1 /*
2 * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package javax.xml.bind;
27
28 import java.io.BufferedReader;
29 import java.io.IOException;
30 import java.io.InputStream;
31 import java.io.InputStreamReader;
32 import java.io.UnsupportedEncodingException;
33 import java.lang.reflect.InvocationTargetException;
34 import java.lang.reflect.Method;
35 import java.net.URL;
36 import java.util.Map;
37 import java.util.Properties;
38 import java.util.StringTokenizer;
39 import java.util.logging.ConsoleHandler;
40 import java.util.logging.Level;
41 import java.util.logging.Logger;
42
43 import static javax.xml.bind.JAXBContext.JAXB_CONTEXT_FACTORY;
44
45 //import java.lang.reflect.InvocationTargetException;
46
47 /**
48 * This class is package private and therefore is not exposed as part of the
49 * JAXB API.
50 *
51 * This code is designed to implement the JAXB 1.0 spec pluggability feature
52 *
53 * @author <ul><li>Ryan Shoemaker, Sun Microsystems, Inc.</li></ul>
54 * @see JAXBContext
55 */
56 class ContextFinder {
57 private static final Logger logger;
58 static {
59 logger = Logger.getLogger("javax.xml.bind");
60 try {
61 if (System.getProperty("jaxb.debug", null) != null) {
62 // disconnect the logger from a bigger framework (if any)
63 // and take the matters into our own hands
64 logger.setUseParentHandlers(false);
65 logger.setLevel(Level.ALL);
66 ConsoleHandler handler = new ConsoleHandler();
67 handler.setLevel(Level.ALL);
68 logger.addHandler(handler);
69 } else {
70 // don't change the setting of this logger
71 // to honor what other frameworks
72 // have done on configurations.
73 }
74 } catch(Throwable t) {
75 // just to be extra safe. in particular System.getProperty may throw
76 // SecurityException.
77 }
78 }
79
80 /**
81 * If the {@link InvocationTargetException} wraps an exception that shouldn't be wrapped,
82 * throw the wrapped exception.
83 */
84 private static void handleInvocationTargetException(InvocationTargetException x) throws JAXBException {
85 Throwable t = x.getTargetException();
86 if( t != null ) {
87 if( t instanceof JAXBException )
88 // one of our exceptions, just re-throw
89 throw (JAXBException)t;
90 if( t instanceof RuntimeException )
91 // avoid wrapping exceptions unnecessarily
92 throw (RuntimeException)t;
93 if( t instanceof Error )
94 throw (Error)t;
95 }
96 }
97
98
99 /**
100 * Determine if two types (JAXBContext in this case) will generate a ClassCastException.
101 *
102 * For example, (targetType)originalType
103 *
104 * @param originalType
105 * The Class object of the type being cast
106 * @param targetType
107 * The Class object of the type that is being cast to
108 * @throws JAXBException
109 * If the cast would fail
110 */
111 private static void handleClassCastException(Class originalType, Class targetType) throws JAXBException {
112 final URL targetTypeURL = which(targetType);
113
114 throw new JAXBException(Messages.format(Messages.ILLEGAL_CAST,
115 // we don't care where the impl class is, we want to know where JAXBContext lives in the impl
116 // class' ClassLoader
117 originalType.getClass().getClassLoader().getResource("javax/xml/bind/JAXBContext.class").toString(),
118 targetTypeURL.toString()));
119 }
120
121 /**
122 * Create an instance of a class using the specified ClassLoader
123 */
124 static JAXBContext newInstance( String contextPath,
125 String className,
126 ClassLoader classLoader,
127 Map properties )
128 throws JAXBException
129 {
130 try {
131 Class spiClass;
132 if (classLoader == null) {
133 spiClass = Class.forName(className);
134 } else {
135 spiClass = classLoader.loadClass(className);
136 }
137
138 /*
139 * javax.xml.bind.context.factory points to a class which has a
140 * static method called 'createContext' that
141 * returns a javax.xml.JAXBContext.
142 */
143
144 Object context = null;
145
146 // first check the method that takes Map as the third parameter.
147 // this is added in 2.0.
148 try {
149 Method m = spiClass.getMethod("createContext",String.class,ClassLoader.class,Map.class);
150 // any failure in invoking this method would be considered fatal
151 context = m.invoke(null,contextPath,classLoader,properties);
152 } catch (NoSuchMethodException e) {
153 ; // it's not an error for the provider not to have this method.
154 }
155
156 if(context==null) {
157 // try the old method that doesn't take properties. compatible with 1.0.
158 // it is an error for an implementation not to have both forms of the createContext method.
