KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > dom4j > io > SAXHelper


1 /*
2  * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
3  *
4  * This software is open source.
5  * See the bottom of this file for the licence.
6  */

7
8 package org.dom4j.io;
9
10 import org.xml.sax.SAXException JavaDoc;
11 import org.xml.sax.SAXNotRecognizedException JavaDoc;
12 import org.xml.sax.SAXNotSupportedException JavaDoc;
13 import org.xml.sax.XMLReader JavaDoc;
14 import org.xml.sax.helpers.XMLReaderFactory JavaDoc;
15
16 /**
17  * <p>
18  * <code>SAXHelper</code> contains some helper methods for working with SAX
19  * and XMLReader objects.
20  * </p>
21  *
22  * @author <a HREF="mailto:james.strachan@metastuff.com">James Strachan </a>
23  * @version $Revision: 1.18 $
24  */

25 class SAXHelper {
26     private static boolean loggedWarning = true;
27
28     protected SAXHelper() {
29     }
30
31     public static boolean setParserProperty(XMLReader JavaDoc reader,
32             String JavaDoc propertyName, Object JavaDoc value) {
33         try {
34             reader.setProperty(propertyName, value);
35
36             return true;
37         } catch (SAXNotSupportedException JavaDoc e) {
38             // ignore
39
} catch (SAXNotRecognizedException JavaDoc e) {
40             // ignore
41
}
42
43         return false;
44     }
45
46     public static boolean setParserFeature(XMLReader JavaDoc reader,
47             String JavaDoc featureName, boolean value) {
48         try {
49             reader.setFeature(featureName, value);
50
51             return true;
52         } catch (SAXNotSupportedException JavaDoc e) {
53             // ignore
54
} catch (SAXNotRecognizedException JavaDoc e) {
55             // ignore
56
}
57
58         return false;
59     }
60
61     /**
62      * Creats a default XMLReader via the org.xml.sax.driver system property or
63      * JAXP if the system property is not set.
64      *
65      * @param validating
66      * DOCUMENT ME!
67      *
68      * @return DOCUMENT ME!
69      *
70      * @throws SAXException
71      * DOCUMENT ME!
72      */

73     public static XMLReader JavaDoc createXMLReader(boolean validating)
74             throws SAXException JavaDoc {
75         XMLReader JavaDoc reader = null;
76
77         if (reader == null) {
78             reader = createXMLReaderViaJAXP(validating, true);
79         }
80
81         if (reader == null) {
82             try {
83                 reader = XMLReaderFactory.createXMLReader();
84             } catch (Exception JavaDoc e) {
85                 if (isVerboseErrorReporting()) {
86                     // log all exceptions as warnings and carry
87
// on as we have a default SAX parser we can use
88
System.out.println("Warning: Caught exception attempting "
89                             + "to use SAX to load a SAX XMLReader ");
90                     System.out.println("Warning: Exception was: " + e);
91                     System.out
92                             .println("Warning: I will print the stack trace "
93                                     + "then carry on using the default "
94                                     + "SAX parser");
95                     e.printStackTrace();
96                 }
97
98                 throw new SAXException JavaDoc(e);
99             }
100         }
101
102         if (reader == null) {
103             throw new SAXException JavaDoc("Couldn't create SAX reader");
104         }
105
106         return reader;
107     }
108
109     /**
110      * This method attempts to use JAXP to locate the SAX2 XMLReader
111      * implementation. This method uses reflection to avoid being dependent
112      * directly on the JAXP classes.
113      *
114      * @param validating
115      * DOCUMENT ME!
116      * @param namespaceAware
117      * DOCUMENT ME!
118      *
119      * @return DOCUMENT ME!
120      */

121     protected static XMLReader JavaDoc createXMLReaderViaJAXP(boolean validating,
122             boolean namespaceAware) {
123         // try use JAXP to load the XMLReader...
124
try {
125             return JAXPHelper.createXMLReader(validating, namespaceAware);
126         } catch (Throwable JavaDoc e) {
127             if (!loggedWarning) {
128                 loggedWarning = true;
129
130                 if (isVerboseErrorReporting()) {
131                     // log all exceptions as warnings and carry
132
// on as we have a default SAX parser we can use
133
System.out.println("Warning: Caught exception attempting "
134                             + "to use JAXP to load a SAX XMLReader");
135                     System.out.println("Warning: Exception was: " + e);
136                     e.printStackTrace();
137                 }
138             }
139         }
140
141         return null;
142     }
143
144     protected static boolean isVerboseErrorReporting() {
145         try {
146             String JavaDoc flag = System.getProperty("org.dom4j.verbose");
147
148             if ((flag != null) && flag.equalsIgnoreCase("true")) {
149                 return true;
150             }
151         } catch (Exception JavaDoc e) {
152             // in case a security exception
153
// happens in an applet or similar JVM
154
}
155
156         return true;
157     }
158 }
159
160 /*
161  * Redistribution and use of this software and associated documentation
162  * ("Software"), with or without modification, are permitted provided that the
163  * following conditions are met:
164  *
165  * 1. Redistributions of source code must retain copyright statements and
166  * notices. Redistributions must also contain a copy of this document.
167  *
168  * 2. Redistributions in binary form must reproduce the above copyright notice,
169  * this list of conditions and the following disclaimer in the documentation
170  * and/or other materials provided with the distribution.
171  *
172  * 3. The name "DOM4J" must not be used to endorse or promote products derived
173  * from this Software without prior written permission of MetaStuff, Ltd. For
174  * written permission, please contact dom4j-info@metastuff.com.
175  *
176  * 4. Products derived from this Software may not be called "DOM4J" nor may
177  * "DOM4J" appear in their names without prior written permission of MetaStuff,
178  * Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
179  *
180  * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
181  *
182  * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
183  * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
184  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
185  * ARE DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE
186  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
187  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
188  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
189  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
190  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
191  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
192  * POSSIBILITY OF SUCH DAMAGE.
193  *
194  * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
195  */

196
Popular Tags