> events    The list of events (in order) that the DragGestureRecognizer "recognized" as a "gesture" that triggers a drag.
    serial:
 
Constructor:
 protected DragGestureRecognizer(DragSource ds) 
    Construct a new DragGestureRecognizer given the DragSource to be used in this Drag and Drop operation.

    Parameters:
    ds - the DragSource this DragGestureRecognizer will use to process the Drag and Drop operation


    Throws:
    IllegalArgumentException< - /code> if ds is null.
 protected DragGestureRecognizer(DragSource ds,
    Component c) 
    Construct a new DragGestureRecognizer given the DragSource to be used in this Drag and Drop operation, and the Component this DragGestureRecognizer should "observe" for drag initiating gestures.

    Parameters:
    ds - the DragSource this DragGestureRecognizer will use to process the Drag and Drop operation
    c - the Component this DragGestureRecognizer should "observe" the event stream to, in order to detect a drag initiating gesture. If this value is null, the DragGestureRecognizer is not associated with any Component.


    Throws:
    IllegalArgumentException< - /code> if ds is null.
 protected DragGestureRecognizer(DragSource ds,
    Component c,
    int sa) 
    Construct a new DragGestureRecognizer given the DragSource to be used in this Drag and Drop operation, the Component this DragGestureRecognizer should "observe" for drag initiating gestures, and the action(s) supported for this Drag and Drop operation.

    Parameters:
    ds - the DragSource this DragGestureRecognizer will use to process the Drag and Drop operation
    c - the Component this DragGestureRecognizer should "observe" the event stream to, in order to detect a drag initiating gesture. If this value is null, the DragGestureRecognizer is not associated with any Component.
    sa - the set (logical OR) of the DnDConstants that this Drag and Drop operation will support


    Throws:
    IllegalArgumentException< - /code> if ds is null.
 protected DragGestureRecognizer(DragSource ds,
    Component c,
    int sa,
    DragGestureListener dgl) 
    Construct a new DragGestureRecognizer given the DragSource to be used in this Drag and Drop operation, the Component this DragGestureRecognizer should "observe" for drag initiating gestures, the action(s) supported for this Drag and Drop operation, and the DragGestureListener to notify once a drag initiating gesture has been detected.

    Parameters:
    ds - the DragSource this DragGestureRecognizer will use to process the Drag and Drop operation
    c - the Component this DragGestureRecognizer should "observe" the event stream to, in order to detect a drag initiating gesture. If this value is null, the DragGestureRecognizer is not associated with any Component.
    sa - the set (logical OR) of the DnDConstants that this Drag and Drop operation will support
    dgl - the DragGestureRecognizer to notify when a drag gesture is detected


    Throws:
    IllegalArgumentException< - /code> if ds is null.
Method from java.awt.dnd.DragGestureRecognizer Summary:
addDragGestureListener,   appendEvent,   fireDragGestureRecognized,   getComponent,   getDragSource,   getSourceActions,   getTriggerEvent,   registerListeners,   removeDragGestureListener,   resetRecognizer,   setComponent,   setSourceActions,   unregisterListeners
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from java.awt.dnd.DragGestureRecognizer Detail:
 public synchronized  void addDragGestureListener(DragGestureListener dgl) throws TooManyListenersException 
    Register a new DragGestureListener.

 protected synchronized  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 method is used by a DragGestureRecognizer implementation to add an InputEvent subclass (that it believes is one in a series of events that comprise a Drag and Drop operation) to the array of events that this DragGestureRecognizer maintains internally.

 protected synchronized  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.

 public synchronized Component getComponent() 
    This method returns the Component that is to be "observed" by the DragGestureRecognizer for drag initiating gestures.

 public DragSource getDragSource() 
    This method returns the DragSource this DragGestureRecognizer will use in order to process the Drag and Drop operation.

 public synchronized int getSourceActions() 
    This method returns an int representing the type of action(s) this Drag and Drop operation will support.

 public InputEvent getTriggerEvent() 
    This method returns the first event in the series of events that initiated the Drag and Drop operation.

 abstract protected  void registerListeners()
    register this DragGestureRecognizer's Listeners with the Component subclasses must override this method
 public synchronized  void removeDragGestureListener(DragGestureListener dgl) 
    unregister the current DragGestureListener

 public  void resetRecognizer() 
    Reset the Recognizer, if its currently recognizing a gesture, ignore it.
 public synchronized  void setComponent(Component c) 
    set the Component that the DragGestureRecognizer is associated with registerListeners() and unregisterListeners() are called as a side effect as appropriate.

 public synchronized  void setSourceActions(int actions) 
    This method sets the permitted source drag action(s) for this Drag and Drop operation.

 abstract protected  void unregisterListeners()
    unregister this DragGestureRecognizer's Listeners with the Component subclasses must override this method