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package java.awt.dnd;

import java.awt.Point;

import java.util.EventObject;


This class is the base class for
DragSourceDragEvent and
DragSourceDropEvent.


DragSourceEvents are generated whenever the drag enters, moves
over, or exits a drop site, when the drop action changes, and when the drag
ends. The location for the generated DragSourceEvent specifies
the mouse cursor location in screen coordinates at the moment this event
occurred.


In a multi-screen environment without a virtual device, the cursor location is
specified in the coordinate system of the initiator
GraphicsConfiguration. The initiator
GraphicsConfiguration is the GraphicsConfiguration
of the Component on which the drag gesture for the current drag
operation was recognized. If the cursor location is outside the bounds of
the initiator GraphicsConfiguration, the reported coordinates are
clipped to fit within the bounds of that GraphicsConfiguration.


In a multi-screen environment with a virtual device, the location is specified
in the corresponding virtual coordinate system. If the cursor location is
outside the bounds of the virtual device the reported coordinates are
clipped to fit within the bounds of the virtual device.

Since:1.2
/**
 * This class is the base class for
 * <code>DragSourceDragEvent</code> and
 * <code>DragSourceDropEvent</code>.
 * <p>
 * <code>DragSourceEvent</code>s are generated whenever the drag enters, moves
 * over, or exits a drop site, when the drop action changes, and when the drag
 * ends. The location for the generated <code>DragSourceEvent</code> specifies
 * the mouse cursor location in screen coordinates at the moment this event
 * occurred.
 * <p>
 * In a multi-screen environment without a virtual device, the cursor location is
 * specified in the coordinate system of the <i>initiator</i>
 * <code>GraphicsConfiguration</code>. The <i>initiator</i>
 * <code>GraphicsConfiguration</code> is the <code>GraphicsConfiguration</code>
 * of the <code>Component</code> on which the drag gesture for the current drag
 * operation was recognized. If the cursor location is outside the bounds of
 * the initiator <code>GraphicsConfiguration</code>, the reported coordinates are
 * clipped to fit within the bounds of that <code>GraphicsConfiguration</code>.
 * <p>
 * In a multi-screen environment with a virtual device, the location is specified
 * in the corresponding virtual coordinate system. If the cursor location is
 * outside the bounds of the virtual device the reported coordinates are
 * clipped to fit within the bounds of the virtual device.
 *
 * @since 1.2
 */

public class DragSourceEvent extends EventObject {

    private static final long serialVersionUID = -763287114604032641L;

    
The boolean indicating whether the cursor location
is specified for this event.

@serial
/**
     * The <code>boolean</code> indicating whether the cursor location
     * is specified for this event.
     *
     * @serial
     */
    private final boolean locationSpecified;

    
The horizontal coordinate for the cursor location at the moment this
event occurred if the cursor location is specified for this event;
otherwise zero.

@serial
/**
     * The horizontal coordinate for the cursor location at the moment this
     * event occurred if the cursor location is specified for this event;
     * otherwise zero.
     *
     * @serial
     */
    private final int x;

    
The vertical coordinate for the cursor location at the moment this event
occurred if the cursor location is specified for this event;
otherwise zero.

@serial
/**
     * The vertical coordinate for the cursor location at the moment this event
     * occurred if the cursor location is specified for this event;
     * otherwise zero.
     *
     * @serial
     */
    private final int y;

    
Construct a DragSourceEvent
given a specified DragSourceContext.
The coordinates for this DragSourceEvent
are not specified, so getLocation will return
null for this event.

Params:
  • dsc – the DragSourceContext
Throws:
See Also:
/**
     * Construct a <code>DragSourceEvent</code>
     * given a specified <code>DragSourceContext</code>.
     * The coordinates for this <code>DragSourceEvent</code>
     * are not specified, so <code>getLocation</code> will return
     * <code>null</code> for this event.
     *
     * @param dsc the <code>DragSourceContext</code>
     *
     * @throws IllegalArgumentException if <code>dsc</code> is <code>null</code>.
     *
     * @see #getLocation
     */

    public DragSourceEvent(DragSourceContext dsc) {
        super(dsc);
        locationSpecified = false;
        this.x = 0;
        this.y = 0;
    }

    
Construct a DragSourceEvent given a specified
DragSourceContext, and coordinates of the cursor
location.

Params:
  • dsc – the DragSourceContext
  • x –   the horizontal coordinate for the cursor location
  • y –   the vertical coordinate for the cursor location
Throws:
Since:1.4
/**
     * Construct a <code>DragSourceEvent</code> given a specified
     * <code>DragSourceContext</code>, and coordinates of the cursor
     * location.
     *
     * @param dsc the <code>DragSourceContext</code>
     * @param x   the horizontal coordinate for the cursor location
     * @param y   the vertical coordinate for the cursor location
     *
     * @throws IllegalArgumentException if <code>dsc</code> is <code>null</code>.
     *
     * @since 1.4
     */
    public DragSourceEvent(DragSourceContext dsc, int x, int y) {
        super(dsc);
        locationSpecified = true;
        this.x = x;
        this.y = y;
    }

    
This method returns the DragSourceContext that
originated the event.



Returns:the DragSourceContext that originated the event
/**
     * This method returns the <code>DragSourceContext</code> that
     * originated the event.
     * <P>
     * @return the <code>DragSourceContext</code> that originated the event
     */

    public DragSourceContext getDragSourceContext() {
        return (DragSourceContext)getSource();
    }

    
This method returns a Point indicating the cursor
location in screen coordinates at the moment this event occurred, or
null if the cursor location is not specified for this
event.

Returns:the Point indicating the cursor location
        or null if the cursor location is not specified
Since:1.4
/**
     * This method returns a <code>Point</code> indicating the cursor
     * location in screen coordinates at the moment this event occurred, or
     * <code>null</code> if the cursor location is not specified for this
     * event.
     *
     * @return the <code>Point</code> indicating the cursor location
     *         or <code>null</code> if the cursor location is not specified
     * @since 1.4
     */
    public Point getLocation() {
        if (locationSpecified) {
            return new Point(x, y);
        } else {
            return null;
        }
    }

    
This method returns the horizontal coordinate of the cursor location in
screen coordinates at the moment this event occurred, or zero if the
cursor location is not specified for this event.

Returns:an integer indicating the horizontal coordinate of the cursor
        location or zero if the cursor location is not specified
Since:1.4
/**
     * This method returns the horizontal coordinate of the cursor location in
     * screen coordinates at the moment this event occurred, or zero if the
     * cursor location is not specified for this event.
     *
     * @return an integer indicating the horizontal coordinate of the cursor
     *         location or zero if the cursor location is not specified
     * @since 1.4
     */
    public int getX() {
        return x;
    }

    
This method returns the vertical coordinate of the cursor location in
screen coordinates at the moment this event occurred, or zero if the
cursor location is not specified for this event.

Returns:an integer indicating the vertical coordinate of the cursor
        location or zero if the cursor location is not specified
Since:1.4
/**
     * This method returns the vertical coordinate of the cursor location in
     * screen coordinates at the moment this event occurred, or zero if the
     * cursor location is not specified for this event.
     *
     * @return an integer indicating the vertical coordinate of the cursor
     *         location or zero if the cursor location is not specified
     * @since 1.4
     */
    public int getY() {
        return y;
    }
}