Title


1   /* ===========================================================
2    * JFreeChart : a free chart 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/jfreechart/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 
11   * the Free Software Foundation; either version 2.1 of the License, or 
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.
18   *
19   * You should have received a copy of the GNU Lesser General Public
20   * License along with this library; if not, write to the Free Software
21   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
22   * USA.  
23   *
24   * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
25   * in the United States and other countries.]
26   * 
27   * ----------
28   * Title.java
29   * ----------
30   * (C) Copyright 2000-2005, by David Berry and Contributors.
31   *
32   * Original Author:  David Berry;
33   * Contributor(s):   David Gilbert (for Object Refinery Limited);
34   *                   Nicolas Brodu;
35   *
36   * $Id: Title.java,v 1.10.2.1 2005/10/25 20:58:34 mungady Exp $
37   *
38   * Changes (from 21-Aug-2001)
39   * --------------------------
40   * 21-Aug-2001 : Added standard header (DG);
41   * 18-Sep-2001 : Updated header (DG);
42   * 14-Nov-2001 : Package com.jrefinery.common.ui.* changed to 
43   *               com.jrefinery.ui.* (DG);
44   * 07-Feb-2002 : Changed blank space around title from Insets --> Spacer, to 
45   *               allow for relative or absolute spacing (DG);
46   * 25-Jun-2002 : Removed unnecessary imports (DG);
47   * 01-Oct-2002 : Fixed errors reported by Checkstyle (DG);
48   * 14-Oct-2002 : Changed the event listener storage structure (DG);
49   * 11-Sep-2003 : Took care of listeners while cloning (NB);
50   * 22-Sep-2003 : Spacer cannot be null. Added nullpointer checks for this (TM);
51   * 08-Jan-2003 : Renamed AbstractTitle --> Title and moved to separate 
52   *               package (DG);
53   * 26-Oct-2004 : Refactored to implement Block interface, and removed redundant 
54   *               constants (DG);
55   * 11-Jan-2005 : Removed deprecated code in preparation for the 1.0.0 
56   *               release (DG);
57   * 02-Feb-2005 : Changed Spacer --> RectangleInsets for padding (DG);
58   * 03-May-2005 : Fixed problem in equals() method (DG);
59   * 
60   */
61  
62  package org.jfree.chart.title;
63  
64  import java.awt.Graphics2D  ;
65  import java.awt.geom.Rectangle2D  ;
66  import java.io.IOException  ;
67  import java.io.ObjectInputStream  ;
68  import java.io.ObjectOutputStream  ;
69  import java.io.Serializable  ;
70  
71  import javax.swing.event.EventListenerList  ;
72  
73  import org.jfree.chart.block.AbstractBlock;
74  import org.jfree.chart.block.Block;
75  import org.jfree.chart.event.TitleChangeEvent;
76  import org.jfree.chart.event.TitleChangeListener;
77  import org.jfree.ui.HorizontalAlignment;
78  import org.jfree.ui.RectangleEdge;
79  import org.jfree.ui.RectangleInsets;
80  import org.jfree.ui.VerticalAlignment;
81  import org.jfree.util.ObjectUtilities;
82  
83  /**
84   * The base class for all chart titles.  A chart can have multiple titles, 
85   * appearing at the top, bottom, left or right of the chart.
86   * <P>
87   * Concrete implementations of this class will render text and images, and 
88   * hence do the actual work of drawing titles.
89   *
90   * @author David Berry
91   */
92  public abstract class Title extends AbstractBlock 
93                              implements Block, Cloneable  , Serializable   {
94  
95      /** For serialization. */
96      private static final long serialVersionUID = -6675162505277817221L;
97      
98      /** The default title position. */
99      public static final RectangleEdge DEFAULT_POSITION = RectangleEdge.TOP;
100 
101     /** The default horizontal alignment. */
102     public static final HorizontalAlignment 
103         DEFAULT_HORIZONTAL_ALIGNMENT = HorizontalAlignment.CENTER;
104 
105     /** The default vertical alignment. */
106     public static final VerticalAlignment 
107         DEFAULT_VERTICAL_ALIGNMENT = VerticalAlignment.CENTER;
108 
109     /** Default title padding. */
110     public static final RectangleInsets DEFAULT_PADDING = new RectangleInsets(
111         1, 1, 1, 1
112     );
113 
114     /** The title position. */
115     private RectangleEdge position;
116 
117     /** The horizontal alignment of the title content. */
118     private HorizontalAlignment horizontalAlignment;
119 
120     /** The vertical alignment of the title content. */
121     private VerticalAlignment verticalAlignment;
122 
123     /** Storage for registered change listeners. */
124     private transient EventListenerList   listenerList;
125 
126     /** 
127      * A flag that can be used to temporarily disable the listener mechanism. 
128      */
129     private boolean notify;
130 
131     /**
132      * Creates a new title, using default attributes where necessary.
