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16 package org.apache.cocoon.components.serializers.encoding;
17
18 import java.io.ByteArrayOutputStream  ;
19 import java.io.File ;
20 import java.io.PrintWriter ;
21 import java.io.PrintStream ;
22 import java.io.IOException ;
23 import java.io.OutputStreamWriter ;
24 import java.io.UnsupportedEncodingException ;
25 import java.net.URL ;
26 import java.util.Enumeration ;
27 import java.util.HashMap ;
28 import java.util.zip.ZipEntry ;
29 import java.util.zip.ZipFile ;
30
31
37 public final class CharsetFactory {
38
39
40 private static final String CHARSET_LOOKUP_CLASS =
41 "org/apache/cocoon/components/serializers/encoding/cs_US_ASCII.class";
42
43
44 private static CharsetFactory instance = new CharsetFactory();
45
46
47 private Charset defaultCharset = null;
48
49
50 private Charset unknownCharset = null;
51
52
53 private HashMap charsets = new HashMap ();
54
55
58 private CharsetFactory() {
59 super();
60 this.unknownCharset = new UnknownCharset();
61
62 ClassLoader loader = Thread.currentThread().getContextClassLoader();
63 URL url = loader.getResource(CHARSET_LOOKUP_CLASS);
64
65 if (url == null) {
66 throw new CharsetFactoryException("Unable to load charsets "
67 + "because their classes are not present", null);
68 }
69
70 if ("jar".equals(url.getProtocol())) {
71 this.loadCharsetsFromJar(url);
72 } else if ("file".equals(url.getProtocol())) {
73 this.loadCharsetsFromFile(url);
74 } else {
75 throw new CharsetFactoryException("Unable to load charsets " +
76 "from protocol \"" + url.getProtocol() + "\"", null);
77 }
78
79 ByteArrayOutputStream otmp = new ByteArrayOutputStream ();
80 OutputStreamWriter wtmp = new OutputStreamWriter (otmp);
81 String etmp = wtmp.getEncoding();
82 try {
83 defaultCharset = this.getCharset(etmp);
84 } catch (UnsupportedEncodingException exception) {
85 throw new CharsetFactoryException("The default encoding of this "
86 + "JVM \"" + etmp + "\" is not supported", exception);
87 }
88
89 }
90
91
94 private void loadCharset(Charset charset) {
95 this.charsets.put(charset.getName().toLowerCase(), charset);
96 String aliases[] = charset.getAliases();
97 for (int x = 0; x < aliases.length; x++) {
98 this.charsets.put(aliases[x].toLowerCase(), charset);
99 }
100 }
101
102
105 private void loadCharset(String clazz) {
106 try {
107 Class c = Class.forName(clazz);
108 Object o = c.newInstance();
109 if (o instanceof Charset) {
110 loadCharset((Charset)o);
111 }
112 } catch (Exception exception) {
113 throw new CharsetFactoryException("Unable to instantiate class \""
114 + clazz + "\"", exception);
115 }
116 }
117
118
122 private void loadCharsetsFromJar(URL url) {
123 try {
124 String file = url.getFile();
125 String mtch = file.substring(file.indexOf('!'));
126 file = file.substring(5, file.indexOf('!'));
127 mtch = mtch.substring(2, mtch.lastIndexOf('/') + 1) + "cs_";
128
129 ZipFile zip = new ZipFile (file);
130 Enumeration enumeration = zip.entries();
131 while (enumeration.hasMoreElements()) {
132 ZipEntry entry = (ZipEntry )enumeration.nextElement();
133 String name = entry.getName();
134 if ((! name.startsWith(mtch)) ||
135 (! name.endsWith(".class"))) continue;
136 name = name.substring(mtch.length());
137 name = ".cs_" + name.substring(0, name.length() - 6);
138 name = this.getClass().getPackage().getName() + name;
139 loadCharset(name);
140 }
141 } catch (IOException exception) {
142 throw new CharsetFactoryException("Unable to access JAR \""
143 + url.toString() + "\"", exception);
144 }
145 }
146
147
151 private void loadCharsetsFromFile(URL url) {
152 File file = new File (url.getFile()).getParentFile();
153 String children[] = file.list();
154 for (int x = 0; x < children.length; x++) {
155 String child = children[x];
156 if ((! child.startsWith("cs_")) ||
157 (! child.endsWith(".class"))) continue;
158 child = '.' + child.substring(0, child.length() - 6);
159 child = this.getClass().getPackage().getName() + child;
160 this.loadCharset(child);
161 }
162 }
163
164
167 public static CharsetFactory newInstance() {
168 if (instance != null) return (instance);
169 synchronized (CharsetFactory.class) {
170 if (instance != null) return (instance);
171 instance = new CharsetFactory();
172 }
173 return(instance);
174 }
175
176
182 public Charset getCharset() {
183 return(unknownCharset);
184 }
185
186
190 public Charset getDefaultCharset() {
191 return(defaultCharset);
192 }
193
194
200 public Charset getCharset(String name)
201 throws UnsupportedEncodingException {
202 if (name == null) return(this.getDefaultCharset());
203 Charset charset = (Charset)this.charsets.get(name.toLowerCase());
204 if (charset != null) return(charset);
205 throw new UnsupportedEncodingException ("Unsupported charset \""
206 + name + "\"");
207 }
208
209
213 private static class CharsetFactoryException extends RuntimeException {
214
215
216 private Exception exception = null;
217
218
221 private CharsetFactoryException(String message, Exception exception) {
222 super(message == null? exception.getMessage(): message);
223 this.exception = exception;
224 }
225
226
229 public Exception getException() {
230 return(this.exception);
231 }
232
233
237 public void printStackTrace(PrintWriter out) {
238 super.printStackTrace(out);
239 if (this.exception != null) {
240 out.print("Root cause: ");
241 this.exception.printStackTrace(out);
242 }
243 }
244
245
249 public void printStackTrace(PrintStream out) {
250 super.printStackTrace(out);
251 if (this.exception != null) {
252 out.print("Root cause: ");
253 this.exception.printStackTrace(out);
254 }
255 }
256 }
257 }
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