001/* DefaultCellEditor.java --
002   Copyright (C) 2002, 2004, 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 javax.swing;
040
041import java.awt.Component;
042import java.awt.event.ActionEvent;
043import java.awt.event.ActionListener;
044import java.awt.event.ItemEvent;
045import java.awt.event.ItemListener;
046import java.awt.event.MouseEvent;
047import java.io.Serializable;
048import java.util.EventObject;
049
050import javax.swing.JTable;
051import javax.swing.JTextField;
052import javax.swing.event.CellEditorListener;
053import javax.swing.table.TableCellEditor;
054import javax.swing.tree.TreeCellEditor;
055
056/**
057 * The default implementation of {@link TableCellEditor} and
058 * {@link TreeCellEditor}. It provides editor components for
059 * some standard object types.
060 * 
061 * @author Andrew Selkirk
062 * @author Audrius Meskauskas
063 */
064public class DefaultCellEditor
065  extends AbstractCellEditor
066  implements TableCellEditor, TreeCellEditor
067{
068  private static final long serialVersionUID = 3564035141373880027L;
069
070  /**
071   * This changeable module access the editor component in the component
072   * specific way. For instance, to set the value for JTextField, we need to 
073   * call setText(String), and for JCheckBox we need to call 
074   * setSelected(boolean). Each default editor has the component specific
075   * derivative of this class. These derivatives are private inner classes of
076   * the DefaultCellEditor.
077   * 
078   * The editor delegate is also set for the editor component as the action
079   * listener. It listens for the events that indicate that editing has stopped.
080   */
081  protected class EditorDelegate
082    implements ActionListener, ItemListener, Serializable
083  {
084    /**
085     * Use the serial version UID for interoperability.
086     */
087    private static final long serialVersionUID = -1420007406015481933L;
088
089    /**
090     * The object value (updated when getting and setting the value).
091     */
092    protected Object value;
093
094    /**
095     * Constructor EditorDelegate
096     */
097    protected EditorDelegate()
098    {
099      // Nothing to do here.
100    }
101    
102    /**
103     * Set the value for the editor component. This method is normally
104     * overridden to set the value in the way, specific for the text
105     * component, check box or combo box.
106     *
107     * @param aValue the value to set (String, Boolean or Number).
108     */
109    public void setValue(Object aValue)
110    {
111      value = aValue;
112    }
113
114    /**
115     * Get the value for the editor component. This method is normally
116     * overridden to obtain the value in the way, specific for the text
117     * component, check box or combo box.
118     *
119     * @return value the value of the component (String, Boolean or Number).
120     */
121    public Object getCellEditorValue()
122    {
123      return value;
124    } 
125
126    /**
127     * The default method returns true for the {@link MouseEvent} and false 
128     * for any other events.
129     * 
130     * @param event the event to check
131     *
132     * @return true if the passed event is the mouse event and false otherwise.
133     */
134    public boolean isCellEditable(EventObject event)
135    {
136      if (event == null || !(event instanceof MouseEvent) ||
137          (((MouseEvent) event).getClickCount() >= getClickCountToStart()))
138        return true;
139      return false;
140    } // isCellEditable()
141
142    /**
143     * Returns true to indicate that the editing cell can be selected.
144     * 
145     * The default method returns true without action but may be overridden
146     * in derived classes for more specific behavior.
147     * 
148     * @param event unused in default method
149     *
150     * @return true always
151     */
152    public boolean shouldSelectCell(EventObject event)
153    {
154      // return true to indicate that the editing cell may be selected
155      return true;
156    }
157
158    /**
159     * Finish the cell editing session. This method notifies the registered
160     * cell editor listeners (including the table) that the editing has been
161     * stopped. 
162     * 
163     * @return boolean
164     */
165    public boolean stopCellEditing()
166    {
167      fireEditingStopped();
168      return true;
169    } // stopCellEditing()
170
171    /**
172     * Cancel the cell editing session. This method notifies the registered
173     * cell editor listeners (including the table) that the editing has been
174     * canceled.
175     */
176    public void cancelCellEditing()
177    {
178      fireEditingCanceled();
179    } // cancelCellEditing()
180
181    /**
182     * Start editing session and returns true to indicate the editing has begun.
183     * The default method returns true without action but may be overridden
184     * in derived classes for more specific behavior.
185     * 
186     * @param event  the event.
187     * 
188     * @return true, always
189     */
190    public boolean startCellEditing(EventObject event)
191    {
192      // return true to indicate that editing has begun
193      return true;
194    } // startCellEditing()
195
196    /**
197     * This event is fired by the editor component (for instance, by pressing
198     * ENTER in the {@link JTextField}. The default method delegates call to
199     * the {@link #stopCellEditing}, finishing the editing session. 
200     * 
201     * @param event unused in default method
202     */
203    public void actionPerformed(ActionEvent event)
204    {
205      stopCellEditing();
206    } // actionPerformed()
207
208    /**
209     * This event is fired by the editor component.The default method delegates
210     * call to the {@link #stopCellEditing}, finishing the editing session. 
