    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 * AbstractAnnotation.java
    029 * -----------------------
    030 * (C) Copyright 2009, by Object Refinery Limited and Contributors.
    031 *
    032 * Original Author:  Peter Kolb (see patch 2809117);
    033 * Contributor(s):   ;
    034 *
    035 * Changes:
    036 * --------
    037 * 20-Jun-2009 : Version 1 (PK);
    038 *
    039 */
    040
    041package org.jfree.chart.annotations;
    042
    043import java.io.IOException;
    044import java.io.ObjectInputStream;
    045import java.io.ObjectOutputStream;
    046import java.io.Serializable;
    047import java.util.Arrays;
    048import java.util.EventListener;
    049import java.util.List;
    050
    051import javax.swing.event.EventListenerList;
    052
    053import org.jfree.chart.event.AnnotationChangeEvent;
    054import org.jfree.chart.event.AnnotationChangeListener;
    055
    056/**
    057 * An abstract implementation of the {@link Annotation} interface, containing a
    058 * mechanism for registering change listeners.
    059 *
    060 * @since 1.0.14
    061 */
    062public abstract class AbstractAnnotation implements Annotation, Cloneable,
    063        Serializable {
    064
    065    /** Storage for registered change listeners. */
    066    private transient EventListenerList listenerList;
    067
    068    /**
    069     * A flag that indicates whether listeners should be notified
    070     * about changes of the annotation.
    071     */
    072    private boolean notify = true;
    073
    074    /**
    075     * Constructs an annotation.
    076     */
    077    protected AbstractAnnotation() {
    078        this.listenerList = new EventListenerList();
    079    }
    080
    081    /**
    082     * Registers an object to receive notification of changes to the
    083     * annotation.
    084     *
    085     * @param listener  the object to register.
    086     *
    087     * @see #removeChangeListener(AnnotationChangeListener)
    088     */
    089    public void addChangeListener(AnnotationChangeListener listener) {
    090        this.listenerList.add(AnnotationChangeListener.class, listener);
    091    }
    092
    093    /**
    094     * Deregisters an object so that it no longer receives notification of
    095     * changes to the annotation.
    096     *
    097     * @param listener  the object to deregister.
    098     *
    099     * @see #addChangeListener(AnnotationChangeListener)
    100     */
    101    public void removeChangeListener(AnnotationChangeListener listener) {
    102        this.listenerList.remove(AnnotationChangeListener.class, listener);
    103    }
    104
    105    /**
    106     * Returns <code>true</code> if the specified object is registered with
    107     * the annotation as a listener.  Most applications won't need to call this
    108     * method, it exists mainly for use by unit testing code.
    109     *
    110     * @param listener  the listener.
    111     *
    112     * @return A boolean.
    113     *
    114     * @see #addChangeListener(AnnotationChangeListener)
    115     * @see #removeChangeListener(AnnotationChangeListener)
    116     */
    117    public boolean hasListener(EventListener listener) {
    118        List list = Arrays.asList(this.listenerList.getListenerList());
    119        return list.contains(listener);
    120    }
    121
    122    /**
    123     * Notifies all registered listeners that the annotation has changed.
    124     *
    125     * @see #addChangeListener(AnnotationChangeListener)
    126     */
    127    protected void fireAnnotationChanged() {
    128        if (notify) {
    129            notifyListeners(new AnnotationChangeEvent(this, this));
    130        }
    131    }
    132
    133    /**
    134     * Notifies all registered listeners that the annotation has changed.
    135     *
    136     * @param event  contains information about the event that triggered the
    137     *               notification.
    138     *
    139     * @see #addChangeListener(AnnotationChangeListener)
    140     * @see #removeChangeListener(AnnotationChangeListener)
    141     */
    142    protected void notifyListeners(AnnotationChangeEvent event) {
    143
    144        Object[] listeners = this.listenerList.getListenerList();
    145        for (int i = listeners.length - 2; i >= 0; i -= 2) {
    146            if (listeners[i] == AnnotationChangeListener.class) {
    147                ((AnnotationChangeListener) listeners[i + 1]).annotationChanged(
    148                        event);
    149            }
    150        }
    151
    152    }
    153
    154    /**
    155     * Returns a flag that indicates whether listeners should be
    156     * notified about changes to the annotation.
    157     *
    158     * @return  the flag.
    159     *
    160     * @see #setNotify(boolean)
    161     */
    162    public boolean getNotify(){
    163        return this.notify;
    164    }
    165
    166    /**
    167     * Sets a flag that indicates whether listeners should be notified about
    168     * changes of an annotation.
    169     *
    170     * @param flag  the flag
    171     *
    172     * @see #getNotify()
    173     */
    174    public void setNotify(boolean flag){
    175        this.notify = flag;
    176        if (notify) {
    177            fireAnnotationChanged();
    178        }
    179    }
    180
    181    /**
    182     * Returns a clone of the annotation. The cloned annotation will NOT
    183     * include the {@link AnnotationChangeListener} references that have been
    184     * registered with this annotation.
    185     *
    186     * @return A clone.
    187     *
    188     * @throws CloneNotSupportedException  if the annotation does not support
    189     *                                     cloning.
    190     */
    191    public Object clone() throws CloneNotSupportedException {
    192        AbstractAnnotation clone = (AbstractAnnotation) super.clone();
    193        clone.listenerList = new EventListenerList();
    194        return clone;
    195    }
    196
    197    /**
    198     * Handles serialization.
    199     *
    200     * @param stream  the output stream.
    201     *
    202     * @throws IOException if there is an I/O problem.
    203     */
    204    private void writeObject(ObjectOutputStream stream) throws IOException {
    205        stream.defaultWriteObject();
    206    }
    207
    208    /**
    209     * Restores a serialized object.
    210     *
    211     * @param stream  the input stream.
    212     *
    213     * @throws IOException if there is an I/O problem.
    214     * @throws ClassNotFoundException if there is a problem loading a class.
    215     */
    216    private void readObject(ObjectInputStream stream)
    217        throws IOException, ClassNotFoundException {
    218        stream.defaultReadObject();
    219        this.listenerList = new EventListenerList();
    220    }
    221
    222}