jfreechart example source code file (Title.java)

This example jfreechart source code file (Title.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - jfreechart tags/keywords

awt, event, eventlistenerlist, geometry, gui, horizontalalignment, illegalargumentexception, illegalargumentexception, io, null, null, object, rectangleedge, rectangleinsets, swing, title, title, titlechangeevent, verticalalignment, verticalalignment

The jfreechart Title.java source code

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, 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.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * ----------
 * Title.java
 * ----------
 * (C) Copyright 2000-2008, by David Berry and Contributors.
 *
 * Original Author:  David Berry;
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *                   Nicolas Brodu;
 *
 * Changes (from 21-Aug-2001)
 * --------------------------
 * 21-Aug-2001 : Added standard header (DG);
 * 18-Sep-2001 : Updated header (DG);
 * 14-Nov-2001 : Package com.jrefinery.common.ui.* changed to
 *               com.jrefinery.ui.* (DG);
 * 07-Feb-2002 : Changed blank space around title from Insets --> Spacer, to
 *               allow for relative or absolute spacing (DG);
 * 25-Jun-2002 : Removed unnecessary imports (DG);
 * 01-Oct-2002 : Fixed errors reported by Checkstyle (DG);
 * 14-Oct-2002 : Changed the event listener storage structure (DG);
 * 11-Sep-2003 : Took care of listeners while cloning (NB);
 * 22-Sep-2003 : Spacer cannot be null. Added nullpointer checks for this (TM);
 * 08-Jan-2003 : Renamed AbstractTitle --> Title and moved to separate
 *               package (DG);
 * 26-Oct-2004 : Refactored to implement Block interface, and removed redundant
 *               constants (DG);
 * 11-Jan-2005 : Removed deprecated code in preparation for the 1.0.0
 *               release (DG);
 * 02-Feb-2005 : Changed Spacer --> RectangleInsets for padding (DG);
 * 03-May-2005 : Fixed problem in equals() method (DG);
 * 19-Sep-2008 : Added visibility flag (DG);
 *
 */

package org.jfree.chart.title;

import java.awt.Graphics2D;
import java.awt.geom.Rectangle2D;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

import javax.swing.event.EventListenerList;

import org.jfree.chart.block.AbstractBlock;
import org.jfree.chart.block.Block;
import org.jfree.chart.event.TitleChangeEvent;
import org.jfree.chart.event.TitleChangeListener;
import org.jfree.ui.HorizontalAlignment;
import org.jfree.ui.RectangleEdge;
import org.jfree.ui.RectangleInsets;
import org.jfree.ui.VerticalAlignment;
import org.jfree.util.ObjectUtilities;

/**
 * The base class for all chart titles.  A chart can have multiple titles,
 * appearing at the top, bottom, left or right of the chart.
 * <P>
 * Concrete implementations of this class will render text and images, and
 * hence do the actual work of drawing titles.
 */
public abstract class Title extends AbstractBlock
            implements Block, Cloneable, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = -6675162505277817221L;

    /** The default title position. */
    public static final RectangleEdge DEFAULT_POSITION = RectangleEdge.TOP;

    /** The default horizontal alignment. */
    public static final HorizontalAlignment
            DEFAULT_HORIZONTAL_ALIGNMENT = HorizontalAlignment.CENTER;

    /** The default vertical alignment. */
    public static final VerticalAlignment
            DEFAULT_VERTICAL_ALIGNMENT = VerticalAlignment.CENTER;

    /** Default title padding. */
    public static final RectangleInsets DEFAULT_PADDING = new RectangleInsets(
            1, 1, 1, 1);

    /**
     * A flag that controls whether or not the title is visible.
     *
     * @since 1.0.11
     */
    public boolean visible;

    /** The title position. */
    private RectangleEdge position;

    /** The horizontal alignment of the title content. */
    private HorizontalAlignment horizontalAlignment;

    /** The vertical alignment of the title content. */
    private VerticalAlignment verticalAlignment;

    /** Storage for registered change listeners. */
    private transient EventListenerList listenerList;

    /**
     * A flag that can be used to temporarily disable the listener mechanism.
     */
    private boolean notify;

    /**
     * Creates a new title, using default attributes where necessary.
     */
    protected Title() {
        this(Title.DEFAULT_POSITION,
                Title.DEFAULT_HORIZONTAL_ALIGNMENT,
                Title.DEFAULT_VERTICAL_ALIGNMENT, Title.DEFAULT_PADDING);
    }

