1 package org.apache.lucene.xmlparser;
2 import java.io.Reader;
3
4 import javax.xml.parsers.DocumentBuilder;
5 import javax.xml.parsers.DocumentBuilderFactory;
6
7 import org.w3c.dom.Document;
8 import org.w3c.dom.Element;
9 import org.w3c.dom.Node;
10 import org.xml.sax.InputSource;
11 /**
12 * Licensed to the Apache Software Foundation (ASF) under one or more
13 * contributor license agreements. See the NOTICE file distributed with
14 * this work for additional information regarding copyright ownership.
15 * The ASF licenses this file to You under the Apache License, Version 2.0
16 * (the "License"); you may not use this file except in compliance with
17 * the License. You may obtain a copy of the License at
18 *
19 * http://www.apache.org/licenses/LICENSE-2.0
20 *
21 * Unless required by applicable law or agreed to in writing, software
22 * distributed under the License is distributed on an "AS IS" BASIS,
23 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
24 * See the License for the specific language governing permissions and
25 * limitations under the License.
26 */
27
28 /**
29 *
30 */
31 public class DOMUtils
32 {
33 public static Element getChildByTagOrFail(Element e, String name) throws ParserException
34 {
35 Element kid = getChildByTagName(e, name);
36 if (null == kid)
37 {
38 throw new ParserException(e.getTagName() + " missing \"" + name
39 + "\" child element");
40 }
41 return kid;
42 }
43
44 public static Element getFirstChildOrFail(Element e) throws ParserException
45 {
46 Element kid = getFirstChildElement(e);
47 if (null == kid)
48 {
49 throw new ParserException(e.getTagName()
50 + " does not contain a child element");
51 }
52 return kid;
53 }
54
55 public static String getAttributeOrFail(Element e, String name) throws ParserException
56 {
57 String v = e.getAttribute(name);
58 if (null == v)
59 {
60 throw new ParserException(e.getTagName() + " missing \"" + name
61 + "\" attribute");
62 }
63 return v;
64 }
65 public static String getAttributeWithInheritanceOrFail(Element e, String name) throws ParserException
66 {
67 String v = getAttributeWithInheritance(e, name);
68 if (null == v)
69 {
70 throw new ParserException(e.getTagName() + " missing \"" + name
71 + "\" attribute");
72 }
73 return v;
74 }
75 public static String getNonBlankTextOrFail(Element e) throws ParserException
76 {
77 String v = getText(e);
78 if (null != v)
79 v = v.trim();
80 if (null == v || 0 == v.length())
81 {
82 throw new ParserException(e.getTagName() + " has no text");
83 }
84 return v;
85 }
86
87
88
89
90
91
92 /* Convenience method where there is only one child Element of a given name */
93 public static Element getChildByTagName(Element e, String name)
94 {
95 for (Node kid = e.getFirstChild(); kid != null; kid = kid.getNextSibling())
96 {
97 if( (kid.getNodeType()==Node.ELEMENT_NODE) && (name.equals(kid.getNodeName())) )
98 {
99 return (Element)kid;
100 }
101 }
102 return null;
103 }
104
105 /**
106 * Returns an attribute value from this node, or first parent node with this attribute defined
107 * @param element
108 * @param attributeName
109 * @return A non-zero-length value if defined, otherwise null
110 */
111 public static String getAttributeWithInheritance(Element element, String attributeName)
112 {
113 String result=element.getAttribute(attributeName);
114 if( (result==null)|| ("".equals(result) ) )
115 {
116 Node n=element.getParentNode();
117 if((n==element)||(n==null))
118 {
119 return null;
120 }
121 if(n instanceof Element)
122 {
123 Element parent=(Element) n;
124 return getAttributeWithInheritance(parent,attributeName);
125 }
126 return null; //we reached the top level of the document without finding attribute
127 }
128 return result;
129 }
130
131
132
133 /* Convenience method where there is only one child Element of a given name */
134 public static String getChildTextByTagName(Element e, String tagName)
135 {
136 Element child=getChildByTagName(e,tagName);
137 if(child!=null)
138 {
139 return getText(child);
140 }
141 return null;
142 }
143
144 /* Convenience method to append a new child with text*/
145 public static Element insertChild(Element parent, String tagName, String text)
146 {
147 Element child = parent.getOwnerDocument().createElement(tagName);
148 parent.appendChild(child);
149 if(text!=null)
150 {
151 child.appendChild(child.getOwnerDocument().createTextNode(text));
152 }
153 return child;
154 }
155
156 public static String getAttribute(Element element, String attributeName, String deflt)
157 {
158 String result=element.getAttribute(attributeName);
159 if( (result==null)|| ("".equals(result) ) )
160 {
161 return deflt;
162 }
163 return result;
164 }
165 public static float getAttribute(Element element, String attributeName, float deflt)
166 {
167 String result=element.getAttribute(attributeName);
168 if( (result==null)|| ("".equals(result) ) )
169 {
170 return deflt;
171 }
172 return Float.parseFloat(result);
173 }
174
175 public static int getAttribute(Element element, String attributeName, int deflt)
176 {
177 String result=element.getAttribute(attributeName);
178 if( (result==null)|| ("".equals(result) ) )
179 {
180 return deflt;
181 }
182 return Integer.parseInt(result);
183 }
184
185 public static boolean getAttribute(Element element, String attributeName,
186 boolean deflt)
187 {
188 String result = element.getAttribute(attributeName);
189 if ((result == null) || ("".equals(result)))
190 {
191 return deflt;
192 }
193 return Boolean.valueOf(result).booleanValue();
194 }
195
196 /* Returns text of node and all child nodes - without markup */
197 //MH changed to Node from Element 25/11/2005
198 public static String getText(Node e)
199 {
200 StringBuilder sb=new StringBuilder();
201 getTextBuffer(e, sb);
202 return sb.toString();
203 }
204
205 public static Element getFirstChildElement(Element element)
206 {
207 for (Node kid = element.getFirstChild(); kid != null; kid = kid
208 .getNextSibling())
209 {
210 if (kid.getNodeType() == Node.ELEMENT_NODE)
211 {
212 return (Element) kid;
213 }
214 }
215 return null;
216 }
217
218 private static void getTextBuffer(Node e, StringBuilder sb)
219 {
220 for (Node kid = e.getFirstChild(); kid != null; kid = kid.getNextSibling())
221 {
222 switch(kid.getNodeType())
223 {
224 case Node.TEXT_NODE:
225 {
226 sb.append(kid.getNodeValue());
227 break;
228 }
229 case Node.ELEMENT_NODE:
230 {
231 getTextBuffer(kid, sb);
232 break;
233 }
234 case Node.ENTITY_REFERENCE_NODE:
235 {
236 getTextBuffer(kid, sb);
237 break;
238 }
239 }
240 }
241 }
242
243 /**
244 * Helper method to parse an XML file into a DOM tree, given a reader.
245 * @param is reader of the XML file to be parsed
246 * @return an org.w3c.dom.Document object
247 */
248 public static Document loadXML(Reader is)
249 {
250
251 DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
252 DocumentBuilder db = null;
253
254 try
255 {
256 db = dbf.newDocumentBuilder();
257 }
258 catch (Exception se)
259 {
260 throw new RuntimeException("Parser configuration error", se);
261 }
262
263 // Step 3: parse the input file
264 org.w3c.dom.Document doc = null;
265 try
266 {
267 doc = db.parse(new InputSource(is));
268 //doc = db.parse(is);
269 }
270 catch (Exception se)
271 {
272 throw new RuntimeException("Error parsing file:" + se, se);
273 }
274
275 return doc;
276 }
277 }
278
279
280