001: /* ===========================================================
002: * JFreeChart : a free chart library for the Java(tm) platform
003: * ===========================================================
004: *
005: * (C) Copyright 2000-2006, 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: * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
025: * in the United States and other countries.]
026: *
027: * --------------------
028: * AbstractDataset.java
029: * --------------------
030: * (C)opyright 2000-2006, by Object Refinery Limited.
031: *
032: * Original Author: David Gilbert (for Object Refinery Limited);
033: * Contributor(s): Nicolas Brodu (for Astrium and EADS Corporate Research
034: * Center);
035: *
036: * $Id: AbstractDataset.java,v 1.5.2.2 2006/07/26 12:14:20 mungady Exp $
037: *
038: * Changes (from 21-Aug-2001)
039: * --------------------------
040: * 21-Aug-2001 : Added standard header. Fixed DOS encoding problem (DG);
041: * 18-Sep-2001 : Updated e-mail address in header (DG);
042: * 15-Oct-2001 : Moved to new package (com.jrefinery.data.*) (DG);
043: * 22-Oct-2001 : Renamed DataSource.java --> Dataset.java etc. (DG);
044: * 17-Nov-2001 : Changed constructor from public to protected, created new
045: * AbstractSeriesDataset class and transferred series-related
046: * methods, updated Javadoc comments (DG);
047: * 04-Mar-2002 : Updated import statements (DG);
048: * 11-Jun-2002 : Updated for change in the event constructor (DG);
049: * 07-Aug-2002 : Changed listener list to use
050: * javax.swing.event.EventListenerList (DG);
051: * 04-Oct-2002 : Fixed errors reported by Checkstyle (DG);
052: * 27-Mar-2003 : Implemented Serializable (DG);
053: * 18-Aug-2003 : Implemented Cloneable (DG);
054: * 08-Sep-2003 : Serialization fixes (NB);
055: * 11-Sep-2003 : Cloning Fixes (NB);
056: * 01-Jun-2005 : Added hasListener() method for unit testing (DG);
057: *
058: */
059:
060: package org.jfree.data.general;
061:
062: import java.io.IOException;
063: import java.io.InvalidObjectException;
064: import java.io.ObjectInputStream;
065: import java.io.ObjectInputValidation;
066: import java.io.ObjectOutputStream;
067: import java.io.Serializable;
068: import java.util.Arrays;
069: import java.util.EventListener;
070: import java.util.List;
071:
072: import javax.swing.event.EventListenerList;
073:
074: /**
075: * An abstract implementation of the {@link Dataset} interface, containing a
076: * mechanism for registering change listeners.
077: */
078: public abstract class AbstractDataset implements Dataset, Cloneable,
079: Serializable, ObjectInputValidation {
080:
081: /** For serialization. */
082: private static final long serialVersionUID = 1918768939869230744L;
083:
084: /** The group that the dataset belongs to. */
085: private DatasetGroup group;
086:
087: /** Storage for registered change listeners. */
088: private transient EventListenerList listenerList;
089:
090: /**
091: * Constructs a dataset. By default, the dataset is assigned to its own
092: * group.
093: */
094: protected AbstractDataset() {
095: this .group = new DatasetGroup();
096: this .listenerList = new EventListenerList();
097: }
098:
099: /**
100: * Returns the dataset group for the dataset.
101: *
102: * @return The group.
103: */
104: public DatasetGroup getGroup() {
105: return this .group;
106: }
107:
108: /**
109: * Sets the dataset group for the dataset.
110: *
111: * @param group the group (<code>null</code> not permitted).
112: */
113: public void setGroup(DatasetGroup group) {
114: if (group == null) {
115: throw new IllegalArgumentException("Null 'group' argument.");
116: }
117: this .group = group;
118: }
119:
120: /**
121: * Registers an object to receive notification of changes to the dataset.
122: *
123: * @param listener the object to register.
124: */
125: public void addChangeListener(DatasetChangeListener listener) {
126: this .listenerList.add(DatasetChangeListener.class, listener);
127: }
128:
129: /**
130: * Deregisters an object so that it no longer receives notification of
131: * changes to the dataset.
132: *
133: * @param listener the object to deregister.
134: */
135: public void removeChangeListener(DatasetChangeListener listener) {
136: this .listenerList.remove(DatasetChangeListener.class, listener);
137: }
138:
139: /**
140: * Returns <code>true</code> if the specified object is registered with
141: * the dataset as a listener. Most applications won't need to call this
142: * method, it exists mainly for use by unit testing code.
143: *
144: * @param listener the listener.
145: *
146: * @return A boolean.
147: */
148: public boolean hasListener(EventListener listener) {
149: List list = Arrays.asList(this .listenerList.getListenerList());
150: return list.contains(listener);
151: }
152:
153: /**
154: * Notifies all registered listeners that the dataset has changed.
155: */
156: protected void fireDatasetChanged() {
157: notifyListeners(new DatasetChangeEvent(this , this ));
158: }
159:
160: /**
161: * Notifies all registered listeners that the dataset has changed.
162: *
163: * @param event contains information about the event that triggered the
164: * notification.
165: */
166: protected void notifyListeners(DatasetChangeEvent event) {
167:
168: Object[] listeners = this .listenerList.getListenerList();
169: for (int i = listeners.length - 2; i >= 0; i -= 2) {
170: if (listeners[i] == DatasetChangeListener.class) {
171: ((DatasetChangeListener) listeners[i + 1])
172: .datasetChanged(event);
173: }
174: }
175:
176: }
177:
178: /**
179: * Returns a clone of the dataset. The cloned dataset will NOT include the
180: * {@link DatasetChangeListener} references that have been registered with
181: * this dataset.
182: *
183: * @return A clone.
184: *
185: * @throws CloneNotSupportedException if the dataset does not support
186: * cloning.
187: */
188: public Object clone() throws CloneNotSupportedException {
189: AbstractDataset clone = (AbstractDataset) super .clone();
190: clone.listenerList = new EventListenerList();
191: return clone;
192: }
193:
194: /**
195: * Handles serialization.
196: *
197: * @param stream the output stream.
198: *
199: * @throws IOException if there is an I/O problem.
200: */
201: private void writeObject(ObjectOutputStream stream)
202: throws IOException {
203: stream.defaultWriteObject();
204: }
205:
206: /**
207: * Restores a serialized object.
208: *
209: * @param stream the input stream.
210: *
211: * @throws IOException if there is an I/O problem.
212: * @throws ClassNotFoundException if there is a problem loading a class.
213: */
214: private void readObject(ObjectInputStream stream)
215: throws IOException, ClassNotFoundException {
216: stream.defaultReadObject();
217: this .listenerList = new EventListenerList();
218: stream.registerValidation(this , 10); // see comments about priority of
219: // 10 in validateObject()
220: }
221:
222: /**
223: * Validates the object. We use this opportunity to call listeners who have
224: * registered during the deserialization process, as listeners are not
225: * serialized. This method is called by the serialization system after the
226: * entire graph is read.
227: *
228: * This object has registered itself to the system with a priority of 10.
229: * Other callbacks may register with a higher priority number to be called
230: * before this object, or with a lower priority number to be called after
231: * the listeners were notified.
232: *
233: * All listeners are supposed to have register by now, either in their
234: * readObject or validateObject methods. Notify them that this dataset has
235: * changed.
236: *
237: * @exception InvalidObjectException If the object cannot validate itself.
238: */
239: public void validateObject() throws InvalidObjectException {
240: fireDatasetChanged();
241: }
242:
243: }
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