    /**
     * Creates a new title, using default attributes where necessary.
     *
     * @param position  the position of the title (<code>null not
     *                  permitted).
     * @param horizontalAlignment  the horizontal alignment of the title
     *                             (<code>null not permitted).
     * @param verticalAlignment  the vertical alignment of the title
     *                           (<code>null not permitted).
     */
    protected Title(RectangleEdge position,
                    HorizontalAlignment horizontalAlignment,
                    VerticalAlignment verticalAlignment) {

        this(position, horizontalAlignment, verticalAlignment,
                Title.DEFAULT_PADDING);

    }

    /**
     * Creates a new title.
     *
     * @param position  the position of the title (<code>null not
     *                  permitted).
     * @param horizontalAlignment  the horizontal alignment of the title (LEFT,
     *                             CENTER or RIGHT, <code>null not
     *                             permitted).
     * @param verticalAlignment  the vertical alignment of the title (TOP,
     *                           MIDDLE or BOTTOM, <code>null not
     *                           permitted).
     * @param padding  the amount of space to leave around the outside of the
     *                 title (<code>null not permitted).
     */
    protected Title(RectangleEdge position,
                    HorizontalAlignment horizontalAlignment,
                    VerticalAlignment verticalAlignment,
                    RectangleInsets padding) {

        // check arguments...
        if (position == null) {
            throw new IllegalArgumentException("Null 'position' argument.");
        }
        if (horizontalAlignment == null) {
            throw new IllegalArgumentException(
                    "Null 'horizontalAlignment' argument.");
        }

        if (verticalAlignment == null) {
            throw new IllegalArgumentException(
                    "Null 'verticalAlignment' argument.");
        }
        if (padding == null) {
            throw new IllegalArgumentException("Null 'spacer' argument.");
        }

        this.visible = true;
        this.position = position;
        this.horizontalAlignment = horizontalAlignment;
        this.verticalAlignment = verticalAlignment;
        setPadding(padding);
        this.listenerList = new EventListenerList();
        this.notify = true;

    }

    /**
     * Returns a flag that controls whether or not the title should be
     * drawn.  The default value is <code>true.
     *
     * @return A boolean.
     *
     * @see #setVisible(boolean)
     *
     * @since 1.0.11
     */
    public boolean isVisible() {
        return this.visible;
    }

    /**
     * Sets a flag that controls whether or not the title should be drawn, and
     * sends a {@link TitleChangeEvent} to all registered listeners.
     *
     * @param visible  the new flag value.
     *
     * @see #isVisible()
     *
     * @since 1.0.11
     */
    public void setVisible(boolean visible) {
        this.visible = visible;
        notifyListeners(new TitleChangeEvent(this));
    }

    /**
     * Returns the position of the title.
     *
     * @return The title position (never <code>null).
     */
    public RectangleEdge getPosition() {
        return this.position;
    }

    /**
     * Sets the position for the title and sends a {@link TitleChangeEvent} to
     * all registered listeners.
     *
     * @param position  the position (<code>null not permitted).
     */
    public void setPosition(RectangleEdge position) {
        if (position == null) {
            throw new IllegalArgumentException("Null 'position' argument.");
        }
        if (this.position != position) {
            this.position = position;
            notifyListeners(new TitleChangeEvent(this));
        }
    }

    /**
     * Returns the horizontal alignment of the title.
     *
     * @return The horizontal alignment (never <code>null).
     */
    public HorizontalAlignment getHorizontalAlignment() {
        return this.horizontalAlignment;
    }

    /**
     * Sets the horizontal alignment for the title and sends a
     * {@link TitleChangeEvent} to all registered listeners.
     *
     * @param alignment  the horizontal alignment (<code>null not
     *                   permitted).
     */
    public void setHorizontalAlignment(HorizontalAlignment alignment) {
        if (alignment == null) {
            throw new IllegalArgumentException("Null 'alignment' argument.");
        }
        if (this.horizontalAlignment != alignment) {
            this.horizontalAlignment = alignment;
            notifyListeners(new TitleChangeEvent(this));
        }
    }

    /**
     * Returns the vertical alignment of the title.
     *
     * @return The vertical alignment (never <code>null).
     */
    public VerticalAlignment getVerticalAlignment() {
        return this.verticalAlignment;
    }

