1 /*
2 * Copyright 2001-2004 (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 * $Id: SAXHelper.java,v 1.15 2004/06/25 08:03:38 maartenc Exp $
8 */
9
10 package org.dom4j.io;
11
12 import org.dom4j.io.aelfred2.SAXDriver;
13 import org.xml.sax.SAXException;
14 import org.xml.sax.SAXNotRecognizedException;
15 import org.xml.sax.SAXNotSupportedException;
16 import org.xml.sax.XMLReader;
17 import org.xml.sax.helpers.XMLReaderFactory;
18
19 /*** <p><code>SAXHelper</code> contains some helper methods for working with
20 * SAX and XMLReader objects.
21 *
22 * @author <a href="mailto:james.strachan@metastuff.com">James Strachan</a>
23 * @version $Revision: 1.15 $
24 */
25 class SAXHelper {
26
27 private static boolean loggedWarning = true;
28
29 public static boolean setParserProperty(XMLReader reader, String propertyName, Object value) {
30 try {
31 reader.setProperty(propertyName, value);
32 return true;
33 }
34 catch (SAXNotSupportedException e) {
35 // ignore
36 }
37 catch (SAXNotRecognizedException e) {
38 // ignore
39 }
40 return false;
41 }
42
43 public static boolean setParserFeature(XMLReader reader, String featureName, boolean value) {
44 try {
45 reader.setFeature(featureName, value);
46 return true;
47 }
48 catch (SAXNotSupportedException e) {
49 // ignore
50 }
51 catch (SAXNotRecognizedException e) {
52 // ignore
53 }
54 return false;
55 }
56
57 /*** Creats a default XMLReader via the org.xml.sax.driver system property
58 * or JAXP if the system property is not set.
59 */
60 public static XMLReader createXMLReader(boolean validating) throws SAXException {
61 XMLReader reader = null;
62 if ( reader == null ) {
63 reader = createXMLReaderViaJAXP( validating, true );
64 }
65 if ( reader == null ) {
66 try {
67 reader = XMLReaderFactory.createXMLReader();
68 }
69 catch (Exception e) {
70 if ( isVerboseErrorReporting() ) {
71 // log all exceptions as warnings and carry
72 // on as we have a default SAX parser we can use
73 System.out.println(
74 "Warning: Caught exception attempting to use SAX to "
75 + "load a SAX XMLReader "
76 );
77 System.out.println( "Warning: Exception was: " + e );
78 System.out.println(
79 "Warning: I will print the stack trace then carry on "
80 + "using the default SAX parser"
81 );
82 e.printStackTrace();
83 }
84 }
85 }
86 if ( reader == null ) {
87 System.out.println(
88 "Warning: Error occurred using SAX to load a SAXParser. " +
89 "Will use Aelfred instead");
90 reader = new SAXDriver();
91 }
92 return reader;
93 }
94
95 /*** This method attempts to use JAXP to locate the
96 * SAX2 XMLReader implementation.
97 * This method uses reflection to avoid being dependent directly
98 * on the JAXP classes.
99 */
100 protected static XMLReader createXMLReaderViaJAXP(boolean validating, boolean namespaceAware) {
101 // try use JAXP to load the XMLReader...
102 try {
103 return JAXPHelper.createXMLReader( validating, namespaceAware );
104 }
105 catch (Throwable e) {
106 if ( ! loggedWarning ) {
107 loggedWarning = true;
108 if ( isVerboseErrorReporting() ) {
109 // log all exceptions as warnings and carry
110 // on as we have a default SAX parser we can use
111 System.out.println(
112 "Warning: Caught exception attempting to use JAXP to "
113 + "load a SAX XMLReader "
114 );
115 System.out.println( "Warning: Exception was: " + e );
116 e.printStackTrace();
117 }
118 }
119 }
120 return null;
121 }
122
123 protected static boolean isVerboseErrorReporting() {
124 try {
125 String flag = System.getProperty( "org.dom4j.verbose" );
126 if ( flag != null && flag.equalsIgnoreCase( "true" ) ) {
127 return true;
128 }
129 }
130 catch (Exception e) {
131 // in case a security exception
132 // happens in an applet or similar JVM
133 }
134 return true;
135 }
136 }
137
138
139
140
141 /*
142 * Redistribution and use of this software and associated documentation
143 * ("Software"), with or without modification, are permitted provided
144 * that the following conditions are met:
145 *
146 * 1. Redistributions of source code must retain copyright
147 * statements and notices. Redistributions must also contain a
148 * copy of this document.
149 *
150 * 2. Redistributions in binary form must reproduce the
151 * above copyright notice, this list of conditions and the
152 * following disclaimer in the documentation and/or other
153 * materials provided with the distribution.
154 *
155 * 3. The name "DOM4J" must not be used to endorse or promote
156 * products derived from this Software without prior written
157 * permission of MetaStuff, Ltd. For written permission,
158 * please contact dom4j-info@metastuff.com.
159 *
160 * 4. Products derived from this Software may not be called "DOM4J"
161 * nor may "DOM4J" appear in their names without prior written
162 * permission of MetaStuff, Ltd. DOM4J is a registered
163 * trademark of MetaStuff, Ltd.
164 *
165 * 5. Due credit should be given to the DOM4J Project -
166 * http://www.dom4j.org
167 *
168 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS
169 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
170 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
171 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
172 * METASTUFF, LTD. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
173 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
174 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
175 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
176 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
177 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
178 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
179 * OF THE POSSIBILITY OF SUCH DAMAGE.
180 *
181 * Copyright 2001-2004 (C) MetaStuff, Ltd. All Rights Reserved.
182 *
183 * $Id: SAXHelper.java,v 1.15 2004/06/25 08:03:38 maartenc Exp $
184 */