DragSourceAdapter (Java SE 21 & JDK 21)
Description: declaration: module: java.desktop, package: java.awt.dnd, class: DragSourceAdapter
Keywords: java.awt.dnd.DragSourceAdapter class

Module java.desktop
Package java.awt.dnd

# Class DragSourceAdapter

java.lang.Object
java.awt.dnd.DragSourceAdapter

All Implemented Interfaces:
  `DragSourceListener`, `DragSourceMotionListener`, `EventListener`

public abstract class DragSourceAdapter extends Object implements DragSourceListener, DragSourceMotionListener
An abstract adapter class for receiving drag source events. The methods in this class are empty. This class exists only as a convenience for creating listener objects.

Extend this class to create a `DragSourceEvent` listener and override the methods for the events of interest. (If you implement the `DragSourceListener` interface, you have to define all of the methods in it. This abstract class defines null methods for them all, so you only have to define methods for events you care about.)

Create a listener object using the extended class and then register it with a `DragSource`. When the drag enters, moves over, or exits a drop site, when the drop action changes, and when the drag ends, the relevant method in the listener object is invoked, and the `DragSourceEvent` is passed to it.

The drop site is associated with the previous `dragEnter()` invocation if the latest invocation of `dragEnter()` on this adapter corresponds to that drop site and is not followed by a `dragExit()` invocation on this adapter.

Since:
  1.4
See Also:
  - `DragSourceEvent`
  - `DragSourceListener`
  - `DragSourceMotionListener`

- ## Constructor Summary

  Constructors
  Modifier
  Constructor
  Description
  `protected`
  `DragSourceAdapter()`
  Constructs a `DragSourceAdapter`.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `dragDropEnd(DragSourceDropEvent dsde)`
  This method is invoked to signify that the Drag and Drop operation is complete.
  `void`
  `dragEnter(DragSourceDragEvent dsde)`
  Called as the cursor's hotspot enters a platform-dependent drop site.
  `void`
  `dragExit(DragSourceEvent dse)`
  Called as the cursor's hotspot exits a platform-dependent drop site.
  `void`
  `dragMouseMoved(DragSourceDragEvent dsde)`
  Called whenever the mouse is moved during a drag operation.
  `void`
  `dragOver(DragSourceDragEvent dsde)`
  Called as the cursor's hotspot moves over a platform-dependent drop site.
  `void`
  `dropActionChanged(DragSourceDragEvent dsde)`
  Called when the user has modified the drop gesture.

  ### Methods declared in class java.lang.Object

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

- ## Constructor Details

  - ### DragSourceAdapter

    protected DragSourceAdapter()
    Constructs a `DragSourceAdapter`.

- ## Method Details

  - ### dragEnter

    public void dragEnter(DragSourceDragEvent dsde)
    Called as the cursor's hotspot enters a platform-dependent drop site. This method is invoked when all the following conditions are true:
    - The cursor's hotspot enters the operable part of a platform-dependent drop site.
    - The drop site is active.
    - The drop site accepts the drag.
    Specified by:
      `dragEnter` in interface `DragSourceListener`
    Parameters:
      `dsde` - the `DragSourceDragEvent`

  - ### dragOver

    public void dragOver(DragSourceDragEvent dsde)
    Called as the cursor's hotspot moves over a platform-dependent drop site. This method is invoked when all the following conditions are true:
    - The cursor's hotspot has moved, but still intersects the operable part of the drop site associated with the previous dragEnter() invocation.
    - The drop site is still active.
    - The drop site accepts the drag.
    Specified by:
      `dragOver` in interface `DragSourceListener`
    Parameters:
      `dsde` - the `DragSourceDragEvent`

  - ### dragMouseMoved

    public void dragMouseMoved(DragSourceDragEvent dsde)
    Called whenever the mouse is moved during a drag operation.
    Specified by:
      `dragMouseMoved` in interface `DragSourceMotionListener`
    Parameters:
      `dsde` - the `DragSourceDragEvent`

  - ### dropActionChanged

    public void dropActionChanged(DragSourceDragEvent dsde)
    Called when the user has modified the drop gesture. This method is invoked when the state of the input device(s) that the user is interacting with changes. Such devices are typically the mouse buttons or keyboard modifiers that the user is interacting with.
    Specified by:
      `dropActionChanged` in interface `DragSourceListener`
    Parameters:
      `dsde` - the `DragSourceDragEvent`

  - ### dragExit

    public void dragExit(DragSourceEvent dse)
    Called as the cursor's hotspot exits a platform-dependent drop site. This method is invoked when any of the following conditions are true:
    - The cursor's hotspot no longer intersects the operable part of the drop site associated with the previous dragEnter() invocation.
    OR
    - The drop site associated with the previous dragEnter() invocation is no longer active.
    OR
    - The drop site associated with the previous dragEnter() invocation has rejected the drag.
    Specified by:
      `dragExit` in interface `DragSourceListener`
    Parameters:
      `dse` - the `DragSourceEvent`

  - ### dragDropEnd

    public void dragDropEnd(DragSourceDropEvent dsde)
    This method is invoked to signify that the Drag and Drop operation is complete. The getDropSuccess() method of the `DragSourceDropEvent` can be used to determine the termination state. The getDropAction() method returns the operation that the drop site selected to apply to the Drop operation. Once this method is complete, the current `DragSourceContext` and associated resources become invalid.
    Specified by:
      `dragDropEnd` in interface `DragSourceListener`
    Parameters:
      `dsde` - the `DragSourceDropEvent`