133      */
134     protected Title() {
135         this(
136             Title.DEFAULT_POSITION,
137             Title.DEFAULT_HORIZONTAL_ALIGNMENT,
138             Title.DEFAULT_VERTICAL_ALIGNMENT,
139             Title.DEFAULT_PADDING
140         );
141     }
142 
143     /**
144      * Creates a new title, using default attributes where necessary.
145      *
146      * @param position  the position of the title (<code>null</code> not 
147      *                  permitted).
148      * @param horizontalAlignment  the horizontal alignment of the title 
149      *                             (<code>null</code> not permitted).
150      * @param verticalAlignment  the vertical alignment of the title 
151      *                           (<code>null</code> not permitted).
152      */
153     protected Title(RectangleEdge position, 
154                     HorizontalAlignment horizontalAlignment, 
155                     VerticalAlignment verticalAlignment) {
156 
157         this(
158             position, horizontalAlignment, verticalAlignment,
159             Title.DEFAULT_PADDING
160         );
161 
162     }
163 
164     /**
165      * Creates a new title.
166      *
167      * @param position  the position of the title (<code>null</code> not 
168      *                  permitted).
169      * @param horizontalAlignment  the horizontal alignment of the title (LEFT,
170      *                             CENTER or RIGHT, <code>null</code> not 
171      *                             permitted).
172      * @param verticalAlignment  the vertical alignment of the title (TOP, 
173      *                           MIDDLE or BOTTOM, <code>null</code> not 
174      *                           permitted).
175      * @param padding  the amount of space to leave around the outside of the 
176      *                 title (<code>null</code> not permitted).
177      */
178     protected Title(RectangleEdge position,
179                     HorizontalAlignment horizontalAlignment, 
180                     VerticalAlignment verticalAlignment,
181                     RectangleInsets padding) {
182 
183         // check arguments...
184         if (position == null) {
185             throw new IllegalArgumentException  ("Null 'position' argument.");
186         }
187         if (horizontalAlignment == null) {
188             throw new IllegalArgumentException  (
189                 "Null 'horizontalAlignment' argument."
190             );
191         }
192 
193         if (verticalAlignment == null) {
194             throw new IllegalArgumentException  (
195                 "Null 'verticalAlignment' argument."
196             );
197         }
198         if (padding == null) {
199             throw new IllegalArgumentException  ("Null 'spacer' argument.");
200         }
201 
202         this.position = position;
203         this.horizontalAlignment = horizontalAlignment;
204         this.verticalAlignment = verticalAlignment;
205         setPadding(padding);
206         this.listenerList = new EventListenerList  ();
207         this.notify = true;
208 
209     }
210 
211     /**
212      * Returns the position of the title.
213      *
214      * @return The title position (never <code>null</code>).
215      */
216     public RectangleEdge getPosition() {
217         return this.position;
218     }
219 
220     /**
221      * Sets the position for the title and sends a {@link TitleChangeEvent} to 
222      * all registered listeners.
223      *
224      * @param position  the position (<code>null</code> not permitted).
225      */
226     public void setPosition(RectangleEdge position) {
227         if (position == null) {
228             throw new IllegalArgumentException  ("Null 'position' argument.");
229         }
230         if (this.position != position) {
231             this.position = position;
232             notifyListeners(new TitleChangeEvent(this));
233         }
234     }
235 
236     /**
237      * Returns the horizontal alignment of the title.
238      *
239      * @return The horizontal alignment (never <code>null</code>).
240      */
241     public HorizontalAlignment getHorizontalAlignment() {
242         return this.horizontalAlignment;
243     }
244 
245     /**
246      * Sets the horizontal alignment for the title and sends a 
247      * {@link TitleChangeEvent} to all registered listeners.
248      *
249      * @param alignment  the horizontal alignment (<code>null</code> not 
250      *                   permitted).
251      */
252     public void setHorizontalAlignment(HorizontalAlignment alignment) {
253         if (alignment == null) {
254             throw new IllegalArgumentException  ("Null 'alignment' argument.");
255         }
256         if (this.horizontalAlignment != alignment) {
257             this.horizontalAlignment = alignment;
258             notifyListeners(new TitleChangeEvent(this));
259         }
260     }
261 
262     /**
263      * Returns the vertical alignment of the title.
264      *
265      * @return The vertical alignment (never <code>null</code>).
266      */
267     public VerticalAlignment getVerticalAlignment() {
268         return this.verticalAlignment;
269     }
270 
271     /**
272      * Sets the vertical alignment for the title, and notifies any registered
273      * listeners of the change.
274      *
275      * @param alignment  the new vertical alignment (TOP, MIDDLE or BOTTOM, 
276      *                   <code>null</code> not permitted).
277      */
278     public void setVerticalAlignment(VerticalAlignment alignment) {
279         if (alignment == null) {
280             throw new IllegalArgumentException  ("Null 'alignment' argument.");
281         }
282         if (this.verticalAlignment != alignment) {
283             this.verticalAlignment = alignment;
284             notifyListeners(new TitleChangeEvent(this));
285         }
286     }
287 
288     /**
289      * Returns the flag that indicates whether or not the notification 
290      * mechanism is enabled.
