/* ===========================================================
* JFreeChart : a free chart library for the Java(tm) platform
* ===========================================================
*
* (C) Copyright 2000-2011, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jfreechart/index.html
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
* Other names may be trademarks of their respective owners.]
*
* --------------------
* AbstractDataset.java
* --------------------
* (C)opyright 2000-2008, by Object Refinery Limited.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): Nicolas Brodu (for Astrium and EADS Corporate Research
* Center);
*
* Changes (from 21-Aug-2001)
* --------------------------
* 21-Aug-2001 : Added standard header. Fixed DOS encoding problem (DG);
* 18-Sep-2001 : Updated e-mail address in header (DG);
* 15-Oct-2001 : Moved to new package (com.jrefinery.data.*) (DG);
* 22-Oct-2001 : Renamed DataSource.java --> Dataset.java etc. (DG);
* 17-Nov-2001 : Changed constructor from public to protected, created new
* AbstractSeriesDataset class and transferred series-related
* methods, updated Javadoc comments (DG);
* 04-Mar-2002 : Updated import statements (DG);
* 11-Jun-2002 : Updated for change in the event constructor (DG);
* 07-Aug-2002 : Changed listener list to use
* javax.swing.event.EventListenerList (DG);
* 04-Oct-2002 : Fixed errors reported by Checkstyle (DG);
* 27-Mar-2003 : Implemented Serializable (DG);
* 18-Aug-2003 : Implemented Cloneable (DG);
* 08-Sep-2003 : Serialization fixes (NB);
* 11-Sep-2003 : Cloning Fixes (NB);
* 01-Jun-2005 : Added hasListener() method for unit testing (DG);
*
*/
package org.jfree.data.general;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.ObjectInputValidation;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Arrays;
import java.util.EventListener;
import java.util.List;
import javax.swing.event.EventListenerList;
/**
* An abstract implementation of the {@link Dataset} interface, containing a
* mechanism for registering change listeners.
*/
public abstract class AbstractDataset implements Dataset, Cloneable,
Serializable, ObjectInputValidation {
/** For serialization. */
private static final long serialVersionUID = 1918768939869230744L;
/** The group that the dataset belongs to. */
private DatasetGroup group;
/** Storage for registered change listeners. */
private transient EventListenerList listenerList;
/**
* Constructs a dataset. By default, the dataset is assigned to its own
* group.
*/
protected AbstractDataset() {
this.group = new DatasetGroup();
this.listenerList = new EventListenerList();
}
/**
* Returns the dataset group for the dataset.
*
* @return The group (never <code>null</code>).
*
* @see #setGroup(DatasetGroup)
*/
public DatasetGroup getGroup() {
return this.group;
}
/**
* Sets the dataset group for the dataset.
*
* @param group the group (<code>null</code> not permitted).
*
* @see #getGroup()
*/
public void setGroup(DatasetGroup group) {
if (group == null) {
throw new IllegalArgumentException("Null 'group' argument.");
}
this.group = group;
}
/**
* Registers an object to receive notification of changes to the dataset.
*
* @param listener the object to register.
*
* @see #removeChangeListener(DatasetChangeListener)
*/
public void addChangeListener(DatasetChangeListener listener) {
this.listenerList.add(DatasetChangeListener.class, listener);
}
/**
* Deregisters an object so that it no longer receives notification of
* changes to the dataset.
*
* @param listener the object to deregister.
*
* @see #addChangeListener(DatasetChangeListener)
*/
public void removeChangeListener(DatasetChangeListener listener) {
this.listenerList.remove(DatasetChangeListener.class, listener);
}
/**
* Returns <code>true</code> if the specified object is registered with
* the dataset as a listener. Most applications won't need to call this
* method, it exists mainly for use by unit testing code.
*
* @param listener the listener.
*
* @return A boolean.
*
* @see #addChangeListener(DatasetChangeListener)
* @see #removeChangeListener(DatasetChangeListener)
*/
public boolean hasListener(EventListener listener) {
List list = Arrays.asList(this.listenerList.getListenerList());
return list.contains(listener);
}
/**
* Notifies all registered listeners that the dataset has changed.
*
* @see #addChangeListener(DatasetChangeListener)
*/
protected void fireDatasetChanged() {
notifyListeners(new DatasetChangeEvent(this, this));
}
/**
* Notifies all registered listeners that the dataset has changed.
*
* @param event contains information about the event that triggered the
* notification.
*
* @see #addChangeListener(DatasetChangeListener)
* @see #removeChangeListener(DatasetChangeListener)
*/
protected void notifyListeners(DatasetChangeEvent event) {
Object[] listeners = this.listenerList.getListenerList();
for (int i = listeners.length - 2; i >= 0; i -= 2) {
if (listeners[i] == DatasetChangeListener.class) {
((DatasetChangeListener) listeners[i + 1]).datasetChanged(
event);
}
}
}
/**
* Returns a clone of the dataset. The cloned dataset will NOT include the
* {@link DatasetChangeListener} references that have been registered with
* this dataset.
*
* @return A clone.
*
* @throws CloneNotSupportedException if the dataset does not support
* cloning.
*/
public Object clone() throws CloneNotSupportedException {
AbstractDataset clone = (AbstractDataset) super.clone();
clone.listenerList = new EventListenerList();
return clone;
}
/**
* Handles serialization.
*
* @param stream the output stream.
*
* @throws IOException if there is an I/O problem.
*/
private void writeObject(ObjectOutputStream stream) throws IOException {
stream.defaultWriteObject();
}
/**
* Restores a serialized object.
*
* @param stream the input stream.
*
* @throws IOException if there is an I/O problem.
* @throws ClassNotFoundException if there is a problem loading a class.
*/
private void readObject(ObjectInputStream stream)
throws IOException, ClassNotFoundException {
stream.defaultReadObject();
this.listenerList = new EventListenerList();
stream.registerValidation(this, 10); // see comments about priority of
// 10 in validateObject()
}
/**
* Validates the object. We use this opportunity to call listeners who have
* registered during the deserialization process, as listeners are not
* serialized. This method is called by the serialization system after the
* entire graph is read.
*
* This object has registered itself to the system with a priority of 10.
* Other callbacks may register with a higher priority number to be called
* before this object, or with a lower priority number to be called after
* the listeners were notified.
*
* All listeners are supposed to have register by now, either in their
* readObject or validateObject methods. Notify them that this dataset has
* changed.
*
* @exception InvalidObjectException If the object cannot validate itself.
*/
public void validateObject() throws InvalidObjectException {
fireDatasetChanged();
}
}
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