1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.jempbox.impl;
18
19 import java.io.File;
20 import java.io.InputStream;
21 import java.io.IOException;
22 import java.io.OutputStream;
23 import java.io.StringWriter;
24
25 import javax.xml.parsers.DocumentBuilder;
26 import javax.xml.parsers.DocumentBuilderFactory;
27 import javax.xml.transform.OutputKeys;
28 import javax.xml.transform.Result;
29 import javax.xml.transform.Transformer;
30 import javax.xml.transform.TransformerException;
31 import javax.xml.transform.TransformerFactory;
32 import javax.xml.transform.dom.DOMSource;
33 import javax.xml.transform.stream.StreamResult;
34
35 import org.apache.jempbox.xmp.Elementable;
36 import org.w3c.dom.Document;
37 import org.w3c.dom.Element;
38 import org.w3c.dom.Node;
39 import org.w3c.dom.NodeList;
40 import org.w3c.dom.Text;
41 import org.xml.sax.InputSource;
42
43 /**
44 * This class with handle some simple XML operations.
45 *
46 * @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
47 * @author <a href="mailto:chris@oezbek.net">Christopher Oezbek</a>
48 *
49 * @version $Revision: 1.4 $
50 */
51 public class XMLUtil
52 {
53 /**
54 * Utility class, should not be instantiated.
55 *
56 */
57 private XMLUtil()
58 {
59 }
60
61 /**
62 * This will parse an XML stream and create a DOM document.
63 *
64 * @param is The stream to get the XML from.
65 * @return The DOM document.
66 * @throws IOException It there is an error creating the dom.
67 */
68 public static Document parse( InputStream is ) throws IOException
69 {
70 try
71 {
72 DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
73 DocumentBuilder builder = builderFactory.newDocumentBuilder();
74 return builder.parse( is );
75 }
76 catch( Exception e )
77 {
78 IOException thrown = new IOException( e.getMessage() );
79 throw thrown;
80 }
81 }
82
83 /**
84 * This will parse an InputSource and create a DOM document.
85 *
86 * @param is The stream to get the XML from.
87 * @return The DOM document.
88 * @throws IOException It there is an error creating the dom.
89 */
90 public static Document parse( InputSource is ) throws IOException
91 {
92 try
93 {
94 DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
95 DocumentBuilder builder = builderFactory.newDocumentBuilder();
96 return builder.parse( is );
97 }
98 catch( Exception e )
99 {
100 IOException thrown = new IOException( e.getMessage() );
101 throw thrown;
102 }
103 }
104
105 /**
106 * This will parse an XML stream and create a DOM document.
107 *
108 * @param fileName The file to get the XML from.
109 * @return The DOM document.
110 * @throws IOException It there is an error creating the dom.
111 */
112 public static Document parse( String fileName ) throws IOException
113 {
114 try
115 {
116 DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
117 DocumentBuilder builder = builderFactory.newDocumentBuilder();
118 return builder.parse( fileName );
119 }
120 catch( Exception e )
121 {
122 IOException thrown = new IOException( e.getMessage() );
123 throw thrown;
124 }
125 }
126
127 /**
128 * Create a new blank XML document.
129 *
130 * @return The new blank XML document.
131 *
132 * @throws IOException If there is an error creating the XML document.
133 */
134 public static Document newDocument() throws IOException
135 {
136 try
137 {
138 DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
139 DocumentBuilder builder = builderFactory.newDocumentBuilder();
140 return builder.newDocument();
141 }
142 catch( Exception e )
143 {
144 IOException thrown = new IOException( e.getMessage() );
145 throw thrown;
146 }
147 }
148
149 /**
150 * Get the first instance of an element by name.
151 *
152 * @param parent The parent to get the element from.
153 * @param elementName The name of the element to look for.
154 * @return The element or null if it is not found.
155 */
156 public static Element getElement( Element parent, String elementName )
157 {
158 Element retval = null;
159 NodeList children = parent.getElementsByTagName( elementName );
160 if( children.getLength() > 0 )
161 {
162 retval = (Element)children.item( 0 );
163 }
164 return retval;
165 }
166
167 /**
168 * Get the integer value of a subnode.
169 *
170 * @param parent The parent element that holds the values.
171 * @param nodeName The name of the node that holds the integer value.
172 *
173 * @return The integer value of the node.
174 */
175 public static Integer getIntValue( Element parent, String nodeName )
176 {
177 String intVal = XMLUtil.getStringValue( XMLUtil.getElement( parent, nodeName ) );
178 Integer retval = null;
179 if( intVal != null )
180 {
181 retval = new Integer( intVal );
182 }
183 return retval;
184 }
185
186 /**
187 * Set the integer value of an element.
188 *
189 * @param parent The parent element that will hold this subelement.
190 * @param nodeName The name of the subelement.
191 * @param intValue The value to set.
192 */
193 public static void setIntValue( Element parent, String nodeName, Integer intValue )
194 {
195 Element currentValue = getElement( parent, nodeName );
196 if( intValue == null )
197 {
198 if( currentValue != null )
199 {
200 parent.removeChild( currentValue );
201 }
202 else
203 {
204 //it doesn't exist so we don't need to remove it.
205 }
206 }
207 else
208 {
209 if( currentValue == null )
210 {
211 currentValue = parent.getOwnerDocument().createElement( nodeName );
212 parent.appendChild( currentValue );
213 }
214 XMLUtil.setStringValue( currentValue, intValue.toString() );
215 }
216 }
217
218 /**
219 * Get the value of a subnode.
220 *
221 * @param parent The parent element that holds the values.
222 * @param nodeName The name of the node that holds the value.
223 *
224 * @return The value of the sub node.
