Java tutorial
/* =========================================================== * JFreeChart : a free chart library for the Java(tm) platform * =========================================================== * * (C) Copyright 2000-2013, 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.] * * ---------- * Title.java * ---------- * (C) Copyright 2000-2013, 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); * 02-Jul-2013 : Use ParamChecks (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.chart.util.ParamChecks; 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</code> not * permitted). * @param horizontalAlignment the horizontal alignment of the title * (<code>null</code> not permitted). * @param verticalAlignment the vertical alignment of the title * (<code>null</code> 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</code> not * permitted). * @param horizontalAlignment the horizontal alignment of the title (LEFT, * CENTER or RIGHT, <code>null</code> not * permitted). * @param verticalAlignment the vertical alignment of the title (TOP, * MIDDLE or BOTTOM, <code>null</code> not * permitted). * @param padding the amount of space to leave around the outside of the * title (<code>null</code> not permitted). */ protected Title(RectangleEdge position, HorizontalAlignment horizontalAlignment, VerticalAlignment verticalAlignment, RectangleInsets padding) { ParamChecks.nullNotPermitted(position, "position"); ParamChecks.nullNotPermitted(horizontalAlignment, "horizontalAlignment"); ParamChecks.nullNotPermitted(verticalAlignment, "verticalAlignment"); ParamChecks.nullNotPermitted(padding, "padding"); 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</code>. * * @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</code>). */ 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</code> not permitted). */ public void setPosition(RectangleEdge position) { ParamChecks.nullNotPermitted(position, "position"); 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</code>). */ 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</code> not * permitted). */ public void setHorizontalAlignment(HorizontalAlignment alignment) { ParamChecks.nullNotPermitted(alignment, "alignment"); 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</code>). */ 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</code> not permitted). */ public void setVerticalAlignment(VerticalAlignment alignment) { ParamChecks.nullNotPermitted(alignment, "alignment"); 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). */ @Override 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. */ @Override 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</code> not permitted). * * @return <code>true</code> or <code>false</code>. */ @Override 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. */ @Override 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(); } }