001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2008, 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 2003-2008, by Object Refinery Limited and Contributors.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): -;
034 *
035 * Changes
036 * -------
037 * 23-Jan-2003 : Version 1 (DG);
038 *
039 */
040
041 package org.jfree.data.xml;
042
043 import java.util.Stack;
044
045 import org.xml.sax.SAXException;
046 import org.xml.sax.helpers.DefaultHandler;
047
048 /**
049 * A SAX handler that delegates work to sub-handlers.
050 */
051 public class RootHandler extends DefaultHandler implements DatasetTags {
052
053 /** The sub-handlers. */
054 private Stack subHandlers;
055
056 /**
057 * Creates a new handler.
058 */
059 public RootHandler() {
060 this.subHandlers = new Stack();
061 }
062
063 /**
064 * Returns the stack of sub handlers.
065 *
066 * @return The sub-handler stack.
067 */
068 public Stack getSubHandlers() {
069 return this.subHandlers;
070 }
071
072 /**
073 * Receives some (or all) of the text in the current element.
074 *
075 * @param ch character buffer.
076 * @param start the start index.
077 * @param length the length of the valid character data.
078 *
079 * @throws SAXException for errors.
080 */
081 public void characters(char[] ch, int start, int length)
082 throws SAXException {
083 DefaultHandler handler = getCurrentHandler();
084 if (handler != this) {
085 handler.characters(ch, start, length);
086 }
087 }
088
089 /**
090 * Returns the handler at the top of the stack.
091 *
092 * @return The handler.
093 */
094 public DefaultHandler getCurrentHandler() {
095 DefaultHandler result = this;
096 if (this.subHandlers != null) {
097 if (this.subHandlers.size() > 0) {
098 Object top = this.subHandlers.peek();
099 if (top != null) {
100 result = (DefaultHandler) top;
101 }
102 }
103 }
104 return result;
105 }
106
107 /**
108 * Pushes a sub-handler onto the stack.
109 *
110 * @param subhandler the sub-handler.
111 */
112 public void pushSubHandler(DefaultHandler subhandler) {
113 this.subHandlers.push(subhandler);
114 }
115
116 /**
117 * Pops a sub-handler from the stack.
118 *
119 * @return The sub-handler.
120 */
121 public DefaultHandler popSubHandler() {
122 return (DefaultHandler) this.subHandlers.pop();
123 }
124
125 }