Source for org.jfree.data.general.Series

   1: /* ===========================================================
   2:  * JFreeChart : a free chart library for the Java(tm) platform
   3:  * ===========================================================
   4:  *
   5:  * (C) Copyright 2000-2007, 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:  * Series.java
  29:  * -----------
  30:  * (C) Copyright 2001-2007, by Object Refinery Limited.
  31:  *
  32:  * Original Author:  David Gilbert (for Object Refinery Limited);
  33:  * Contributor(s):   -;
  34:  *
  35:  * Changes
  36:  * -------
  37:  * 15-Nov-2001 : Version 1 (DG);
  38:  * 29-Nov-2001 : Added cloning and property change support (DG);
  39:  * 30-Jan-2002 : Added a description attribute and changed the constructors to 
  40:  *               protected (DG);
  41:  * 07-Oct-2002 : Fixed errors reported by Checkstyle (DG);
  42:  * 13-Mar-2003 : Implemented Serializable (DG);
  43:  * 01-May-2003 : Added equals() method (DG);
  44:  * 26-Jun-2003 : Changed listener list to use EventListenerList - see bug 
  45:  *               757027 (DG);
  46:  * 15-Oct-2003 : Added a flag to control whether or not change events are sent 
  47:  *               to registered listeners (DG);
  48:  * 19-May-2005 : Made abstract (DG);
  49:  * ------------- JFREECHART 1.0.x ---------------------------------------------
  50:  * 04-May-2006 : Updated API docs (DG);
  51:  * 26-Sep-2007 : Added isEmpty() and getItemCount() methods (DG);
  52:  * 
  53:  */
  54: 
  55: package org.jfree.data.general;
  56: 
  57: import java.beans.PropertyChangeListener;
  58: import java.beans.PropertyChangeSupport;
  59: import java.io.Serializable;
  60: 
  61: import javax.swing.event.EventListenerList;
  62: 
  63: import org.jfree.util.ObjectUtilities;
  64: 
  65: /**
  66:  * Base class representing a data series.  Subclasses are left to implement the
  67:  * actual data structures.
  68:  * <P>
  69:  * The series has two properties ("Key" and "Description") for which you can
  70:  * register a <code>PropertyChangeListener</code>.
  71:  * <P>
  72:  * You can also register a {@link SeriesChangeListener} to receive notification 
  73:  * of changes to the series data.
  74:  */
  75: public abstract class Series implements Cloneable, Serializable {
  76: 
  77:     /** For serialization. */
  78:     private static final long serialVersionUID = -6906561437538683581L;
  79:     
  80:     /** The key for the series. */
  81:     private Comparable key;
  82: 
  83:     /** A description of the series. */
  84:     private String description;
  85: 
  86:     /** Storage for registered change listeners. */
  87:     private EventListenerList listeners;
  88: 
  89:     /** Object to support property change notification. */
  90:     private PropertyChangeSupport propertyChangeSupport;
  91: 
  92:     /** A flag that controls whether or not changes are notified. */
  93:     private boolean notify;
  94: 
  95:     /**
  96:      * Creates a new series with the specified key.  
  97:      *
  98:      * @param key  the series key (<code>null</code> not permitted).
  99:      */
 100:     protected Series(Comparable key) {
 101:         this(key, null);
 102:     }
 103: 
 104:     /**
 105:      * Creates a new series with the specified key and description.
 106:      *
 107:      * @param key  the series key (<code>null</code> NOT permitted).
 108:      * @param description  the series description (<code>null</code> permitted).
 109:      */
 110:     protected Series(Comparable key, String description) {
 111:         if (key == null) {
 112:             throw new IllegalArgumentException("Null 'key' argument.");
 113:         }
 114:         this.key = key;
 115:         this.description = description;
 116:         this.listeners = new EventListenerList();
 117:         this.propertyChangeSupport = new PropertyChangeSupport(this);
 118:         this.notify = true;   
 119:     }
 120: 
 121:     /**
 122:      * Returns the key for the series.
