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    1   /*
    2    * Copyright (c) 1998, 2003, Oracle and/or its affiliates. All rights reserved.
    3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    4    *
    5    * This code is free software; you can redistribute it and/or modify it
    6    * under the terms of the GNU General Public License version 2 only, as
    7    * published by the Free Software Foundation.  Oracle designates this
    8    * particular file as subject to the "Classpath" exception as provided
    9    * by Oracle in the LICENSE file that accompanied this code.
   10    *
   11    * This code is distributed in the hope that it will be useful, but WITHOUT
   12    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13    * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14    * version 2 for more details (a copy is included in the LICENSE file that
   15    * accompanied this code).
   16    *
   17    * You should have received a copy of the GNU General Public License version
   18    * 2 along with this work; if not, write to the Free Software Foundation,
   19    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20    *
   21    * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   22    * or visit www.oracle.com if you need additional information or have any
   23    * questions.
   24    */
   25   
   26   package java.awt.dnd;
   27   
   28   import java.awt.Component;
   29   
   30   import java.awt.event.MouseEvent;
   31   import java.awt.event.MouseListener;
   32   import java.awt.event.MouseMotionListener;
   33   
   34   /**
   35    * This abstract subclass of <code>DragGestureRecognizer</code>
   36    * defines a <code>DragGestureRecognizer</code>
   37    * for mouse-based gestures.
   38    *
   39    * Each platform implements its own concrete subclass of this class,
   40    * available via the Toolkit.createDragGestureRecognizer() method,
   41    * to encapsulate
   42    * the recognition of the platform dependent mouse gesture(s) that initiate
   43    * a Drag and Drop operation.
   44    * <p>
   45    * Mouse drag gesture recognizers should honor the
   46    * drag gesture motion threshold, available through
   47    * {@link DragSource#getDragThreshold}.
   48    * A drag gesture should be recognized only when the distance
   49    * in either the horizontal or vertical direction between
   50    * the location of the latest mouse dragged event and the
   51    * location of the corresponding mouse button pressed event
   52    * is greater than the drag gesture motion threshold.
   53    * <p>
   54    * Drag gesture recognizers created with
   55    * {@link DragSource#createDefaultDragGestureRecognizer}
   56    * follow this convention.
   57    *
   58    * @author Laurence P. G. Cable
   59    *
   60    * @see java.awt.dnd.DragGestureListener
   61    * @see java.awt.dnd.DragGestureEvent
   62    * @see java.awt.dnd.DragSource
   63    */
   64   
   65   public abstract class MouseDragGestureRecognizer extends DragGestureRecognizer implements MouseListener, MouseMotionListener {
   66   
   67       private static final long serialVersionUID = 6220099344182281120L;
   68   
   69       /**
   70        * Construct a new <code>MouseDragGestureRecognizer</code>
   71        * given the <code>DragSource</code> for the
   72        * <code>Component</code> c, the <code>Component</code>
   73        * to observe, the action(s)
   74        * permitted for this drag operation, and
   75        * the <code>DragGestureListener</code> to
   76        * notify when a drag gesture is detected.
   77        * <P>
   78        * @param ds  The DragSource for the Component c
   79        * @param c   The Component to observe
   80        * @param act The actions permitted for this Drag
   81        * @param dgl The DragGestureListener to notify when a gesture is detected
   82        *
   83        */
   84   
   85       protected MouseDragGestureRecognizer(DragSource ds, Component c, int act, DragGestureListener dgl) {
   86           super(ds, c, act, dgl);
   87       }
   88   
   89       /**
   90        * Construct a new <code>MouseDragGestureRecognizer</code>
   91        * given the <code>DragSource</code> for
   92        * the <code>Component</code> c,
   93        * the <code>Component</code> to observe, and the action(s)
   94        * permitted for this drag operation.
   95        * <P>
   96        * @param ds  The DragSource for the Component c
   97        * @param c   The Component to observe
   98        * @param act The actions permitted for this drag
   99        */
  100   
  101       protected MouseDragGestureRecognizer(DragSource ds, Component c, int act) {
  102           this(ds, c, act, null);
  103       }
  104   
  105       /**
  106        * Construct a new <code>MouseDragGestureRecognizer</code>
  107        * given the <code>DragSource</code> for the
  108        * <code>Component</code> c, and the
  109        * <code>Component</code> to observe.
  110        * <P>
  111        * @param ds  The DragSource for the Component c
  112        * @param c   The Component to observe
  113        */
  114   
  115       protected MouseDragGestureRecognizer(DragSource ds, Component c) {
  116           this(ds, c, DnDConstants.ACTION_NONE);
  117       }
  118   
  119       /**
  120        * Construct a new <code>MouseDragGestureRecognizer</code>
  121        * given the <code>DragSource</code> for the <code>Component</code>.
  122        * <P>
  123        * @param ds  The DragSource for the Component
  124        */
  125   
  126       protected MouseDragGestureRecognizer(DragSource ds) {
  127           this(ds, null);
  128       }
  129   
  130       /**
  131        * register this DragGestureRecognizer's Listeners with the Component
  132        */
  133   
  134       protected void registerListeners() {
  135           component.addMouseListener(this);
  136           component.addMouseMotionListener(this);
  137       }
  138   
  139       /**
  140        * unregister this DragGestureRecognizer's Listeners with the Component
  141        *
  142        * subclasses must override this method
  143        */
  144   
  145   
  146       protected void unregisterListeners() {
  147           component.removeMouseListener(this);
  148           component.removeMouseMotionListener(this);
  149       }
  150   
  151       /**
  152        * Invoked when the mouse has been clicked on a component.
  153        * <P>
  154        * @param e the <code>MouseEvent</code>
  155        */
  156   
  157       public void mouseClicked(MouseEvent e) { }
  158   
  159       /**
  160        * Invoked when a mouse button has been
  161        * pressed on a <code>Component</code>.
  162        * <P>
  163        * @param e the <code>MouseEvent</code>
  164        */
  165   
  166       public void mousePressed(MouseEvent e) { }
  167   
  168       /**
  169        * Invoked when a mouse button has been released on a component.
  170        * <P>
  171        * @param e the <code>MouseEvent</code>
  172        */
  173   
  174       public void mouseReleased(MouseEvent e) { }
  175   
  176       /**
  177        * Invoked when the mouse enters a component.
  178        * <P>
  179        * @param e the <code>MouseEvent</code>
  180        */
  181   
  182       public void mouseEntered(MouseEvent e) { }
  183   
  184       /**
  185        * Invoked when the mouse exits a component.
  186        * <P>
  187        * @param e the <code>MouseEvent</code>
  188        */
  189   
  190       public void mouseExited(MouseEvent e) { }
  191   
  192       /**
  193        * Invoked when a mouse button is pressed on a component.
  194        * <P>
  195        * @param e the <code>MouseEvent</code>
  196        */
  197   
  198       public void mouseDragged(MouseEvent e) { }
  199   
  200       /**
  201        * Invoked when the mouse button has been moved on a component
  202        * (with no buttons no down).
  203        * <P>
  204        * @param e the <code>MouseEvent</code>
  205        */
  206   
  207       public void mouseMoved(MouseEvent e) { }
  208   }

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