Source for org.jfree.data.xml.RootHandler

   1: /* ===========================================================
   2:  * JFreeChart : a free chart library for the Java(tm) platform
   3:  * ===========================================================
   4:  *
   5:  * (C) Copyright 2000-2007, 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 2003-2007, by Object Refinery Limited and Contributors.
  31:  *
  32:  * Original Author:  David Gilbert (for Object Refinery Limited);
  33:  * Contributor(s):   -;
  34:  *
  35:  * Changes
  36:  * -------
  37:  * 23-Jan-2003 : Version 1 (DG);
  38:  *
  39:  */
  40: 
  41: package org.jfree.data.xml;
  42: 
  43: import java.util.Stack;
  44: 
  45: import org.xml.sax.SAXException;
  46: import org.xml.sax.helpers.DefaultHandler;
  47: 
  48: /**
  49:  * A SAX handler that delegates work to sub-handlers.
  50:  */
  51: public class RootHandler extends DefaultHandler implements DatasetTags {
  52: 
  53:     /** The sub-handlers. */
  54:     private Stack subHandlers;
  55: 
  56:     /**
  57:      * Creates a new handler.
  58:      */
  59:     public RootHandler() {
  60:         this.subHandlers = new Stack();
  61:     }
  62: 
  63:     /**
  64:      * Returns the stack of sub handlers.
  65:      *
  66:      * @return The sub-handler stack.
  67:      */
  68:     public Stack getSubHandlers() {
  69:         return this.subHandlers;
  70:     }
  71: 
  72:     /**
  73:      * Receives some (or all) of the text in the current element.
  74:      *
  75:      * @param ch  character buffer.
  76:      * @param start  the start index.
  77:      * @param length  the length of the valid character data.
  78:      *
  79:      * @throws SAXException for errors.
  80:      */
  81:     public void characters(char[] ch, int start, int length) 
  82:         throws SAXException {
  83:         DefaultHandler handler = getCurrentHandler();
  84:         if (handler != this) {
  85:             handler.characters(ch, start, length);
  86:         }
  87:     }
  88: 
  89:     /**
  90:      * Returns the handler at the top of the stack.
  91:      *
  92:      * @return The handler.
  93:      */
  94:     public DefaultHandler getCurrentHandler() {
  95:         DefaultHandler result = this;
  96:         if (this.subHandlers != null) {
  97:             if (this.subHandlers.size() > 0) {
  98:                 Object top = this.subHandlers.peek();
  99:                 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: }