001    /* DragGestureRecognizer.java --
002       Copyright (C) 2002, 2005, 2006 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package java.awt.dnd;
040    
041    import java.awt.Component;
042    import java.awt.Point;
043    import java.awt.event.InputEvent;
044    import java.io.IOException;
045    import java.io.ObjectInputStream;
046    import java.io.ObjectOutputStream;
047    import java.io.Serializable;
048    import java.util.ArrayList;
049    import java.util.TooManyListenersException;
050    
051    /**
052     * STUBBED
053     * @author Michael Koch (konqueror@gmx.de)
054     * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
055     * @since 1.2
056     */
057    public abstract class DragGestureRecognizer implements Serializable
058    {
059      /**
060       * Compatible with JDK 1.2+.
061       */
062      private static final long serialVersionUID = 8996673345831063337L;
063    
064      protected DragSource dragSource;
065      protected Component component;
066      protected transient DragGestureListener dragGestureListener;
067      protected int sourceActions;
068      protected ArrayList<InputEvent> events = new ArrayList<InputEvent>();
069    
070      protected DragGestureRecognizer(DragSource ds, Component c, int sa,
071                                      DragGestureListener dgl)
072      {
073        if (ds == null)
074          throw new IllegalArgumentException();
075        dragSource = ds;
076        component = c;
077        sourceActions = sa;
078        dragGestureListener = dgl;
079      }
080    
081      protected DragGestureRecognizer(DragSource ds, Component c, int sa)
082      {
083        this(ds, c, sa, null);
084      }
085    
086      protected DragGestureRecognizer(DragSource ds, Component c)
087      {
088        this(ds, c, 0, null);
089      }
090    
091      protected DragGestureRecognizer(DragSource ds)
092      {
093        this(ds, null, 0, null);
094      }
095    
096      protected abstract void registerListeners();
097    
098      protected abstract void unregisterListeners();
099    
100      public DragSource getDragSource()
101      {
102        return dragSource;
103      }
104    
105      public Component getComponent()
106      {
107        return component;
108      }
109    
110      public void setComponent(Component c)
111      {
112        component = c;
113      }
114    
115      public int getSourceActions()
116      {
117        return sourceActions;
118      }
119    
120      public void setSourceActions(int sa)
121      {
122        sourceActions = sa;
123      }
124    
125      public InputEvent getTriggerEvent()
126      {
127        return events.size() > 0 ? (InputEvent) events.get(0) : null;
128      }
129    
130      /**
131       * Resets the recognizer. If a gesture is currently recognize, discard it.
132       */
133      public void resetRecognizer()
134      {
135        events.clear();
136      }
137    
138      /**
139       * Register a new DragGestureListener.
140       *
141       * @exception TooManyListenersException If a DragGestureListener has already
142       * been added.
143       */
144      public void addDragGestureListener(DragGestureListener dgl)
145        throws TooManyListenersException
146      {
147        if (dragGestureListener != null)
148          throw new TooManyListenersException();
149        dragGestureListener = dgl;
150      }
151    
152      public void removeDragGestureListener(DragGestureListener dgl)
153      {
154        if (dragGestureListener != dgl)
155          throw new IllegalArgumentException();
156        dragGestureListener = null;
157      }
158    
159      /**
160       * Fires a <code>DragGestureEvent</code> to the DragGestureListener
161       * associated with this object, if there is one.
162       */
163      protected void fireDragGestureRecognized(int dragAction, Point p)
164      {
165        if(dragGestureListener != null)
166          dragGestureListener.dragGestureRecognized
167            (new DragGestureEvent(this, dragAction, p, events));
168        resetRecognizer();
169      }
170    
171      protected void appendEvent(InputEvent e)
172      {
173        if (e == null)
174          return;
175        events.add(e);
176      }
177    
178      private void readObject(ObjectInputStream s)
179        throws ClassNotFoundException, IOException
180      {
181        s.defaultReadObject();
182        dragGestureListener = (DragGestureListener) s.readObject();
183      }
184    
185      private void writeObject(ObjectOutputStream s) throws IOException
186      {
187        s.defaultWriteObject();
188        s.writeObject(dragGestureListener instanceof Serializable
189                      ? dragGestureListener : null);
190      }
191    } // class DragGestureRecognizer