Source code: edu/ou/kmi/buddyspace/xml/XDataFieldHandler.java
1 /*
2 * License
3 *
4 * The contents of this file are subject to the Jabber Open Source License
5 * Version 1.0 (the "License"). You may not copy or use this file, in either
6 * source code or executable form, except in compliance with the License. You
7 * may obtain a copy of the License at http://www.jabber.com/license/ or at
8 * http://www.opensource.org/.
9 *
10 * Software distributed under the License is distributed on an "AS IS" basis,
11 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 * for the specific language governing rights and limitations under the
13 * License.
14 *
15 * Copyrights
16 *
17 * Shawn Wilton
18 *
19 * Changes
20 *
21 * @author Shawn Wilton <a href="mailto:shawn@black9.net">
22 * <i><shawn@black9.net></i></a>
23 *
24 * @author $Author: brouk $
25 * @version $Revision: 1.2 $
26 *
27 * j.komzak
28 * Changed into XDataFieldHandler
29 */
30
31 package edu.ou.kmi.buddyspace.xml;
32
33 /*
34 * XDataFieldHandler.java
35 *
36 * Project: BuddySpace
37 * (C) Copyright Knowledge Media Institute 2002
38 *
39 *
40 * Created on 5 February 2003, 11:56
41 */
42 import org.jabber.jabberbeans.Extension.*;
43 import org.jabber.jabberbeans.util.*;
44 import org.jabber.jabberbeans.*;
45 import org.jabber.jabberbeans.sax.SubHandler;
46 import org.xml.sax.SAXException;
47 import org.xml.sax.AttributeList;
48
49 /**
50 * Handler class to build <field> objects inside jabber:x:data
51 *
52 * @author Jiri Komzak, Knowledge Media Institute, Open University, United Kingdom
53 */
54 public class XDataFieldHandler extends SubHandler
55 {
56 /** used to capture data between element tags */
57 private StringBuffer elementChars;
58
59 /** builder for XDataField objects */
60 private XDataFieldBuilder builder;
61
62
63 /*
64 * Creates a new <code>XDataFieldHandler</code> instance.
65 */
66 public XDataFieldHandler()
67 {
68 super();
69 builder = new XDataFieldBuilder();
70 }
71
72
73 /*
74 * This is an exact copy of the characters function in the main handler
75 *
76 * @param ch character string detected
77 * @param start start position
78 * @param length length of string
79 * @exception SAXException thrown on error
80 */
81 public void characters(char[] ch, int start, int length) throws SAXException
82 {elementChars.append(ch,start,length);}
83
84
85 /**
86 * Gets called when the underlying engine decides to pass an entity and
87 * all sub-entities off to your subhandler.<p>
88 *
89 * Upon seeing the element that this subhandler handles, we call this
90 * constructor, passing in the attributes.
91 *
92 * @param name name of the element which we are handling.
93 * @param attributes list of attributes on this element
94 */
95 protected final void startHandler(String name,AttributeList attributes)
96 throws SAXException
97 {
98 elementChars=new StringBuffer();
99 builder.reset();
100
101 builder.setType(attributes.getValue("type"));
102 builder.setLabel(attributes.getValue("label"));
103 builder.setVar(attributes.getValue("var"));
104 }
105
106 /*
107 * <code>handleStartElement</code> is overloaded by the new class to
108 * provide logic to handle the element code.
109 *
110 * @param name a <code>String</code> value
111 * @param attributes an <code>AttributeList</code> value
112 * @exception SAXException if an error occurs
113 */
114 protected void handleStartElement(String name, AttributeList attributes) throws SAXException
115 {
116 elementChars=new StringBuffer();
117
118 //Start new handler for items that *may* be containers, but never for namespaces "ns".
119 if ("value".equals(name) || "desc".equals(name))
120 //setChildSubHandler(new SingleValueTagHandler(), name, attributes);
121 return;
122
123 else if ("option".equals(name))
124 setChildSubHandler(new XDataFieldOptionHandler(), name, attributes);
125
126 else if ("required".equals(name))
127 builder.setRequired(true);
128 }
129
130
131 /*
132 * <code>handleEndElement</code> is overloaded by the new class to
133 * provide logic to handle element code.
134 *
135 * @param name a <code>String</code> value
136 * @exception SAXException if an error occurs
137 */
138 protected void handleEndElement(String name) throws SAXException
139 {
140 if("value".equals(name))
141 builder.addValue(new String(elementChars));
142
143 else if("desc".equals(name))
144 builder.setDesc(new String(elementChars));
145 }
146
147
148 /*
149 * Stophandler is the same as end element, except that it is called saying
150 * that the subhandler is no longer in scope.
151 *
152 * @param Object a value being returned to the parent - the parent is
153 * meant to interpret this result.
154 */
155 protected Object stopHandler(String name) throws SAXException
156 {
157 try{return builder.build();}
158 catch (InstantiationException e)
159 {
160 e.fillInStackTrace();
161 throw new SAXException(e);
162 }
163 }
164
165
166 /*
167 * <code>receiveChildData</code> is called when a child handler exits,
168 * returning control to this code. The now-defunct handler along with the
169 * data object are both returned.
170 *
171 * @param subHandler a <code>SubHandler</code> value
172 * @param o an <code>Object</code> value
173 */
174 protected void receiveChildData(SubHandler subHandler, Object o)
175 {
176 //Add the returned object to the child vector
177 builder.addChild((XMLData)o);
178 }
179 }