Source for org.jfree.data.xml.ItemHandler

   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:  * ItemHandler.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 org.xml.sax.Attributes;
  44: import org.xml.sax.SAXException;
  45: import org.xml.sax.helpers.DefaultHandler;
  46: 
  47: /**
  48:  * A handler for reading key-value items.
  49:  */
  50: public class ItemHandler extends DefaultHandler implements DatasetTags {
  51: 
  52:     /** The root handler. */
  53:     private RootHandler root;
  54: 
  55:     /** The parent handler (can be the same as root, but not always). */
  56:     private DefaultHandler parent;
  57: 
  58:     /** The key. */
  59:     private Comparable key;
  60: 
  61:     /** The value. */
  62:     private Number value;
  63: 
  64:     /**
  65:      * Creates a new item handler.
  66:      *
  67:      * @param root  the root handler.
  68:      * @param parent  the parent handler.
  69:      */
  70:     public ItemHandler(RootHandler root, DefaultHandler parent) {
  71:         this.root = root;
  72:         this.parent = parent;
  73:         this.key = null;
  74:         this.value = null;
  75:     }
  76: 
  77:     /**
  78:      * Returns the key that has been read by the handler, or <code>null</code>.
  79:      *
  80:      * @return The key.
  81:      */
  82:     public Comparable getKey() {
  83:         return this.key;
  84:     }
  85: 
  86:     /**
  87:      * Sets the key.
  88:      *
  89:      * @param key  the key.
  90:      */
  91:     public void setKey(Comparable key) {
  92:         this.key = key;
  93:     }
  94: 
  95:     /**
  96:      * Returns the key that has been read by the handler, or <code>null</code>.
  97:      *
  98:      * @return The value.
  99:      */
 100:     public Number getValue() {
 101:         return this.value;
 102:     }
 103: 
 104:     /**
 105:      * Sets the value.
 106:      *
 107:      * @param value  the value.
 108:      */
 109:     public void setValue(Number value) {
 110:         this.value = value;
 111:     }
 112: 
 113:     /**
 114:      * The start of an element.
 115:      *
 116:      * @param namespaceURI  the namespace.
 117:      * @param localName  the element name.
 118:      * @param qName  the element name.
 119:      * @param atts  the attributes.
 120:      *
 121:      * @throws SAXException for errors.
 122:      */
 123:     public void startElement(String namespaceURI,
 124:                              String localName,
 125:                              String qName,
 126:                              Attributes atts) throws SAXException {
 127: 
 128:         if (qName.equals(ITEM_TAG)) {
 129:             KeyHandler subhandler = new KeyHandler(this.root, this);
 130:             this.root.pushSubHandler(subhandler);
 131:         }
 132:         else if (qName.equals(VALUE_TAG)) {
 133:             ValueHandler subhandler = new ValueHandler(this.root, this);
 134:             this.root.pushSubHandler(subhandler);
 135:         }
 136:         else {
 137:             throw new SAXException(
 138:                 "Expected <Item> or <Value>...found " + qName
 139:             );
 140:         }
 141: 
 142:     }
 143: 
 144:     /**
 145:      * The end of an element.
 146:      *
 147:      * @param namespaceURI  the namespace.
 148:      * @param localName  the element name.
 149:      * @param qName  the element name.
 150:      */
 151:     public void endElement(String namespaceURI,
 152:                            String localName,
 153:                            String qName) {
 154: 
 155:         if (this.parent instanceof PieDatasetHandler) {
 156:             PieDatasetHandler handler = (PieDatasetHandler) this.parent;
 157:             handler.addItem(this.key, this.value);
 158:             this.root.popSubHandler();
 159:         }
 160:         else if (this.parent instanceof CategorySeriesHandler) {
 161:             CategorySeriesHandler handler = (CategorySeriesHandler) this.parent;
 162:             handler.addItem(this.key, this.value);
 163:             this.root.popSubHandler();
 164:         }
 165: 
 166:     }
 167: 
 168: }