001 /* ===========================================================
002 * JFreeChart : a free chart 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/jfreechart/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 * RootHandler.java
029 * ----------------
030 * (C) Copyright 2003-2005, by Object Refinery Limited and Contributors.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): -;
034 *
035 * $Id: RootHandler.java,v 1.3.2.1 2005/10/25 21:36:10 mungady Exp $
036 *
037 * Changes
038 * -------
039 * 23-Jan-2003 : Version 1 (DG);
040 *
041 */
042
043 package org.jfree.data.xml;
044
045 import java.util.Stack;
046
047 import org.xml.sax.SAXException;
048 import org.xml.sax.helpers.DefaultHandler;
049
050 /**
051 * A SAX handler that delegates work to sub-handlers.
052 */
053 public class RootHandler extends DefaultHandler implements DatasetTags {
054
055 /** The sub-handlers. */
056 private Stack subHandlers;
057
058 /**
059 * Creates a new handler.
060 */
061 public RootHandler() {
062 this.subHandlers = new Stack();
063 }
064
065 /**
066 * Returns the stack of sub handlers.
067 *
068 * @return The sub-handler stack.
069 */
070 public Stack getSubHandlers() {
071 return this.subHandlers;
072 }
073
074 /**
075 * Receives some (or all) of the text in the current element.
076 *
077 * @param ch character buffer.
078 * @param start the start index.
079 * @param length the length of the valid character data.
080 *
081 * @throws SAXException for errors.
082 */
083 public void characters(char[] ch, int start, int length)
084 throws SAXException {
085 DefaultHandler handler = getCurrentHandler();
086 if (handler != this) {
087 handler.characters(ch, start, length);
088 }
089 }
090
091 /**
092 * Returns the handler at the top of the stack.
093 *
094 * @return The handler.
095 */
096 public DefaultHandler getCurrentHandler() {
097 DefaultHandler result = this;
098 if (this.subHandlers != null) {
099 if (this.subHandlers.size() > 0) {
100 Object top = this.subHandlers.peek();
101 if (top != null) {
102 result = (DefaultHandler) top;
103 }
104 }
105 }
106 return result;
107 }
108
109 /**
110 * Pushes a sub-handler onto the stack.
111 *
112 * @param subhandler the sub-handler.
113 */
114 public void pushSubHandler(DefaultHandler subhandler) {
115 this.subHandlers.push(subhandler);
116 }
117
118 /**
119 * Pops a sub-handler from the stack.
120 *
121 * @return The sub-handler.
122 */
123 public DefaultHandler popSubHandler() {
124 return (DefaultHandler) this.subHandlers.pop();
125 }
126
127 }