/* ===========================================================
* JFreeChart : a free chart library for the Java(tm) platform
* ===========================================================
*
* (C) Copyright 2000-2012, 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.]
*
* ----------------------
* AbstractDialLayer.java
* ----------------------
* (C) Copyright 2006-2008, by Object Refinery Limited.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): -;
*
* Changes
* -------
* 06-Nov-2006 : Version 1 (DG);
* 17-Nov-2006 : Added visible flag (DG);
* 16-Oct-2007 : Implemented equals() and clone() (DG);
*
*/
package org.jfree.chart.plot.dial;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.Arrays;
import java.util.EventListener;
import java.util.List;
import javax.swing.event.EventListenerList;
import org.jfree.chart.util.HashUtils;
/**
* A base class that can be used to implement a {@link DialLayer}. It includes
* an event notification mechanism.
*
* @since 1.0.7
*/
public abstract class AbstractDialLayer implements DialLayer {
/** A flag that controls whether or not the layer is visible. */
private boolean visible;
/** Storage for registered listeners. */
private transient EventListenerList listenerList;
/**
* Creates a new instance.
*/
protected AbstractDialLayer() {
this.visible = true;
this.listenerList = new EventListenerList();
}
/**
* Returns <code>true</code> if this layer is visible (should be displayed),
* and <code>false</code> otherwise.
*
* @return A boolean.
*
* @see #setVisible(boolean)
*/
@Override
public boolean isVisible() {
return this.visible;
}
/**
* Sets the flag that determines whether or not this layer is drawn by
* the plot, and sends a {@link DialLayerChangeEvent} to all registered
* listeners.
*
* @param visible the flag.
*
* @see #isVisible()
*/
public void setVisible(boolean visible) {
this.visible = visible;
notifyListeners(new DialLayerChangeEvent(this));
}
/**
* Tests this instance for equality with an arbitrary object.
*
* @param obj the object (<code>null</code> permitted).
*
* @return A boolean.
*/
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof AbstractDialLayer)) {
return false;
}
AbstractDialLayer that = (AbstractDialLayer) obj;
return this.visible == that.visible;
}
/**
* Returns a hash code for this instance.
*
* @return A hash code.
*/
@Override
public int hashCode() {
int result = 23;
result = HashUtils.hashCode(result, this.visible);
return result;
}
/**
* Returns a clone of this instance.
*
* @return A clone.
*
* @throws CloneNotSupportedException if there is a problem cloning this
* instance.
*/
@Override
public Object clone() throws CloneNotSupportedException {
AbstractDialLayer clone = (AbstractDialLayer) super.clone();
// we don't clone the listeners
clone.listenerList = new EventListenerList();
return clone;
}
/**
* Registers an object for notification of changes to the dial layer.
*
* @param listener the object that is being registered.
*
* @see #removeChangeListener(DialLayerChangeListener)
*/
@Override
public void addChangeListener(DialLayerChangeListener listener) {
this.listenerList.add(DialLayerChangeListener.class, listener);
}
/**
* Deregisters an object for notification of changes to the dial layer.
*
* @param listener the object to deregister.
*
* @see #addChangeListener(DialLayerChangeListener)
*/
@Override
public void removeChangeListener(DialLayerChangeListener listener) {
this.listenerList.remove(DialLayerChangeListener.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.
*/
@Override
public boolean hasListener(EventListener listener) {
List<Object> list = Arrays.asList(this.listenerList.getListenerList());
return list.contains(listener);
}
/**
* Notifies all registered listeners that the dial layer has changed.
* The {@link DialLayerChangeEvent} provides information about the change.
*
* @param event information about the change to the axis.
*/
protected void notifyListeners(DialLayerChangeEvent event) {
Object[] listeners = this.listenerList.getListenerList();
for (int i = listeners.length - 2; i >= 0; i -= 2) {
if (listeners[i] == DialLayerChangeListener.class) {
((DialLayerChangeListener) listeners[i + 1]).dialLayerChanged(
event);
}
}
}
/**
* Provides serialization support.
*
* @param stream the input stream.
*
* @throws IOException if there is an I/O error.
* @throws ClassNotFoundException if there is a classpath problem.
*/
private void readObject(ObjectInputStream stream)
throws IOException, ClassNotFoundException {
stream.defaultReadObject();
this.listenerList = new EventListenerList();
}
}