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Java > Open Source Codes > org > jfree > xml > parser > coretypes > GradientPaintReadHandler


1 /* ========================================================================
2  * JCommon : a free general purpose class library for the Java(tm) platform
3  * ========================================================================
4  *
5  * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
6  *
7  * Project Info: http://www.jfree.org/jcommon/index.html
8  *
9  * This library is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU Lesser General Public License as published by
11  * the Free Software Foundation; either version 2.1 of the License, or
12  * (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17  * License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with this library; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
22  * USA.
23  *
24  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25  * in the United States and other countries.]
26  *
27  * ------------------------
28  * GradientPaintReadHandler
29  * ------------------------
30  * (C) Copyright 2003, by Thomas Morgner and Contributors.
31  *
32  * Original Author: Thomas Morgner;
33  * Contributor(s): David Gilbert (for Object Refinery Limited);
34  *
35  * $Id: GradientPaintReadHandler.java,v 1.2 2005/10/18 13:33:32 mungady Exp $
36  *
37  * Changes (from 25-Nov-2003)
38  * --------------------------
39  * 25-Nov-2003 : Added standard header and Javadocs (DG);
40  *
41  */
42
43 package org.jfree.xml.parser.coretypes;
44
45 import java.awt.Color JavaDoc;
46 import java.awt.GradientPaint JavaDoc;
47 import java.awt.geom.Point2D JavaDoc;
48
49 import org.jfree.xml.parser.AbstractXmlReadHandler;
50 import org.jfree.xml.parser.XmlReadHandler;
51 import org.jfree.xml.parser.XmlReaderException;
52 import org.xml.sax.Attributes JavaDoc;
53 import org.xml.sax.SAXException JavaDoc;
54
55 /**
56  * A SAX handler for reading a {@link GradientPaint} from an XML element.
57  */
58 public class GradientPaintReadHandler extends AbstractXmlReadHandler {
59
60     /** The gradient paint under construction. */
61     private GradientPaint JavaDoc gradient;
62
63     /** The handler for color 1. */
64     private XmlReadHandler color1Handler;
65
66     /** The handler for color 2. */
67     private XmlReadHandler color2Handler;
68
69     /** The handler for point 1. */
70     private XmlReadHandler point1Handler;
71
72     /** The handler for point 2. */
73     private XmlReadHandler point2Handler;
74
75     /**
76      * Creates a new handler.
77      */
78     public GradientPaintReadHandler() {
79         super();
80     }
81
82     /**
83      * Returns the gradient paint under construction.
84      *
85      * @return the gradient paint.
86      */
87     public Object JavaDoc getObject() {
88         return this.gradient;
89     }
90
91     /**
92      * Returns the handler for a child element.
93      *
94      * @param tagName the tag name.
95      * @param atts the attributes.
96      *
97      * @return the handler.
98      * @throws SAXException to indicate a parsing error.
99      * @throws XmlReaderException if there is a reader error.
100      */
101     protected XmlReadHandler getHandlerForChild(final String JavaDoc tagName, final Attributes JavaDoc atts)
102         throws SAXException JavaDoc, XmlReaderException {
103         if ("color1".equals(tagName)) {
104             this.color1Handler = getRootHandler().createHandler(Color JavaDoc.class, tagName, atts);
105             return this.color1Handler;
106         }
107         else if ("color2".equals(tagName)) {
108             this.color2Handler = getRootHandler().createHandler(Color JavaDoc.class, tagName, atts);
109             return this.color2Handler;
110         }
111         else if ("point1".equals(tagName)) {
112             this.point1Handler = getRootHandler().createHandler(Point2D JavaDoc.class, tagName, atts);
113             return this.point1Handler;
114         }
115         else if ("point2".equals(tagName)) {
116             this.point2Handler = getRootHandler().createHandler(Point2D JavaDoc.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 JavaDoc
133             ((Point2D JavaDoc) this.point1Handler.getObject(),
134             (Color JavaDoc) this.color1Handler.getObject(),
135             (Point2D JavaDoc) this.point2Handler.getObject(),
136             (Color JavaDoc) this.color2Handler.getObject());
137     }
138
139 }
140
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