Source code: org/apache/axis/components/encoding/XMLEncoderFactory.java
1 /*
2 * Copyright 2001-2004 The Apache Software Foundation.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package org.apache.axis.components.encoding;
17
18 import org.apache.axis.components.logger.LogFactory;
19 import org.apache.axis.utils.JavaUtils;
20 import org.apache.axis.utils.Messages;
21 import org.apache.commons.discovery.ResourceNameIterator;
22 import org.apache.commons.discovery.resource.ClassLoaders;
23 import org.apache.commons.discovery.resource.names.DiscoverServiceNames;
24 import org.apache.commons.logging.Log;
25
26 import java.io.UnsupportedEncodingException;
27 import java.util.HashMap;
28 import java.util.Map;
29
30 /**
31 * Factory for XMLEncoder
32 *
33 * @author <a href="mailto:jens@void.fm">Jens Schumann</a>
34 * @author <a href="mailto:dims@yahoo.com">Davanum Srinivas</a>
35 */
36 public class XMLEncoderFactory {
37 protected static Log log = LogFactory.getLog(XMLEncoderFactory.class.getName());
38
39 public static final String ENCODING_UTF_8 = "UTF-8";
40 public static final String ENCODING_UTF_16 = "UTF-16";
41 public static final String DEFAULT_ENCODING = ENCODING_UTF_8;
42
43 private static Map encoderMap = new HashMap();
44 private static final String PLUGABLE_PROVIDER_FILENAME = "org.apache.axis.components.encoding.XMLEncoder";
45
46 static {
47 encoderMap.put(ENCODING_UTF_8, new UTF8Encoder());
48 encoderMap.put(ENCODING_UTF_16, new UTF16Encoder());
49 encoderMap.put(ENCODING_UTF_8.toLowerCase(), new UTF8Encoder());
50 encoderMap.put(ENCODING_UTF_16.toLowerCase(), new UTF16Encoder());
51 try {
52 loadPluggableEncoders();
53 } catch (Throwable t){
54 String msg=t + JavaUtils.LS + JavaUtils.stackToString(t);
55 log.info(Messages.getMessage("exception01",msg));
56 }
57 }
58
59 /**
60 * Returns the default encoder
61 * @return
62 */
63 public static XMLEncoder getDefaultEncoder() {
64 try {
65 return getEncoder(DEFAULT_ENCODING);
66 } catch (UnsupportedEncodingException e) {
67 // as far I know J++ VMs will throw this exception
68 throw new IllegalStateException(Messages.getMessage("unsupportedDefaultEncoding00", DEFAULT_ENCODING));
69 }
70 }
71
72 /**
73 * Returns the requested encoder
74 * @param encoding
75 * @return
76 * @throws UnsupportedEncodingException
77 */
78 public static XMLEncoder getEncoder(String encoding) throws UnsupportedEncodingException {
79 XMLEncoder encoder = (XMLEncoder) encoderMap.get(encoding);
80 if (encoder == null) {
81 encoder = new DefaultXMLEncoder(encoding);
82 encoderMap.put(encoding, encoder);
83 }
84 return encoder;
85 }
86
87 /**
88 Look for file META-INF/services/org.apache.axis.components.encoding.XMLEncoder
89 in all the JARS, get the classes listed in those files and add them to
90 encoders list if they are valid encoders.
91
92 Here is how the scheme would work.
93
94 A company providing a new encoder will jar up their encoder related
95 classes in a JAR file. The following file containing the name of the new
96 encoder class is also made part of this JAR file.
97
98 META-INF/services/org.apache.axis.components.encoding.XMLEncoder
99
100 By making this JAR part of the webapp, the new encoder will be
101 automatically discovered.
102 */
103 private static void loadPluggableEncoders() {
104 ClassLoader clzLoader = XMLEncoder.class.getClassLoader();
105 ClassLoaders loaders = new ClassLoaders();
106 loaders.put(clzLoader);
107 DiscoverServiceNames dsn = new DiscoverServiceNames(loaders);
108 ResourceNameIterator iter = dsn.findResourceNames(PLUGABLE_PROVIDER_FILENAME);
109 while (iter.hasNext()) {
110 String className = iter.nextResourceName();
111 try {
112 Object o = Class.forName(className).newInstance();
113 if (o instanceof XMLEncoder) {
114 XMLEncoder encoder = (XMLEncoder) o;
115 encoderMap.put(encoder.getEncoding(), encoder);
116 encoderMap.put(encoder.getEncoding().toLowerCase(), encoder);
117 }
118 } catch (Exception e) {
119 String msg = e + JavaUtils.LS + JavaUtils.stackToString(e);
120 log.info(Messages.getMessage("exception01", msg));
121 continue;
122 }
123 }
124 }
125 }