Java tutorial
/* =========================================================== * JFreeChart : a free chart library for the Java(tm) platform * =========================================================== * * (C) Copyright 2000-2014, 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.] * * ------------- * PaintMap.java * ------------- * (C) Copyright 2006-2014, by Object Refinery Limited. * * Original Author: David Gilbert (for Object Refinery Limited); * Contributor(s): -; * * Changes: * -------- * 27-Sep-2006 : Version 1 (DG); * 17-Jan-2007 : Changed TreeMap to HashMap, so that different classes that * implement Comparable can be used as keys (DG); * 02-Jul-2013 : Use ParamChecks class (DG); * */ package org.jfree.chart; import java.awt.Paint; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.Serializable; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.Set; import org.jfree.chart.util.ParamChecks; import org.jfree.io.SerialUtilities; import org.jfree.util.PaintUtilities; /** * A storage structure that maps <code>Comparable</code> instances with * <code>Paint</code> instances. * <br><br> * To support cloning and serialization, you should only use keys that are * cloneable and serializable. Special handling for the <code>Paint</code> * instances is included in this class. * * @since 1.0.3 */ public class PaintMap implements Cloneable, Serializable { /** For serialization. */ static final long serialVersionUID = -4639833772123069274L; /** Storage for the keys and values. */ private transient Map store; /** * Creates a new (empty) map. */ public PaintMap() { this.store = new HashMap(); } /** * Returns the paint associated with the specified key, or * <code>null</code>. * * @param key the key (<code>null</code> not permitted). * * @return The paint, or <code>null</code>. * * @throws IllegalArgumentException if <code>key</code> is * <code>null</code>. */ public Paint getPaint(Comparable key) { ParamChecks.nullNotPermitted(key, "key"); return (Paint) this.store.get(key); } /** * Returns <code>true</code> if the map contains the specified key, and * <code>false</code> otherwise. * * @param key the key. * * @return <code>true</code> if the map contains the specified key, and * <code>false</code> otherwise. */ public boolean containsKey(Comparable key) { return this.store.containsKey(key); } /** * Adds a mapping between the specified <code>key</code> and * <code>paint</code> values. * * @param key the key (<code>null</code> not permitted). * @param paint the paint. * * @throws IllegalArgumentException if <code>key</code> is * <code>null</code>. */ public void put(Comparable key, Paint paint) { ParamChecks.nullNotPermitted(key, "key"); this.store.put(key, paint); } /** * Resets the map to empty. */ public void clear() { this.store.clear(); } /** * Tests this map 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 PaintMap)) { return false; } PaintMap that = (PaintMap) obj; if (this.store.size() != that.store.size()) { return false; } Set keys = this.store.keySet(); Iterator iterator = keys.iterator(); while (iterator.hasNext()) { Comparable key = (Comparable) iterator.next(); Paint p1 = getPaint(key); Paint p2 = that.getPaint(key); if (!PaintUtilities.equal(p1, p2)) { return false; } } return true; } /** * Returns a clone of this <code>PaintMap</code>. * * @return A clone of this instance. * * @throws CloneNotSupportedException if any key is not cloneable. */ @Override public Object clone() throws CloneNotSupportedException { PaintMap clone = (PaintMap) super.clone(); clone.store = new HashMap(); clone.store.putAll(this.store); // TODO: I think we need to make sure the keys are actually cloned, // whereas the paint instances are always immutable so they're OK return clone; } /** * 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(); stream.writeInt(this.store.size()); Set keys = this.store.keySet(); Iterator iterator = keys.iterator(); while (iterator.hasNext()) { Comparable key = (Comparable) iterator.next(); stream.writeObject(key); Paint paint = getPaint(key); SerialUtilities.writePaint(paint, stream); } } /** * 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.store = new HashMap(); int keyCount = stream.readInt(); for (int i = 0; i < keyCount; i++) { Comparable key = (Comparable) stream.readObject(); Paint paint = SerialUtilities.readPaint(stream); this.store.put(key, paint); } } }