001/* DragGestureRecognizer.java --
002   Copyright (C) 2002, 2005, 2006 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package java.awt.dnd;
040
041import java.awt.Component;
042import java.awt.Point;
043import java.awt.event.InputEvent;
044import java.io.IOException;
045import java.io.ObjectInputStream;
046import java.io.ObjectOutputStream;
047import java.io.Serializable;
048import java.util.ArrayList;
049import 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 */
057public 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 ? 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