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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} and
 * {@code DragSourceDropEvent}.
 * <p>
 * {@code DragSourceEvent}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} 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}. The <i>initiator</i>
 * {@code GraphicsConfiguration} is the {@code GraphicsConfiguration}
 * of the {@code Component} 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}, the reported coordinates are
 * clipped to fit within the bounds of that {@code GraphicsConfiguration}.
 * <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} 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}
     * given a specified {@code DragSourceContext}.
     * The coordinates for this {@code DragSourceEvent}
     * are not specified, so {@code getLocation} will return
     * {@code null} for this event.
     *
     * @param dsc the {@code DragSourceContext}
     *
     * @throws IllegalArgumentException if {@code dsc} is {@code null}.
     *
     * @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} given a specified
     * {@code DragSourceContext}, and coordinates of the cursor
     * location.
     *
     * @param dsc the {@code DragSourceContext}
     * @param x   the horizontal coordinate for the cursor location
     * @param y   the vertical coordinate for the cursor location
     *
     * @throws IllegalArgumentException if {@code dsc} is {@code null}.
     *
     * @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} that
     * originated the event.
     *
     * @return the {@code DragSourceContext} 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} indicating the cursor
     * location in screen coordinates at the moment this event occurred, or
     * {@code null} if the cursor location is not specified for this
     * event.
     *
     * @return the {@code Point} indicating the cursor location
     *         or {@code null} 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;
    }
}