001    /* ===========================================================
002     * JFreeChart : a free chart library for the Java(tm) platform
003     * ===========================================================
004     *
005     * (C) Copyright 2000-2011, by Object Refinery Limited and Contributors.
006     *
007     * Project Info:  http://www.jfree.org/jfreechart/index.html
008     *
009     * This library is free software; you can redistribute it and/or modify it
010     * under the terms of the GNU Lesser General Public License as published by
011     * the Free Software Foundation; either version 2.1 of the License, or
012     * (at your option) any later version.
013     *
014     * This library is distributed in the hope that it will be useful, but
015     * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016     * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017     * License for more details.
018     *
019     * You should have received a copy of the GNU Lesser General Public
020     * License along with this library; if not, write to the Free Software
021     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
022     * USA.
023     *
024     * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
025     * Other names may be trademarks of their respective owners.]
026     *
027     * -----------
028     * Series.java
029     * -----------
030     * (C) Copyright 2001-2011, by Object Refinery Limited.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   -;
034     *
035     * Changes
036     * -------
037     * 15-Nov-2001 : Version 1 (DG);
038     * 29-Nov-2001 : Added cloning and property change support (DG);
039     * 30-Jan-2002 : Added a description attribute and changed the constructors to
040     *               protected (DG);
041     * 07-Oct-2002 : Fixed errors reported by Checkstyle (DG);
042     * 13-Mar-2003 : Implemented Serializable (DG);
043     * 01-May-2003 : Added equals() method (DG);
044     * 26-Jun-2003 : Changed listener list to use EventListenerList - see bug
045     *               757027 (DG);
046     * 15-Oct-2003 : Added a flag to control whether or not change events are sent
047     *               to registered listeners (DG);
048     * 19-May-2005 : Made abstract (DG);
049     * ------------- JFREECHART 1.0.x ---------------------------------------------
050     * 04-May-2006 : Updated API docs (DG);
051     * 26-Sep-2007 : Added isEmpty() and getItemCount() methods (DG);
052     * 16-Oct-2011 : Added vetoable property change support for series name (DG);
053     */
054    
055    package org.jfree.data.general;
056    
057    import java.beans.PropertyChangeListener;
058    import java.beans.PropertyChangeSupport;
059    import java.beans.PropertyVetoException;
060    import java.beans.VetoableChangeListener;
061    import java.beans.VetoableChangeSupport;
062    import java.io.Serializable;
063    
064    import javax.swing.event.EventListenerList;
065    
066    import org.jfree.chart.util.ParamChecks;
067    import org.jfree.util.ObjectUtilities;
068    
069    /**
070     * Base class representing a data series.  Subclasses are left to implement the
071     * actual data structures.
072     * <P>
073     * The series has two properties ("Key" and "Description") for which you can
074     * register a <code>PropertyChangeListener</code>.
075     * <P>
076     * You can also register a {@link SeriesChangeListener} to receive notification
077     * of changes to the series data.
078     */
079    public abstract class Series implements Cloneable, Serializable {
080    
081        /** For serialization. */
082        private static final long serialVersionUID = -6906561437538683581L;
083    
084        /** The key for the series. */
085        private Comparable key;
086    
087        /** A description of the series. */
088        private String description;
089    
090        /** Storage for registered change listeners. */
091        private EventListenerList listeners;
092    
093        /** Object to support property change notification. */
094        private PropertyChangeSupport propertyChangeSupport;
095    
096        /** Object to support property change notification. */
097        private VetoableChangeSupport vetoableChangeSupport;
098    
099        /** A flag that controls whether or not changes are notified. */
100        private boolean notify;
101    
102        /**
103         * Creates a new series with the specified key.
104         *
105         * @param key  the series key (<code>null</code> not permitted).
106         */
107        protected Series(Comparable key) {
108            this(key, null);
109        }
110    
111        /**
112         * Creates a new series with the specified key and description.
113         *
114         * @param key  the series key (<code>null</code> NOT permitted).
115         * @param description  the series description (<code>null</code> permitted).