 123:      *
 124:      * @return The series key (never <code>null</code>).
 125:      * 
 126:      * @see #setKey(Comparable)
 127:      */
 128:     public Comparable getKey() {
 129:         return this.key;
 130:     }
 131: 
 132:     /**
 133:      * Sets the key for the series and sends a <code>PropertyChangeEvent</code> 
 134:      * (with the property name "Key") to all registered listeners.
 135:      *
 136:      * @param key  the key (<code>null</code> not permitted).
 137:      * 
 138:      * @see #getKey()
 139:      */
 140:     public void setKey(Comparable key) {
 141:         if (key == null) {
 142:             throw new IllegalArgumentException("Null 'key' argument.");
 143:         }
 144:         Comparable old = this.key;
 145:         this.key = key;
 146:         this.propertyChangeSupport.firePropertyChange("Key", old, key);
 147:     }
 148: 
 149:     /**
 150:      * Returns a description of the series.
 151:      *
 152:      * @return The series description (possibly <code>null</code>).
 153:      * 
 154:      * @see #setDescription(String)
 155:      */
 156:     public String getDescription() {
 157:         return this.description;
 158:     }
 159: 
 160:     /**
 161:      * Sets the description of the series and sends a 
 162:      * <code>PropertyChangeEvent</code> to all registered listeners.
 163:      *
 164:      * @param description  the description (<code>null</code> permitted).
 165:      * 
 166:      * @see #getDescription()
 167:      */
 168:     public void setDescription(String description) {
 169:         String old = this.description;
 170:         this.description = description;
 171:         this.propertyChangeSupport.firePropertyChange("Description", old, 
 172:                 description);
 173:     }
 174: 
 175:     /**
 176:      * Returns the flag that controls whether or not change events are sent to 
 177:      * registered listeners.
 178:      * 
 179:      * @return A boolean.
 180:      * 
 181:      * @see #setNotify(boolean)
 182:      */
 183:     public boolean getNotify() {
 184:         return this.notify;
 185:     }
 186:     
 187:     /**
 188:      * Sets the flag that controls whether or not change events are sent to 
 189:      * registered listeners.
 190:      * 
 191:      * @param notify  the new value of the flag.
 192:      * 
 193:      * @see #getNotify()
 194:      */
 195:     public void setNotify(boolean notify) {
 196:         if (this.notify != notify) {
 197:             this.notify = notify;
 198:             fireSeriesChanged();
 199:         }
 200:     }
 201:     
 202:     /**
 203:      * Returns <code>true</code> if the series contains no data items, and
 204:      * <code>false</code> otherwise.
 205:      * 
 206:      * @return A boolean.
 207:      * 
 208:      * @since 1.0.7
 209:      */
 210:     public boolean isEmpty() {
 211:         return (getItemCount() == 0);
 212:     }
 213:     
 214:     /**
 215:      * Returns the number of data items in the series.
 216:      * 
 217:      * @return The number of data items in the series.
 218:      */
 219:     public abstract int getItemCount();
 220:     
 221:     /**
 222:      * Returns a clone of the series.
 223:      * <P>
 224:      * Notes:
 225:      * <ul>
 226:      * <li>No need to clone the name or description, since String object is 
 227:      * immutable.</li>
 228:      * <li>We set the listener list to empty, since the listeners did not 
 229:      * register with the clone.</li>
 230:      * <li>Same applies to the PropertyChangeSupport instance.</li>
 231:      * </ul>
 232:      *
 233:      * @return A clone of the series.
 234:      * 
 235:      * @throws CloneNotSupportedException  not thrown by this class, but 
 236:      *         subclasses may differ.
 237:      */
 238:     public Object clone() throws CloneNotSupportedException {
 239: 
 240:         Series clone = (Series) super.clone();
 241:         clone.listeners = new EventListenerList();
 242:         clone.propertyChangeSupport = new PropertyChangeSupport(clone);
 243:         return clone;
 244: 
 245:     }
 246: 
 247:     /**
 248:      * Tests the series for equality with another object.