211     * 
212     * @param event unused in default method
213     */
214    public void itemStateChanged(ItemEvent event)
215    {
216      stopCellEditing();
217    } // itemStateChanged()
218
219    /**
220     * Notify the registered listeners (including the table) that the editing
221     * has been completed.
222     */
223    void fireEditingStopped()
224    {
225      CellEditorListener[] listeners = getCellEditorListeners();
226      for (int index = 0; index < listeners.length; index++)
227        listeners[index].editingStopped(changeEvent);
228      
229    }
230    
231    /**
232     * Notify the registered listeners (including the table) that the editing
233     * has been canceled.
234     */
235    void fireEditingCanceled()
236    {
237      CellEditorListener[] listeners = getCellEditorListeners();
238      for (int index = 0; index < listeners.length; index++)
239        listeners[index].editingCanceled(changeEvent);
240    }
241  } // EditorDelegate
242  
243  /**
244   * Provides getter and setter methods to work with the text component.
245   * 
246   * @author Audrius Meskauskas (audriusa@Bioinformatics.org)
247   */
248  private class JTextFieldDelegate extends EditorDelegate
249  {
250    /**
251     * Use the serial version UID for interoperability.
252     */
253    private static final long serialVersionUID = 1;
254    
255    /**
256     * Set the value for the editor component.
257     *
258     * @param aValue the value to set (toString() will be called).
259     */
260    public void setValue(Object aValue)
261    {
262      value = aValue;
263      JTextField f = (JTextField) editorComponent;
264      if (value == null)
265        f.setText("");
266      else
267        f.setText(value.toString());
268    }
269
270    /**
271     * Get the value for the editor component. 
272     *
273     * @return value the value of the component (String)
274     */
275    public Object getCellEditorValue()
276    {
277      JTextField f = (JTextField) editorComponent;
278      return value = f.getText();      
279    }     
280  }
281
282  /**
283   * Provides getter and setter methods to work with the combo box.
284   * 
285   * @author Audrius Meskauskas (audriusa@Bioinformatics.org) 
286   */
287  private class JComboBoxDelegate extends EditorDelegate
288  {
289    /**
290     * Use the serial version UID for interoperability.
291     */
292    private static final long serialVersionUID = 1;
293    
294    /**
295     * Set the value for the editor component.
296     *
297     * @param aValue the value to set.
298     */
299    public void setValue(Object aValue)
300    {
301      value = aValue;      
302      JComboBox c = (JComboBox) editorComponent;
303      if (value != null)
304        c.setSelectedItem(value);
305    }
306
307    /**
308     * Get the value for the editor component. 
309     *
310     * @return value the value of the component (as String)
311     */
312    public Object getCellEditorValue()
313    {
314      JComboBox c = (JComboBox) editorComponent;
315      return value = c.getSelectedItem();
316    } 
317    
318    /**
319     * Returns true to indicate that the editing cell can be selected. If the
320     * check box is not editable, expands it. If it is editable, brings
321     * focus to the editor field.
322     * 
323     * @param event unused in default method
324     *
325     * @return true always
326     */
327    public boolean shouldSelectCell(EventObject event)
328    {
329      JComboBox c = (JComboBox) editorComponent;
330      if (!c.isEditable)
331        c.showPopup();
332      return true;
333    }    
334  }
335
336  /**
337   * Provides getter and setter methods to work with the check box.
338   * 
339   * @author Audrius Meskauskas (audriusa@Bioinformatics.org) 
340   */
341  private class JCheckBoxDelegate extends EditorDelegate
342  {
343    /**
344     * Use the serial version UID for interoperability.
345     */
346    private static final long serialVersionUID = 1;
347    
348    /**
349     * Set the value for the editor component.
350     *
351     * @param value the value to set (must be Boolean).
352     */
353    public void setValue(Object value)
354    {
355      JCheckBox c = (JCheckBox) editorComponent;
356      
357      if (value == null)
358        c.setSelected(false);
359      else
360        c.setSelected( ((Boolean) value).booleanValue());
361    }
362
363    /**
364     * Get the value for the editor component. 
365     *
366     * @return value the value of the component (must be CharSequence)
367     */
368    public Object getCellEditorValue()
369    {
370      JCheckBox c = (JCheckBox) editorComponent;
371      value = c.isSelected() ? Boolean.TRUE : Boolean.FALSE;
372      return value;
373    }     
374  }
375  
376  /**
377   * The Swing JComponent, performing the editing session.
378   */
379  protected JComponent editorComponent;
380
381  /**
382   * The editor delegate, responsible for listening the {@link #editorComponent}
383   * events and getting/setting its value.
384   */
385  protected EditorDelegate delegate;
386
387  /**
388   * The number of the mouse clicks, required to start the editing session.
389   */
390  protected int clickCountToStart;
391
392  /**
393   * Create the DefaultCellEditor that uses the text field as its editor
394   * component (appropriate for the text content)
395   * 
396   * @param textfield the text field as will be used as the editor component
397   */
398  public DefaultCellEditor(JTextField textfield)
399  {
400    editorComponent = textfield;
401    clickCountToStart = 2;
402    delegate = new JTextFieldDelegate();
403    textfield.addActionListener(delegate);
404  } // DefaultCellEditor()
405
406  /**
407   * Constructor DefaultCellEditor that uses the checkbox (appropriate
408   * for boolean values)
409   * 
410   * @param checkbox the checkbox that will be used with this editor.
