old-autovect-branch/libjava/classpath/java/awt/datatransfer/Clipboard.java

   1 /* Clipboard.java -- Class for transferring data via cut and paste.
   2    Copyright (C) 1999, 2001, 2005 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package java.awt.datatransfer;
  40
  41 import java.io.IOException;
  42 import java.util.ArrayList;
  43
  44 /**
  45  * This class allows data to be transferred using a cut and paste type
  46  * mechanism.
  47  *
  48  * @author Aaron M. Renn (arenn@urbanophile.com)
  49  * @author Mark J. Wielaard (mark@klomp.org)
  50  */
  51 public class Clipboard
  52 {
  53   /**
  54    * The data currently on this clipboard.  For use by
  55    * subclasses. Also returned by the public method getContents().
  56    */
  57   protected Transferable contents;
  58
  59   /**
  60    * The owner of this clipboard.
  61    */
  62   protected ClipboardOwner owner;
  63
  64   // The clipboard name
  65   private final String name;
  66
  67   // The flavor listeners (most likely small).
  68   private final ArrayList listeners = new ArrayList(3);
  69
  70   /**
  71    * Initializes a new instance of <code>Clipboard</code> with the
  72    * specified name.
  73    *
  74    * @param name The clipboard name.
  75    */
  76   public Clipboard(String name)
  77   {
  78     this.name = name;
  79   }
  80
  81   /**
  82     * Returns the name of the clipboard.
  83     */
  84   public String getName()
  85   {
  86     return name;
  87   }
  88
  89   /**
  90    * Returns the contents of the clipboard.
  91    *
  92    * @param requestor The object requesting the contents. This
  93    * implementation ignores this parameter.
  94    *
  95    * @exception IllegalStateException If the clipboard is currently unavailable
  96    */
  97   public synchronized Transferable getContents(Object requestor)
  98   {
  99     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     synchronized(listeners)
 186       {
 187         listeners.add(listener);
 188       }
 189   }
 190
 191   public void removeFlavorListener(FlavorListener listener)
 192   {
 193     synchronized(listeners)
 194       {
 195         listeners.remove(listener);
 196       }
 197   }
 198
 199   public FlavorListener[] getFlavorListeners()
 200   {
 201     synchronized(listeners)
 202       {
 203         return (FlavorListener[])
 204           listeners.toArray(new FlavorListener[listeners.size()]);
 205       }
 206   }
 207 }