116         */
117        protected Series(Comparable key, String description) {
118            if (key == null) {
119                throw new IllegalArgumentException("Null 'key' argument.");
120            }
121            this.key = key;
122            this.description = description;
123            this.listeners = new EventListenerList();
124            this.propertyChangeSupport = new PropertyChangeSupport(this);
125            this.vetoableChangeSupport = new VetoableChangeSupport(this);
126            this.notify = true;
127        }
128    
129        /**
130         * Returns the key for the series.
131         *
132         * @return The series key (never <code>null</code>).
133         *
134         * @see #setKey(Comparable)
135         */
136        public Comparable getKey() {
137            return this.key;
138        }
139    
140        /**
141         * Sets the key for the series and sends a <code>VetoableChangeEvent</code>
142         * (with the property name "Key") to all registered listeners.  For 
143         * backwards compatibility, this method also fires a regular 
144         * <code>PropertyChangeEvent</code>.
145         *
146         * @param key  the key (<code>null</code> not permitted).
147         *
148         * @see #getKey()
149         */
150        public void setKey(Comparable key) {
151            ParamChecks.nullNotPermitted(key, "key");
152            Comparable old = this.key;
153            try {
154                // if this series belongs to a dataset, the dataset might veto the
155                // change if it results in two series within the dataset having the
156                // same key
157                this.vetoableChangeSupport.fireVetoableChange("Key", old, key);
158                this.key = key;
159                // prior to 1.0.14, we just fired a PropertyChange - so we need to
160                // keep doing this
161                this.propertyChangeSupport.firePropertyChange("Key", old, key);
162            } catch (PropertyVetoException e) {
163                throw new IllegalArgumentException(e.getMessage());
164            }
165        }
166    
167        /**
168         * Returns a description of the series.
169         *
170         * @return The series description (possibly <code>null</code>).
171         *
172         * @see #setDescription(String)
173         */
174        public String getDescription() {
175            return this.description;
176        }
177    
178        /**
179         * Sets the description of the series and sends a
180         * <code>PropertyChangeEvent</code> to all registered listeners.
181         *
182         * @param description  the description (<code>null</code> permitted).
183         *
184         * @see #getDescription()
185         */
186        public void setDescription(String description) {
187            String old = this.description;
188            this.description = description;
189            this.propertyChangeSupport.firePropertyChange("Description", old,
190                    description);
191        }
192    
193        /**
194         * Returns the flag that controls whether or not change events are sent to
195         * registered listeners.
196         *
197         * @return A boolean.
198         *
199         * @see #setNotify(boolean)
200         */
201        public boolean getNotify() {
202            return this.notify;
203        }
204    
205        /**
206         * Sets the flag that controls whether or not change events are sent to
207         * registered listeners.
208         *
209         * @param notify  the new value of the flag.
210         *
211         * @see #getNotify()
212         */
213        public void setNotify(boolean notify) {
214            if (this.notify != notify) {
215                this.notify = notify;
216                fireSeriesChanged();
217            }
218        }
219    
220        /**
221         * Returns <code>true</code> if the series contains no data items, and
222         * <code>false</code> otherwise.
223         *
224         * @return A boolean.
225         *
226         * @since 1.0.7
227         */
228        public boolean isEmpty() {
229            return (getItemCount() == 0);
230        }
231    
232        /**
233         * Returns the number of data items in the series.
234         *
235         * @return The number of data items in the series.
236         */
237        public abstract int getItemCount();
238    
239        /**
240         * Returns a clone of the series.
241         * <P>
242         * Notes:
243         * <ul>
244         * <li>No need to clone the name or description, since String object is
245         * immutable.</li>
246         * <li>We set the listener list to empty, since the listeners did not
247         * register with the clone.</li>
248         * <li>Same applies to the PropertyChangeSupport instance.</li>
249         * </ul>
250         *
251         * @return A clone of the series.
252         *
253         * @throws CloneNotSupportedException  not thrown by this class, but
254         *         subclasses may differ.
255         */
256        public Object clone() throws CloneNotSupportedException {
257            Series clone = (Series) super.clone();
258            clone.listeners = new EventListenerList();
259            clone.propertyChangeSupport = new PropertyChangeSupport(clone);
260            clone.vetoableChangeSupport = new VetoableChangeSupport(clone);
261            return clone;
262        }
263    
264        /**
265         * Tests the series for equality with another object.
266         *
267         * @param obj  the object (<code>null</code> permitted).
268         *
269         * @return <code>true</code> or <code>false</code>.
