001/* Clipboard.java -- Class for transferring data via cut and paste.
002   Copyright (C) 1999, 2001, 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.datatransfer;
040
041import java.io.IOException;
042import java.util.ArrayList;
043
044/**
045 * This class allows data to be transferred using a cut and paste type
046 * mechanism.
047 *
048 * @author Aaron M. Renn (arenn@urbanophile.com)
049 * @author Mark J. Wielaard (mark@klomp.org)
050 */
051public class Clipboard
052{
053  /**
054   * The data currently on this clipboard.  For use by
055   * subclasses. Also returned by the public method getContents().
056   */
057  protected Transferable contents;
058
059  /**
060   * The owner of this clipboard.
061   */
062  protected ClipboardOwner owner;
063
064  // The clipboard name
065  private final String name;
066
067  // The flavor listeners (most likely small).
068  private final ArrayList listeners = new ArrayList(3);
069
070  /**
071   * Initializes a new instance of <code>Clipboard</code> with the
072   * specified name.
073   *
074   * @param name The clipboard name.
075   */
076  public Clipboard(String name)
077  {
078    this.name = name;
079  }
080
081  /**
082    * Returns the name of the clipboard.
083    */
084  public String getName()
085  {
086    return name;
087  }
088
089  /**
090   * Returns the contents of the clipboard.
091   *
092   * @param requestor The object requesting the contents. This
093   * implementation ignores this parameter.
094   *
095   * @exception IllegalStateException If the clipboard is currently unavailable
096   */
097  public synchronized Transferable getContents(Object requestor)
098  {
099    return contents;
100  }
101
102  /**
103   * Sets the content and owner of this clipboard.  If the given owner
104   * is different from the current owner then <code>lostOwnership()</code>
105   * is called on the current owner with the old contents of the given
106   * clipboard.
107   *
108   * @param contents The new clipboard contents.
109   * @param owner The new clipboard owner
110   *
111   * @exception IllegalStateException If the clipboard is currently unavailable
112   */
113  public synchronized void setContents(Transferable contents,
114                                       ClipboardOwner owner)
115  {
116    Transferable oldContents = getContents(null);
117    this.contents = contents;
118    if (this.owner != owner)
119      {
120        ClipboardOwner oldOwner = this.owner;
121        this.owner = owner;
122        if (oldOwner != null)
123          oldOwner.lostOwnership(this, oldContents);
124      }
125
126    FlavorListener[] fs = getFlavorListeners();
127    if (fs.length > 0)
128      {
129        // We are a bit optimistic here. We assume DataFlavors will be
130        // given in the same order. If the number of flavors is
131        // different or the order of the DataFlavors in the list then
132        // fire a change event.
133        boolean newFlavors = ((contents != null && oldContents == null)
134                              || (contents == null && oldContents != null));
135        if (!newFlavors && contents != null && oldContents != null)
136          {
137            DataFlavor[] df1 = contents.getTransferDataFlavors();
138            DataFlavor[] df2 = oldContents.getTransferDataFlavors();
139            newFlavors = df1.length != df2.length;
140            
141            for (int i = 0; !newFlavors && i < df1.length; i++)
142              newFlavors = !df1[i].equals(df2[i]);
143          }
144
145        if (newFlavors)
146          {
147            FlavorEvent e = new FlavorEvent(this);
148            for (int i = 0; i < fs.length; i++)
149              fs[i].flavorsChanged(e);
150          }
151      }
152  }
153
154  public DataFlavor[] getAvailableDataFlavors()
155  {
156    Transferable c = getContents(null);
157    if (c == null)
158      return new DataFlavor[0];
159    else
160      return c.getTransferDataFlavors();
161  }
162
163  public boolean isDataFlavorAvailable(DataFlavor flavor)
164  {
165    DataFlavor[] fs = getAvailableDataFlavors();
166    for (int i = 0; i < fs.length; i++)
167      if (flavor.equals(fs[i]))
168        return true;
169
170    return false;
171  }
172
173  public Object getData(DataFlavor flavor)
174    throws UnsupportedFlavorException, IOException
175  {
176    Transferable c = getContents(null);
177    if (c == null)
178      throw new UnsupportedFlavorException(flavor);
179    else
180      return c.getTransferData(flavor);
181  }
182
183  public void addFlavorListener(FlavorListener listener)
184  {
185    if (listener == null)
186      return;
187
188    synchronized(listeners)
189      {
190        listeners.add(listener);
191      }
192  }
193
194  public void removeFlavorListener(FlavorListener listener)
195  {
196    if (listener == null)
197      return;
198
199    synchronized(listeners)
200      {
201        listeners.remove(listener);
202      }
203  }
204
205  public FlavorListener[] getFlavorListeners()
206  {
207    synchronized(listeners)
208      {
209        return (FlavorListener[])
210          listeners.toArray(new FlavorListener[listeners.size()]);
211      }
212  }
213}