KeyedComboBoxModel


1   /* ========================================================================
2    * JCommon : a free general purpose class library for the Java(tm) platform
3    * ========================================================================
4    *
5    * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
6    *
7    * Project Info:  http://www.jfree.org/jcommon/index.html
8    *
9    * This library is free software; you can redistribute it and/or modify it
10   * under the terms of the GNU Lesser General Public License as published by
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12   * (at your option) any later version.
13   *
14   * This library is distributed in the hope that it will be useful, but
15   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17   * License for more details.
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24   * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25   * in the United States and other countries.]
26   *
27   * ------------------
28   * KeyedComboBoxModel.java
29   * ------------------
30   * (C) Copyright 2004, by Thomas Morgner and Contributors.
31   *
32   * Original Author:  Thomas Morgner;
33   * Contributor(s):   David Gilbert (for Object Refinery Limited);
34   *
35   * $Id: KeyedComboBoxModel.java,v 1.6 2006/12/03 15:33:33 taqua Exp $
36   *
37   * Changes
38   * -------
39   * 07-Jun-2004 : Added JCommon header (DG);
40   *
41   */
42  package org.jfree.ui;
43  
44  import java.util.ArrayList  ;
45  import javax.swing.ComboBoxModel  ;
46  import javax.swing.event.ListDataEvent  ;
47  import javax.swing.event.ListDataListener  ;
48  
49  /**
50   * The KeyedComboBox model allows to define an internal key (the data element)
51   * for every entry in the model.
52   * <p/>
53   * This class is usefull in all cases, where the public text differs from the
54   * internal view on the data. A separation between presentation data and
55   * processing data is a prequesite for localizing combobox entries. This model
56   * does not allow selected elements, which are not in the list of valid
57   * elements.
58   *
59   * @author Thomas Morgner
60   */
61  public class KeyedComboBoxModel implements ComboBoxModel  
62  {
63  
64    /**
65     * The internal data carrier to map keys to values and vice versa.
66     */
67    private static class ComboBoxItemPair
68    {
69      /**
70       * The key.
71       */
72      private Object   key;
73      /**
74       * The value for the key.
75       */
76      private Object   value;
77  
78      /**
79       * Creates a new item pair for the given key and value. The value can be
80       * changed later, if needed.
81       *
82       * @param key   the key
83       * @param value the value
84       */
85      public ComboBoxItemPair(final Object   key, final Object   value)
86      {
87        this.key = key;
88        this.value = value;
89      }
90  
91      /**
92       * Returns the key.
93       *
94       * @return the key.
95       */
96      public Object   getKey()
97      {
98        return key;
99      }
100 
101     /**
102      * Returns the value.
103      *
104      * @return the value for this key.
105      */
106     public Object   getValue()
107     {
108       return value;
109     }
110 
111     /**
112      * Redefines the value stored for that key.
113      *
114      * @param value the new value.
115      */
116     public void setValue(final Object   value)
117     {
118       this.value = value;
119     }
120   }
121 
122   /**
123    * The index of the selected item.
124    */
125   private int selectedItemIndex;
126   private Object   selectedItemValue;
127   /**
128    * The data (contains ComboBoxItemPairs).
129    */
130   private ArrayList   data;
131   /**
132    * The listeners.
133    */
134   private ArrayList   listdatalistener;
135   /**
136    * The cached listeners as array.
137    */
138   private transient ListDataListener  [] tempListeners;
139   private boolean allowOtherValue;
140 
141   /**
142    * Creates a new keyed combobox model.
143    */
144   public KeyedComboBoxModel()
145   {
146     data = new ArrayList  ();
147     listdatalistener = new ArrayList  ();
148   }
149 
150   /**
151    * Creates a new keyed combobox model for the given keys and values. Keys
152    * and values must have the same number of items.
153    *
154    * @param keys   the keys
155    * @param values the values
156    */
157   public KeyedComboBoxModel(final Object  [] keys, final Object  [] values)
158   {
159     this();
160     setData(keys, values);
161   }
162 
163   /**
164    * Replaces the data in this combobox model. The number of keys must be
165    * equals to the number of values.