225 */
226 public static String getStringValue( Element parent, String nodeName )
227 {
228 return XMLUtil.getStringValue( XMLUtil.getElement( parent, nodeName ) );
229 }
230
231 /**
232 * Set the value of an element.
233 *
234 * @param parent The parent element that will hold this subelement.
235 * @param nodeName The name of the subelement.
236 * @param nodeValue The value to set.
237 */
238 public static void setStringValue( Element parent, String nodeName, String nodeValue )
239 {
240 Element currentValue = getElement( parent, nodeName );
241 if( nodeValue == null )
242 {
243 if( currentValue != null )
244 {
245 parent.removeChild( currentValue );
246 }
247 else
248 {
249 //it doesn't exist so we don't need to remove it.
250 }
251 }
252 else
253 {
254 if( currentValue == null )
255 {
256 currentValue = parent.getOwnerDocument().createElement( nodeName );
257 parent.appendChild( currentValue );
258 }
259 XMLUtil.setStringValue( currentValue, nodeValue );
260 }
261 }
262
263 /**
264 * This will get the text value of an element.
265 *
266 * @param node The node to get the text value for.
267 * @return The text of the node.
268 */
269 public static String getStringValue( Element node )
270 {
271 String retval = "";
272 NodeList children = node.getChildNodes();
273 for( int i=0; i<children.getLength(); i++ )
274 {
275 Node next = children.item( i );
276 if( next instanceof Text )
277 {
278 retval = next.getNodeValue();
279 }
280 }
281 return retval;
282 }
283
284 /**
285 * This will set the text value of an element.
286 *
287 * @param node The node to get the text value for.
288 * @param value The new value to set the node to.
289 */
290 public static void setStringValue( Element node, String value )
291 {
292 NodeList children = node.getChildNodes();
293 for( int i=0; i<children.getLength(); i++ )
294 {
295 Node next = children.item( i );
296 if( next instanceof Text )
297 {
298 node.removeChild( next );
299 }
300 }
301 node.appendChild( node.getOwnerDocument().createTextNode( value ) );
302 }
303
304 /**
305 * Set an XML element document.
306 *
307 * @param parent The parent document to set the value in.
308 * @param name The name of the XML element to set.
309 * @param node The node to set or clear.
310 */
311 public static void setElementableValue( Element parent, String name, Elementable node )
312 {
313 NodeList nodes = parent.getElementsByTagName( name );
314 if( node == null )
315 {
316 for( int i=0; i<nodes.getLength(); i++ )
317 {
318 parent.removeChild( nodes.item( i ) );
319 }
320 }
321 else
322 {
323 if( nodes.getLength() == 0 )
324 {
325 if( parent.hasChildNodes() )
326 {
327 Node firstChild = parent.getChildNodes().item( 0 );
328 parent.insertBefore( node.getElement(), firstChild );
329 }
330 else
331 {
332 parent.appendChild( node.getElement() );
333 }
334 }
335 else
336 {
337 Node oldNode = nodes.item( 0 );
338 parent.replaceChild( node.getElement(), oldNode );
339 }
340 }
341 }
342
343 /**
344 * Save the XML document to a file.
345 *
346 * @param doc The XML document to save.
347 * @param file The file to save the document to.
348 * @param encoding The encoding to save the file as.
349 *
350 * @throws TransformerException If there is an error while saving the XML.
351 */
352 public static void save( Document doc, String file, String encoding )
353 throws TransformerException
354 {
355 try
356 {
357 Transformer transformer = TransformerFactory.newInstance().newTransformer();
358 transformer.setOutputProperty(OutputKeys.INDENT, "yes");
359 transformer.setOutputProperty(OutputKeys.ENCODING, encoding);
360 transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
361 // initialize StreamResult with File object to save to file
362
363 Result result = new StreamResult(new File(file));
364 DOMSource source = new DOMSource(doc);
365 transformer.transform(source, result);
366 }
367 finally
368 {
369
370 }
371 }
372
373 /**
374 * Save the XML document to an output stream.
375 *
376 * @param doc The XML document to save.
377 * @param outStream The stream to save the document to.
378 * @param encoding The encoding to save the file as.
379 *
380 * @throws TransformerException If there is an error while saving the XML.
381 */
382 public static void save( Node doc, OutputStream outStream, String encoding )
383 throws TransformerException
384 {
385 try
386 {
387 Transformer transformer = TransformerFactory.newInstance().newTransformer();
388 transformer.setOutputProperty(OutputKeys.INDENT, "yes");
389 transformer.setOutputProperty(OutputKeys.ENCODING, encoding);
390 transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
391
392 // initialize StreamResult with File object to save to file
393 Result result = new StreamResult(outStream);
394 DOMSource source = new DOMSource(doc);
395 transformer.transform(source, result);
396 }
397 finally
398 {
399
400 }
401 }
402
403 /**
404 * Convert the document to an array of bytes.
405 *
406 * @param doc The XML document.
407 * @param encoding The encoding of the output data.
408 *
409 * @return The XML document as an array of bytes.
410 *
411 * @throws TransformerException If there is an error transforming to text.
412 */
413 public static byte[] asByteArray( Document doc, String encoding)
414 throws TransformerException
415 {
416 Transformer transformer = TransformerFactory.newInstance().newTransformer();
417 transformer.setOutputProperty(OutputKeys.INDENT, "yes");
418 transformer.setOutputProperty(OutputKeys.ENCODING, encoding);
419 transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
420
421 StringWriter writer = new StringWriter();
422 Result result = new StreamResult(writer);
423 DOMSource source = new DOMSource(doc);
424 transformer.transform(source, result);
425 return writer.getBuffer().toString().getBytes();
426 }
427 }