001/* ========================================================================
002 * JCommon : a free general purpose class library for the Java(tm) platform
003 * ========================================================================
004 *
005 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006 * 
007 * Project Info:  http://www.jfree.org/jcommon/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 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
025 * in the United States and other countries.]
026 * 
027 * ------------------------
028 * GradientPaintReadHandler
029 * ------------------------
030 * (C) Copyright 2003, by Thomas Morgner and Contributors.
031 *
032 * Original Author:  Thomas Morgner;
033 * Contributor(s):   David Gilbert (for Object Refinery Limited);
034 *
035 * $Id: GradientPaintReadHandler.java,v 1.2 2005/10/18 13:33:32 mungady Exp $
036 *
037 * Changes (from 25-Nov-2003)
038 * --------------------------
039 * 25-Nov-2003 : Added standard header and Javadocs (DG);
040 *
041 */
042
043package org.jfree.xml.parser.coretypes;
044
045import java.awt.Color;
046import java.awt.GradientPaint;
047import java.awt.geom.Point2D;
048
049import org.jfree.xml.parser.AbstractXmlReadHandler;
050import org.jfree.xml.parser.XmlReadHandler;
051import org.jfree.xml.parser.XmlReaderException;
052import org.xml.sax.Attributes;
053import org.xml.sax.SAXException;
054
055/**
056 * A SAX handler for reading a {@link GradientPaint} from an XML element.
057 */
058public class GradientPaintReadHandler extends AbstractXmlReadHandler  {
059
060    /** The gradient paint under construction. */
061    private GradientPaint gradient;
062
063    /** The handler for color 1. */
064    private XmlReadHandler color1Handler;
065
066    /** The handler for color 2. */
067    private XmlReadHandler color2Handler;
068
069    /** The handler for point 1. */
070    private XmlReadHandler point1Handler;
071
072    /** The handler for point 2. */
073    private XmlReadHandler point2Handler;
074
075    /**
076     * Creates a new handler.
077     */
078    public GradientPaintReadHandler() {
079        super();
080    }
081
082    /**
083     * Returns the gradient paint under construction.
084     * 
085     * @return the gradient paint.
086     */
087    public Object getObject() {
088        return this.gradient;
089    }
090
091    /**
092     * Returns the handler for a child element.
093     * 
094     * @param tagName  the tag name.
095     * @param atts  the attributes.
096     * 
097     * @return the handler.
098     * @throws SAXException to indicate a parsing error.
099     * @throws XmlReaderException if there is a reader error.
100     */
101    protected XmlReadHandler getHandlerForChild(final String tagName, final Attributes atts)
102        throws SAXException, XmlReaderException {
103        if ("color1".equals(tagName)) {
104            this.color1Handler = getRootHandler().createHandler(Color.class, tagName, atts);
105            return this.color1Handler;
106        }
107        else if ("color2".equals(tagName)) {
108            this.color2Handler = getRootHandler().createHandler(Color.class, tagName, atts);
109            return this.color2Handler;
110        }
111        else if ("point1".equals(tagName)) {
112            this.point1Handler = getRootHandler().createHandler(Point2D.class, tagName, atts);
113            return this.point1Handler;
114        }
115        else if ("point2".equals(tagName)) {
116            this.point2Handler = getRootHandler().createHandler(Point2D.class, tagName, atts);
117            return this.point2Handler;
118        }
119        return null;
120    }
121
122    /**
123     * At the end of parsing the element, the gradient paint is constructed.
124     * 
125     * @throws XmlReaderException if there is a parsing error.
126     */
127    protected void doneParsing() throws XmlReaderException {
128        if (this.point1Handler == null || this.point2Handler == null 
129            || this.color1Handler == null || this.color2Handler == null) {
130            throw new XmlReaderException("Not all required subelements are defined.");
131        }
132        this.gradient = new GradientPaint
133            ((Point2D) this.point1Handler.getObject(),
134            (Color) this.color1Handler.getObject(),
135            (Point2D) this.point2Handler.getObject(),
136            (Color) this.color2Handler.getObject());
137    }
138
139}