411   */
412  public DefaultCellEditor(JCheckBox checkbox)
413  {
414    editorComponent = checkbox;
415    clickCountToStart = 1;
416    delegate = new JCheckBoxDelegate();
417    checkbox.addActionListener(delegate);
418  } // DefaultCellEditor()
419
420  /**
421   * Constructor DefaultCellEditor that uses the combo box.
422   * 
423   * @param combobox the combo box that will be used with this editor.
424   */
425  public DefaultCellEditor(JComboBox combobox)
426  {
427    editorComponent = combobox;
428    clickCountToStart = 1;
429    delegate = new JComboBoxDelegate();
430    combobox.addActionListener(delegate);
431  } // DefaultCellEditor()
432
433  /**
434   * Get the component that performs the editing sessions. It is the same 
435   * component that was passed in constructor.
436   * 
437   * @return the component, performing the editing sessions. 
438   */
439  public Component getComponent()
440  {
441    return editorComponent; 
442  } // getComponent()
443
444  /**
445   * Get the number of mouse clicks, required to start the editing session.
446   * 
447   * @return int the number of mouse clicks, required to start the session
448   */
449  public int getClickCountToStart()
450  {
451    return clickCountToStart;
452  } // getClickCountToStart()
453
454  /**
455   * Set the number of mouse clicks, required to start the editing session.
456   * 
457   * @param count the number of clicks, required to start the session
458   */
459  public void setClickCountToStart(int count)
460  {
461    clickCountToStart = count;
462  } // setClickCountToStart()
463
464  /**
465   * Get the value, currently being displayed by the editor component. The 
466   * call is forwarded to the {@link #delegate}.
467   * 
468   * @return Object the value (class depends on the editor component)
469   */
470  public Object getCellEditorValue()
471  {
472    return delegate.getCellEditorValue();
473  } // getCellEditorValue()
474
475  /**
476   * Forwards call to the {@link #delegate}.
477   * 
478   * @param event forwarded to the delegate.
479   *
480   * @return boolean returned by delegate
481   */
482  public boolean isCellEditable(EventObject event)
483  {
484    return delegate.isCellEditable(event);
485  } // isCellEditable()
486
487  /**
488   * Forwards call to the {@link #delegate}.
489   * 
490   * @param event forwarded to the delegate.
491   *
492   * @return boolean returned by delegate
493   */
494  public boolean shouldSelectCell(EventObject event)
495  {
496    return delegate.shouldSelectCell(event);
497  } // shouldSelectCell()
498
499  /**
500   * Forwards call to the {@link #delegate}.
501   * 
502   * @return boolean returned by delegate
503   */
504  public boolean stopCellEditing()
505  {
506    return delegate.stopCellEditing();
507  } // stopCellEditing()
508
509  /**
510   * Forwards call to the {@link #delegate}.
511   */
512  public void cancelCellEditing()
513  {
514    delegate.cancelCellEditing();
515  } // cancelCellEditing()
516
517  /**
518   * Sets an initial value for the editor. 
519   * This will cause the editor to stopEditing and lose any partially 
520   * edited value if the editor is editing when this method is called.
521   * Returns the component that should be added to the client's Component 
522   * hierarchy. Once installed in the client's hierarchy this component will 
523   * then be able to draw and receive user input. 
524   * 
525   * @param tree - the JTree that is asking the editor to edit; this 
526   * parameter can be null
527   * @param value - the value of the cell to be edited
528   * @param isSelected - true is the cell is to be renderer with selection
529   * highlighting
530   * @param expanded - true if the node is expanded
531   * @param leaf - true if the node is a leaf node
532   * @param row - the row index of the node being edited
533   *
534   * @return Component the component for editing
535   */
536  public Component getTreeCellEditorComponent(JTree tree, Object value,
537                                              boolean isSelected,
538                                              boolean expanded, boolean leaf,
539                                              int row)
540  {
541    delegate.setValue(value);
542    return editorComponent;
543  } // getTreeCellEditorComponent()
544
545  /**
546   * Get the cell editor component that will perform the editing session. If
547   * returned once, the same component is also returned on the repetetive calls
548   * again (reused).
549   * 
550   * @param table the table where the editing is performed
551   * @param value the current value of the table. It is set as the initial 
552   *        component value.
553   * @param isSelected if true, the cell is currently selected
554   * @param row the row of the cell being edited
555   * @param column the column of the cell being edited
556   * 
557   * @return Component the component that will perform the editing session
558   */
559  public Component getTableCellEditorComponent(JTable table, Object value,
560                                               boolean isSelected, int row,
561                                               int column)
562  {
563    // NOTE: as specified by Sun, we don't call new() everytime, we return 
564    // editorComponent on each call to getTableCellEditorComponent or
565    // getTreeCellEditorComponent.
566    delegate.setValue(value);
567    return editorComponent;
568  } // getTableCellEditorComponent()
569
570}