    /**
     * Sets the vertical alignment for the title, and notifies any registered
     * listeners of the change.
     *
     * @param alignment  the new vertical alignment (TOP, MIDDLE or BOTTOM,
     *                   <code>null not permitted).
     */
    public void setVerticalAlignment(VerticalAlignment alignment) {
        if (alignment == null) {
            throw new IllegalArgumentException("Null 'alignment' argument.");
        }
        if (this.verticalAlignment != alignment) {
            this.verticalAlignment = alignment;
            notifyListeners(new TitleChangeEvent(this));
        }
    }

    /**
     * Returns the flag that indicates whether or not the notification
     * mechanism is enabled.
     *
     * @return The flag.
     */
    public boolean getNotify() {
        return this.notify;
    }

    /**
     * Sets the flag that indicates whether or not the notification mechanism
     * is enabled.  There are certain situations (such as cloning) where you
     * want to turn notification off temporarily.
     *
     * @param flag  the new value of the flag.
     */
    public void setNotify(boolean flag) {
        this.notify = flag;
        if (flag) {
            notifyListeners(new TitleChangeEvent(this));
        }
    }

    /**
     * Draws the title on a Java 2D graphics device (such as the screen or a
     * printer).
     *
     * @param g2  the graphics device.
     * @param area  the area allocated for the title (subclasses should not
     *              draw outside this area).
     */
    public abstract void draw(Graphics2D g2, Rectangle2D area);

    /**
     * Returns a clone of the title.
     * <P>
     * One situation when this is useful is when editing the title properties -
     * you can edit a clone, and then it is easier to cancel the changes if
     * necessary.
     *
     * @return A clone of the title.
     *
     * @throws CloneNotSupportedException not thrown by this class, but it may
     *         be thrown by subclasses.
     */
    public Object clone() throws CloneNotSupportedException {
        Title duplicate = (Title) super.clone();
        duplicate.listenerList = new EventListenerList();
        // RectangleInsets is immutable => same reference in clone OK
        return duplicate;
    }

    /**
     * Registers an object for notification of changes to the title.
     *
     * @param listener  the object that is being registered.
     */
    public void addChangeListener(TitleChangeListener listener) {
        this.listenerList.add(TitleChangeListener.class, listener);
    }

    /**
     * Unregisters an object for notification of changes to the chart title.
     *
     * @param listener  the object that is being unregistered.
     */
    public void removeChangeListener(TitleChangeListener listener) {
        this.listenerList.remove(TitleChangeListener.class, listener);
    }

    /**
     * Notifies all registered listeners that the chart title has changed in
     * some way.
     *
     * @param event  an object that contains information about the change to
     *               the title.
     */
    protected void notifyListeners(TitleChangeEvent event) {
        if (this.notify) {
            Object[] listeners = this.listenerList.getListenerList();
            for (int i = listeners.length - 2; i >= 0; i -= 2) {
                if (listeners[i] == TitleChangeListener.class) {
                    ((TitleChangeListener) listeners[i + 1]).titleChanged(
                            event);
                }
            }
        }
    }

    /**
     * Tests an object for equality with this title.
     *
     * @param obj  the object (<code>null not permitted).
     *
     * @return <code>true or false.
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof Title)) {
            return false;
        }
        Title that = (Title) obj;
        if (this.visible != that.visible) {
            return false;
        }
        if (this.position != that.position) {
            return false;
        }
        if (this.horizontalAlignment != that.horizontalAlignment) {
            return false;
        }
        if (this.verticalAlignment != that.verticalAlignment) {
            return false;
        }
        if (this.notify != that.notify) {
            return false;
        }
        return super.equals(obj);
    }

    /**
     * Returns a hashcode for the title.
     *
     * @return The hashcode.
     */
    public int hashCode() {
        int result = 193;
        result = 37 * result + ObjectUtilities.hashCode(this.position);
        result = 37 * result
                + ObjectUtilities.hashCode(this.horizontalAlignment);
        result = 37 * result + ObjectUtilities.hashCode(this.verticalAlignment);
        return result;
    }

    /**
     * Provides serialization support.
     *
     * @param stream  the output stream.
     *
     * @throws IOException  if there is an I/O error.
     */
    private void writeObject(ObjectOutputStream stream) throws IOException {
        stream.defaultWriteObject();
    }

    /**
     * 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();
    }

}