166    *
167    * @param keys   the keys
168    * @param values the values
169    */
170   public void setData(final Object  [] keys, final Object  [] values)
171   {
172     if (values.length != keys.length)
173     {
174       throw new IllegalArgumentException  ("Values and text must have the same length.");
175     }
176 
177     data.clear();
178     data.ensureCapacity(keys.length);
179 
180     for (int i = 0; i < values.length; i++)
181     {
182       add(keys[i], values[i]);
183     }
184 
185     selectedItemIndex = -1;
186     final ListDataEvent   evt = new ListDataEvent  
187         (this, ListDataEvent.CONTENTS_CHANGED, 0, data.size() - 1);
188     fireListDataEvent(evt);
189   }
190 
191   /**
192    * Notifies all registered list data listener of the given event.
193    *
194    * @param evt the event.
195    */
196   protected synchronized void fireListDataEvent(final ListDataEvent   evt)
197   {
198     if (tempListeners == null)
199     {
200       tempListeners = (ListDataListener  []) listdatalistener.toArray
201           (new ListDataListener  [listdatalistener.size()]);
202     }
203     for (int i = 0; i < tempListeners.length; i++)
204     {
205       final ListDataListener   l = tempListeners[i];
206       l.contentsChanged(evt);
207     }
208   }
209 
210   /**
211    * Returns the selected item.
212    *
213    * @return The selected item or <code>null</code> if there is no selection
214    */
215   public Object   getSelectedItem()
216   {
217     return selectedItemValue;
218   }
219 
220   /**
221    * Defines the selected key. If the object is not in the list of values, no
222    * item gets selected.
223    *
224    * @param anItem the new selected item.
225    */
226   public void setSelectedKey(final Object   anItem)
227   {
228     if (anItem == null)
229     {
230       selectedItemIndex = -1;
231       selectedItemValue = null;
232     }
233     else
234     {
235       final int newSelectedItem = findDataElementIndex(anItem);
236       if (newSelectedItem == -1)
237       {
238         selectedItemIndex = -1;
239         selectedItemValue = null;
240       }
241       else
242       {
243         selectedItemIndex = newSelectedItem;
244         selectedItemValue = getElementAt(selectedItemIndex);
245       }
246     }
247     fireListDataEvent(new ListDataEvent  (this, ListDataEvent.CONTENTS_CHANGED, -1, -1));
248   }
249 
250   /**
251    * Set the selected item. The implementation of this  method should notify
252    * all registered <code>ListDataListener</code>s that the contents have
253    * changed.
254    *
255    * @param anItem the list object to select or <code>null</code> to clear the
256    *               selection
257    */
258   public void setSelectedItem(final Object   anItem)
259   {
260     if (anItem == null)
261     {
262       selectedItemIndex = -1;
263       selectedItemValue = null;
264     }
265     else
266     {
267       final int newSelectedItem = findElementIndex(anItem);
268       if (newSelectedItem == -1)
269       {
270         if (isAllowOtherValue())
271         {
272           selectedItemIndex = -1;
273           selectedItemValue = anItem;
274         }
275         else
276         {
277           selectedItemIndex = -1;
278           selectedItemValue = null;
279         }
280       }
281       else
282       {
283         selectedItemIndex = newSelectedItem;
284         selectedItemValue = getElementAt(selectedItemIndex);
285       }
286     }
287     fireListDataEvent(new ListDataEvent  (this, ListDataEvent.CONTENTS_CHANGED, -1, -1));
288   }
289 
290   private boolean isAllowOtherValue()
291   {
292     return allowOtherValue;
293   }
294 
295   public void setAllowOtherValue(final boolean allowOtherValue)
296   {
297     this.allowOtherValue = allowOtherValue;
298   }
299 
300   /**
301    * Adds a listener to the list that's notified each time a change to the data
302    * model occurs.
303    *
304    * @param l the <code>ListDataListener</code> to be added
305    */
306   public synchronized void addListDataListener(final ListDataListener   l)
307   {
308     listdatalistener.add(l);
309     tempListeners = null;
310   }
311 
312   /**
313    * Returns the value at the specified index.
