Source for org.jfree.data.xml.RootHandler

   1: /* ===========================================================
   2:  * JFreeChart : a free chart 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/jfreechart/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:  * RootHandler.java
  29:  * ----------------
  30:  * (C) Copyright 2003-2005, by Object Refinery Limited and Contributors.
  31:  *
  32:  * Original Author:  David Gilbert (for Object Refinery Limited);
  33:  * Contributor(s):   -;
  34:  *
  35:  * $Id: RootHandler.java,v 1.3.2.1 2005/10/25 21:36:10 mungady Exp $
  36:  *
  37:  * Changes
  38:  * -------
  39:  * 23-Jan-2003 : Version 1 (DG);
  40:  *
  41:  */
  42: 
  43: package org.jfree.data.xml;
  44: 
  45: import java.util.Stack;
  46: 
  47: import org.xml.sax.SAXException;
  48: import org.xml.sax.helpers.DefaultHandler;
  49: 
  50: /**
  51:  * A SAX handler that delegates work to sub-handlers.
  52:  */
  53: public class RootHandler extends DefaultHandler implements DatasetTags {
  54: 
  55:     /** The sub-handlers. */
  56:     private Stack subHandlers;
  57: 
  58:     /**
  59:      * Creates a new handler.
  60:      */
  61:     public RootHandler() {
  62:         this.subHandlers = new Stack();
  63:     }
  64: 
  65:     /**
  66:      * Returns the stack of sub handlers.
  67:      *
  68:      * @return The sub-handler stack.
  69:      */
  70:     public Stack getSubHandlers() {
  71:         return this.subHandlers;
  72:     }
  73: 
  74:     /**
  75:      * Receives some (or all) of the text in the current element.
  76:      *
  77:      * @param ch  character buffer.
  78:      * @param start  the start index.
  79:      * @param length  the length of the valid character data.
  80:      *
  81:      * @throws SAXException for errors.
  82:      */
  83:     public void characters(char[] ch, int start, int length) 
  84:         throws SAXException {
  85:         DefaultHandler handler = getCurrentHandler();
  86:         if (handler != this) {
  87:             handler.characters(ch, start, length);
  88:         }
  89:     }
  90: 
  91:     /**
  92:      * Returns the handler at the top of the stack.
  93:      *
  94:      * @return The handler.
  95:      */
  96:     public DefaultHandler getCurrentHandler() {
  97:         DefaultHandler result = this;
  98:         if (this.subHandlers != null) {
  99:             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: }