291      *
292      * @return The flag.
293      */
294     public boolean getNotify() {
295         return this.notify;
296     }
297 
298     /**
299      * Sets the flag that indicates whether or not the notification mechanism
300      * is enabled.  There are certain situations (such as cloning) where you
301      * want to turn notification off temporarily.
302      *
303      * @param flag  the new value of the flag.
304      */
305     public void setNotify(boolean flag) {
306         this.notify = flag;
307         if (flag) {
308             notifyListeners(new TitleChangeEvent(this));   
309         }
310     }
311 
312     /**
313      * Draws the title on a Java 2D graphics device (such as the screen or a 
314      * printer).
315      *
316      * @param g2  the graphics device.
317      * @param area  the area allocated for the title (subclasses should not
318      *              draw outside this area).
319      */
320     public abstract void draw(Graphics2D   g2, Rectangle2D   area);
321 
322     /**
323      * Returns a clone of the title.
324      * <P>
325      * One situation when this is useful is when editing the title properties -
326      * you can edit a clone, and then it is easier to cancel the changes if
327      * necessary.
328      *
329      * @return A clone of the title.
330      *
331      * @throws CloneNotSupportedException not thrown by this class, but it may 
332      *         be thrown by subclasses.
333      */
334     public Object   clone() throws CloneNotSupportedException   {
335 
336         Title duplicate = (Title) super.clone();
337         duplicate.listenerList = new EventListenerList  ();
338         // RectangleInsets is immutable => same reference in clone OK
339         return duplicate;
340     }
341 
342     /**
343      * Registers an object for notification of changes to the title.
344      *
345      * @param listener  the object that is being registered.
346      */
347     public void addChangeListener(TitleChangeListener listener) {
348         this.listenerList.add(TitleChangeListener.class, listener);
349     }
350 
351     /**
352      * Unregisters an object for notification of changes to the chart title.
353      *
354      * @param listener  the object that is being unregistered.
355      */
356     public void removeChangeListener(TitleChangeListener listener) {
357         this.listenerList.remove(TitleChangeListener.class, listener);
358     }
359 
360     /**
361      * Notifies all registered listeners that the chart title has changed in 
362      * some way.
363      *
364      * @param event  an object that contains information about the change to 
365      *               the title.
366      */
367     protected void notifyListeners(TitleChangeEvent event) {
368         if (this.notify) {
369             Object  [] listeners = this.listenerList.getListenerList();
370             for (int i = listeners.length - 2; i >= 0; i -= 2) {
371                 if (listeners[i] == TitleChangeListener.class) {
372                     ((TitleChangeListener) listeners[i + 1]).titleChanged(
373                         event
374                     );
375                 }
376             }
377         }
378     }
379 
380     /**
381      * Tests an object for equality with this title.
382      *
383      * @param obj  the object (<code>null</code> not permitted).
384      *
385      * @return <code>true</code> or <code>false</code>.
386      */
387     public boolean equals(Object   obj) {
388         if (obj == this) {
389             return true;
390         }
391         if (!(obj instanceof Title)) {
392             return false;
393         }
394         if (!super.equals(obj)) {
395             return false;   
396         }
397         Title that = (Title) obj;
398         if (this.position != that.position) {
399             return false;
400         }
401         if (this.horizontalAlignment != that.horizontalAlignment) {
402             return false;
403         }
404         if (this.verticalAlignment != that.verticalAlignment) {
405             return false;
406         }
407         if (this.notify != that.notify) {
408             return false;
409         }
410         return true;
411     }
412 
413     /**
414      * Returns a hashcode for the title.
415      * 
416      * @return The hashcode.
417      */
418     public int hashCode() {
419         int result = 193;
420         result = 37 * result + ObjectUtilities.hashCode(this.position);    
421         result = 37 * result 
422             + ObjectUtilities.hashCode(this.horizontalAlignment);    
423         result = 37 * result + ObjectUtilities.hashCode(this.verticalAlignment);
424         return result;
425     }
426         
427     /**
428      * Provides serialization support.
429      *
430      * @param stream  the output stream.
431      *
432      * @throws IOException  if there is an I/O error.
433      */
434     private void writeObject(ObjectOutputStream   stream) throws IOException   {
435         stream.defaultWriteObject();
436     }
437 
438     /**
439      * Provides serialization support.
440      *
441      * @param stream  the input stream.
442      *
443      * @throws IOException  if there is an I/O error.
444      * @throws ClassNotFoundException  if there is a classpath problem.
445      */
446     private void readObject(ObjectInputStream   stream) 
447         throws IOException  , ClassNotFoundException   {
448         stream.defaultReadObject();
449         this.listenerList = new EventListenerList  ();
450     }
451 
452 }
453
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