314    *
315    * @param index the requested index
316    * @return the value at <code>index</code>
317    */
318   public Object   getElementAt(final int index)
319   {
320     if (index >= data.size())
321     {
322       return null;
323     }
324 
325     final ComboBoxItemPair datacon = (ComboBoxItemPair) data.get(index);
326     if (datacon == null)
327     {
328       return null;
329     }
330     return datacon.getValue();
331   }
332 
333   /**
334    * Returns the key from the given index.
335    *
336    * @param index the index of the key.
337    * @return the the key at the specified index.
338    */
339   public Object   getKeyAt(final int index)
340   {
341     if (index >= data.size())
342     {
343       return null;
344     }
345 
346     if (index < 0)
347     {
348       return null;
349     }
350 
351     final ComboBoxItemPair datacon = (ComboBoxItemPair) data.get(index);
352     if (datacon == null)
353     {
354       return null;
355     }
356     return datacon.getKey();
357   }
358 
359   /**
360    * Returns the selected data element or null if none is set.
361    *
362    * @return the selected data element.
363    */
364   public Object   getSelectedKey()
365   {
366     return getKeyAt(selectedItemIndex);
367   }
368 
369   /**
370    * Returns the length of the list.
371    *
372    * @return the length of the list
373    */
374   public int getSize()
375   {
376     return data.size();
377   }
378 
379   /**
380    * Removes a listener from the list that's notified each time a change to
381    * the data model occurs.
382    *
383    * @param l the <code>ListDataListener</code> to be removed
384    */
385   public void removeListDataListener(final ListDataListener   l)
386   {
387     listdatalistener.remove(l);
388     tempListeners = null;
389   }
390 
391   /**
392    * Searches an element by its data value. This method is called by the
393    * setSelectedItem method and returns the first occurence of the element.
394    *
395    * @param anItem the item
396    * @return the index of the item or -1 if not found.
397    */
398   private int findDataElementIndex(final Object   anItem)
399   {
400     if (anItem == null)
401     {
402       throw new NullPointerException  ("Item to find must not be null");
403     }
404 
405     for (int i = 0; i < data.size(); i++)
406     {
407       final ComboBoxItemPair datacon = (ComboBoxItemPair) data.get(i);
408       if (anItem.equals(datacon.getKey()))
409       {
410         return i;
411       }
412     }
413     return -1;
414   }
415 
416   /**
417    * Tries to find the index of element with the given key. The key must not
418    * be null.
419    *
420    * @param key the key for the element to be searched.
421    * @return the index of the key, or -1 if not found.
422    */
423   public int findElementIndex(final Object   key)
424   {
425     if (key == null)
426     {
427       throw new NullPointerException  ("Item to find must not be null");
428     }
429 
430     for (int i = 0; i < data.size(); i++)
431     {
432       final ComboBoxItemPair datacon = (ComboBoxItemPair) data.get(i);
433       if (key.equals(datacon.getValue()))
434       {
435         return i;
436       }
437     }
438     return -1;
439   }
440 
441   /**
442    * Removes an entry from the model.
443    *
444    * @param key the key
445    */
446   public void removeDataElement(final Object   key)
447   {
448     final int idx = findDataElementIndex(key);
449     if (idx == -1)
450     {
451       return;
452     }
453 
454     data.remove(idx);
455     final ListDataEvent   evt = new ListDataEvent  
456         (this, ListDataEvent.INTERVAL_REMOVED, idx, idx);
457     fireListDataEvent(evt);
458   }
459 
460   /**
461    * Adds a new entry to the model.
462    *
463    * @param key    the key
464    * @param cbitem the display value.
465    */
466   public void add(final Object   key, final Object   cbitem)
467   {
468     final ComboBoxItemPair con = new ComboBoxItemPair(key, cbitem);
469     data.add(con);
470     final ListDataEvent   evt = new ListDataEvent  
471         (this, ListDataEvent.INTERVAL_ADDED, data.size() - 2, data.size() - 2);
472     fireListDataEvent(evt);
473   }
474 
475   /**
476    * Removes all entries from the model.
477    */
478   public void clear()
479   {
480     final int size = getSize();
481     data.clear();
482     final ListDataEvent   evt = new ListDataEvent  (this, ListDataEvent.INTERVAL_REMOVED, 0, size - 1);
483     fireListDataEvent(evt);
484   }
485 
486 }
487
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