001    /* AbstractCellEditor.java --
002       Copyright (C) 2002, 2004, 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 javax.swing;
040    
041    import java.io.Serializable;
042    import java.util.EventObject;
043    
044    import javax.swing.event.CellEditorListener;
045    import javax.swing.event.ChangeEvent;
046    import javax.swing.event.EventListenerList;
047    
048    /**
049     * An abstract superclass for table and tree cell editors. This provides some
050     * common shared functionality.
051     *
052     * @author Andrew Selkirk
053     */
054    public abstract class AbstractCellEditor
055      implements CellEditor, Serializable
056    {
057      private static final long serialVersionUID = -1048006551406220959L;
058    
059      /**
060       * Our Swing event listeners.
061       */
062      protected EventListenerList listenerList;
063    
064      /**
065       * The cached ChangeEvent.
066       */
067      protected transient ChangeEvent changeEvent;
068    
069      /**
070       * Creates a new instance of AbstractCellEditor.
071       */
072      public AbstractCellEditor()
073      {
074        listenerList = new EventListenerList();
075        changeEvent = new ChangeEvent(this);
076      }
077    
078      /**
079       * Returns <code>true</code> if the cell is editable using
080       * <code>event</code>, <code>false</code>
081       * if it's not. The default behaviour is to return <code>true</code>.
082       *
083       * @param event an event
084       *
085       * @return <code>true</code> if the cell is editable using
086       *     <code>event</code>, <code>false</code> if it's not
087       */
088      public boolean isCellEditable(EventObject event)
089      {
090        return true;
091      }
092    
093      /**
094       * Returns <code>true</code> if the editing cell should be selected,
095       * <code>false</code> otherwise. This is usually returning <code>true</code>,
096       * but in some special cases it might be useful not to switch cell selection
097       * when editing one cell.
098       *
099       * @param event an event
100       *
101       * @return <code>true</code> if the editing cell should be selected,
102       *     <code>false</code> otherwise
103       */
104      public boolean shouldSelectCell(EventObject event)
105      {
106        return true;
107      }
108    
109      /**
110       * Stop editing the cell and accept any partial value that has been entered
111       * into the cell.
112       *
113       * @return <code>true</code> if editing has been stopped successfully,
114       *     <code>false</code>otherwise
115       */
116      public boolean stopCellEditing()
117      {
118        fireEditingStopped();
119        return true;
120      }
121    
122      /**
123       * Stop editing the cell and do not accept any partial value that has
124       * been entered into the cell.
125       */
126      public void cancelCellEditing()
127      {
128        fireEditingCanceled();
129      }
130    
131      /**
132       * Adds a CellEditorListener to the list of CellEditorListeners of this
133       * CellEditor.
134       *
135       * @param listener the CellEditorListener to add
136       */
137      public void addCellEditorListener(CellEditorListener listener)
138      {
139        listenerList.add(CellEditorListener.class, listener);
140      }
141    
142      /**
143       * Removes the specified CellEditorListener from the list of the
144       * CellEditorListeners of this CellEditor.
145       *
146       * @param listener the CellEditorListener to remove
147       */
148      public void removeCellEditorListener(CellEditorListener listener)
149      {
150        listenerList.remove(CellEditorListener.class, listener);
151      }
152    
153      /**
154       * Returns the list of CellEditorListeners that have been registered
155       * in this CellEditor.
156       *
157       * @return the list of CellEditorListeners that have been registered
158       *     in this CellEditor
159       *
160       * @since 1.4
161       */
162      public CellEditorListener[] getCellEditorListeners()
163      {
164        return (CellEditorListener[]) listenerList.getListeners(
165            CellEditorListener.class);
166      }
167    
168      /**
169       * Notifies all registered listeners that the editing of the cell has has been
170       * stopped.
171       */
172      protected void fireEditingStopped()
173      {
174        CellEditorListener[] listeners = getCellEditorListeners();
175    
176        for (int index = 0; index < listeners.length; index++)
177          {
178            listeners[index].editingStopped(changeEvent);
179          }
180      }
181    
182      /**
183       * Notifies all registered listeners that the editing of the cell has
184       * has been canceled.
185       */
186      protected void fireEditingCanceled()
187      {
188        CellEditorListener[] listeners = getCellEditorListeners();
189    
190        for (int index = 0; index < listeners.length; index++)
191          {
192            listeners[index].editingCanceled(changeEvent);
193          }
194      }
195    }