270         */
271        public boolean equals(Object obj) {
272            if (obj == this) {
273                return true;
274            }
275            if (!(obj instanceof Series)) {
276                return false;
277            }
278            Series that = (Series) obj;
279            if (!getKey().equals(that.getKey())) {
280                return false;
281            }
282            if (!ObjectUtilities.equal(getDescription(), that.getDescription())) {
283                return false;
284            }
285            return true;
286        }
287    
288        /**
289         * Returns a hash code.
290         *
291         * @return A hash code.
292         */
293        public int hashCode() {
294            int result;
295            result = this.key.hashCode();
296            result = 29 * result + (this.description != null
297                    ? this.description.hashCode() : 0);
298            return result;
299        }
300    
301        /**
302         * Registers an object with this series, to receive notification whenever
303         * the series changes.
304         * <P>
305         * Objects being registered must implement the {@link SeriesChangeListener}
306         * interface.
307         *
308         * @param listener  the listener to register.
309         */
310        public void addChangeListener(SeriesChangeListener listener) {
311            this.listeners.add(SeriesChangeListener.class, listener);
312        }
313    
314        /**
315         * Deregisters an object, so that it not longer receives notification
316         * whenever the series changes.
317         *
318         * @param listener  the listener to deregister.
319         */
320        public void removeChangeListener(SeriesChangeListener listener) {
321            this.listeners.remove(SeriesChangeListener.class, listener);
322        }
323    
324        /**
325         * General method for signalling to registered listeners that the series
326         * has been changed.
327         */
328        public void fireSeriesChanged() {
329            if (this.notify) {
330                notifyListeners(new SeriesChangeEvent(this));
331            }
332        }
333    
334        /**
335         * Sends a change event to all registered listeners.
336         *
337         * @param event  contains information about the event that triggered the
338         *               notification.
339         */
340        protected void notifyListeners(SeriesChangeEvent event) {
341    
342            Object[] listenerList = this.listeners.getListenerList();
343            for (int i = listenerList.length - 2; i >= 0; i -= 2) {
344                if (listenerList[i] == SeriesChangeListener.class) {
345                    ((SeriesChangeListener) listenerList[i + 1]).seriesChanged(
346                            event);
347                }
348            }
349    
350        }
351    
352        /**
353         * Adds a property change listener to the series.
354         *
355         * @param listener  the listener.
356         */
357        public void addPropertyChangeListener(PropertyChangeListener listener) {
358            this.propertyChangeSupport.addPropertyChangeListener(listener);
359        }
360    
361        /**
362         * Removes a property change listener from the series.
363         *
364         * @param listener  the listener.
365         */
366        public void removePropertyChangeListener(PropertyChangeListener listener) {
367            this.propertyChangeSupport.removePropertyChangeListener(listener);
368        }
369    
370        /**
371         * Fires a property change event.
372         *
373         * @param property  the property key.
374         * @param oldValue  the old value.
375         * @param newValue  the new value.
376         */
377        protected void firePropertyChange(String property, Object oldValue,
378                Object newValue) {
379            this.propertyChangeSupport.firePropertyChange(property, oldValue,
380                    newValue);
381        }
382        
383        /**
384         * Adds a vetoable property change listener to the series.
385         *
386         * @param listener  the listener.
387         * 
388         * @since 1.0.14
389         */
390        public void addVetoableChangeListener(VetoableChangeListener listener) {
391            this.vetoableChangeSupport.addVetoableChangeListener(listener);
392        }
393    
394        /**
395         * Removes a vetoable property change listener from the series.
396         *
397         * @param listener  the listener.
398         * 
399         * @since 1.0.14 
400         */
401        public void removeVetoableChangeListener(VetoableChangeListener listener) {
402            this.vetoableChangeSupport.removeVetoableChangeListener(listener);
403        }    
404    
405        /**
406         * Fires a vetoable property change event.
407         *
408         * @param property  the property key.
409         * @param oldValue  the old value.
410         * @param newValue  the new value.
411         */
412        protected void fireVetoableChange(String property, Object oldValue,
413                Object newValue) throws PropertyVetoException {
414            this.vetoableChangeSupport.fireVetoableChange(property, oldValue,
415                    newValue);
416        }
417    
418    }