 249:      *
 250:      * @param obj  the object (<code>null</code> permitted).
 251:      *
 252:      * @return <code>true</code> or <code>false</code>.
 253:      */
 254:     public boolean equals(Object obj) {
 255:         if (obj == this) {
 256:             return true;
 257:         }
 258:         if (!(obj instanceof Series)) {
 259:             return false;
 260:         }
 261:         Series that = (Series) obj;
 262:         if (!getKey().equals(that.getKey())) {
 263:             return false;
 264:         }
 265:         if (!ObjectUtilities.equal(getDescription(), that.getDescription())) {
 266:             return false;
 267:         }
 268:         return true;
 269:     }
 270: 
 271:     /**
 272:      * Returns a hash code.
 273:      * 
 274:      * @return A hash code.
 275:      */
 276:     public int hashCode() {
 277:         int result;
 278:         result = this.key.hashCode();
 279:         result = 29 * result + (this.description != null 
 280:                 ? this.description.hashCode() : 0);
 281:         return result;
 282:     }
 283: 
 284:     /**
 285:      * Registers an object with this series, to receive notification whenever 
 286:      * the series changes.
 287:      * <P>
 288:      * Objects being registered must implement the {@link SeriesChangeListener} 
 289:      * interface.
 290:      *
 291:      * @param listener  the listener to register.
 292:      */
 293:     public void addChangeListener(SeriesChangeListener listener) {
 294:         this.listeners.add(SeriesChangeListener.class, listener);
 295:     }
 296: 
 297:     /**
 298:      * Deregisters an object, so that it not longer receives notification 
 299:      * whenever the series changes.
 300:      *
 301:      * @param listener  the listener to deregister.
 302:      */
 303:     public void removeChangeListener(SeriesChangeListener listener) {
 304:         this.listeners.remove(SeriesChangeListener.class, listener);
 305:     }
 306: 
 307:     /**
 308:      * General method for signalling to registered listeners that the series
 309:      * has been changed.
 310:      */
 311:     public void fireSeriesChanged() {
 312:         if (this.notify) {
 313:             notifyListeners(new SeriesChangeEvent(this));
 314:         }
 315:     }
 316: 
 317:     /**
 318:      * Sends a change event to all registered listeners.
 319:      *
 320:      * @param event  contains information about the event that triggered the 
 321:      *               notification.
 322:      */
 323:     protected void notifyListeners(SeriesChangeEvent event) {
 324: 
 325:         Object[] listenerList = this.listeners.getListenerList();
 326:         for (int i = listenerList.length - 2; i >= 0; i -= 2) {
 327:             if (listenerList[i] == SeriesChangeListener.class) {
 328:                 ((SeriesChangeListener) listenerList[i + 1]).seriesChanged(
 329:                         event);
 330:             }
 331:         }
 332: 
 333:     }
 334: 
 335:     /**
 336:      * Adds a property change listener to the series.
 337:      *
 338:      * @param listener  the listener.
 339:      */
 340:     public void addPropertyChangeListener(PropertyChangeListener listener) {
 341:         this.propertyChangeSupport.addPropertyChangeListener(listener);
 342:     }
 343: 
 344:     /**
 345:      * Removes a property change listener from the series.
 346:      *
 347:      * @param listener The listener.
 348:      */
 349:     public void removePropertyChangeListener(PropertyChangeListener listener) {
 350:         this.propertyChangeSupport.removePropertyChangeListener(listener);
 351:     }
 352: 
 353:     /**
 354:      * Fires a property change event.
 355:      *
 356:      * @param property  the property key.
 357:      * @param oldValue  the old value.
 358:      * @param newValue  the new value.
 359:      */
 360:     protected void firePropertyChange(String property, Object oldValue, 
 361:             Object newValue) {
 362:         this.propertyChangeSupport.firePropertyChange(property, oldValue, 
 363:                 newValue);
 364:     }
 365: 
 366: }