159 Method m = spiClass.getMethod("createContext",String.class,ClassLoader.class);
160 // any failure in invoking this method would be considered fatal
161 context = m.invoke(null,contextPath,classLoader);
162 }
163
164 if(!(context instanceof JAXBContext)) {
165 // the cast would fail, so generate an exception with a nice message
166 handleClassCastException(context.getClass(), JAXBContext.class);
167 }
168 return (JAXBContext)context;
169 } catch (ClassNotFoundException x) {
170 throw new JAXBException(
171 Messages.format( Messages.PROVIDER_NOT_FOUND, className ),
172 x);
173 } catch (InvocationTargetException x) {
174 handleInvocationTargetException(x);
175 // for other exceptions, wrap the internal target exception
176 // with a JAXBException
177 Throwable e = x;
178 if(x.getTargetException()!=null)
179 e = x.getTargetException();
180
181 throw new JAXBException( Messages.format( Messages.COULD_NOT_INSTANTIATE, className, e ), e );
182 } catch (RuntimeException x) {
183 // avoid wrapping RuntimeException to JAXBException,
184 // because it indicates a bug in this code.
185 throw x;
186 } catch (Exception x) {
187 // can't catch JAXBException because the method is hidden behind
188 // reflection. Root element collisions detected in the call to
189 // createContext() are reported as JAXBExceptions - just re-throw it
190 // some other type of exception - just wrap it
191 throw new JAXBException(
192 Messages.format( Messages.COULD_NOT_INSTANTIATE, className, x ),
193 x);
194 }
195 }
196
197
198 /**
199 * Create an instance of a class using the specified ClassLoader
200 */
201 static JAXBContext newInstance(
202 Class[] classes,
203 Map properties,
204 String className) throws JAXBException {
205 ClassLoader cl = Thread.currentThread().getContextClassLoader();
206 Class spi;
207 try {
208 logger.fine("Trying to load "+className);
209 if (cl != null)
210 spi = cl.loadClass(className);
211 else
212 spi = Class.forName(className);
213 } catch (ClassNotFoundException e) {
214 throw new JAXBException(e);
215 }
216
217 if(logger.isLoggable(Level.FINE)) {
218 // extra check to avoid costly which operation if not logged
219 logger.fine("loaded "+className+" from "+which(spi));
220 }
221
222 Method m;
223 try {
224 m = spi.getMethod("createContext", Class[].class, Map.class);
225 } catch (NoSuchMethodException e) {
226 throw new JAXBException(e);
227 }
228 try {
229 Object context = m.invoke(null, classes, properties);
230 if(!(context instanceof JAXBContext)) {
231 // the cast would fail, so generate an exception with a nice message
232 handleClassCastException(context.getClass(), JAXBContext.class);
233 }
234 return (JAXBContext)context;
235 } catch (IllegalAccessException e) {
236 throw new JAXBException(e);
237 } catch (InvocationTargetException e) {
238 handleInvocationTargetException(e);
239
240 Throwable x = e;
241 if (e.getTargetException() != null)
242 x = e.getTargetException();
243
244 throw new JAXBException(x);
245 }
246 }
247
248
249 static JAXBContext find(String factoryId, String contextPath, ClassLoader classLoader, Map properties ) throws JAXBException {
250
251 // TODO: do we want/need another layer of searching in $java.home/lib/jaxb.properties like JAXP?
252
253 final String jaxbContextFQCN = JAXBContext.class.getName();
254
255 // search context path for jaxb.properties first
256 StringBuilder propFileName;
257 StringTokenizer packages = new StringTokenizer( contextPath, ":" );
258 String factoryClassName;
259
260 if(!packages.hasMoreTokens())
261 // no context is specified
262 throw new JAXBException(Messages.format(Messages.NO_PACKAGE_IN_CONTEXTPATH));
263
264
265 logger.fine("Searching jaxb.properties");
266
267 while( packages.hasMoreTokens() ) {
268 String packageName = packages.nextToken(":").replace('.','/');
269 // com.acme.foo - > com/acme/foo/jaxb.properties
270 propFileName = new StringBuilder().append(packageName).append("/jaxb.properties");
271
272 Properties props = loadJAXBProperties( classLoader, propFileName.toString() );
273 if (props == null) {
274 continue;
275 } else {
276 if (props.containsKey(factoryId)) {
277 factoryClassName = props.getProperty(factoryId);
278 return newInstance( contextPath, factoryClassName, classLoader, properties );
279 } else {
280 throw new JAXBException(Messages.format(Messages.MISSING_PROPERTY, packageName, factoryId));
281 }
282 }
283 }
284
285 logger.fine("Searching the system property");
286
287 // search for a system property second (javax.xml.bind.JAXBContext)
288 factoryClassName = System.getProperty(jaxbContextFQCN, null);
289 if( factoryClassName != null ) {
290 return newInstance( contextPath, factoryClassName, classLoader, properties );
291 }
292
293 logger.fine("Searching META-INF/services");
294
295 // search META-INF services next
296 BufferedReader r;
297 try {
298 final StringBuilder resource = new StringBuilder().append("META-INF/services/").append(jaxbContextFQCN);
299 final InputStream resourceStream =
300 classLoader.getResourceAsStream(resource.toString());
301
302 if (resourceStream != null) {
303 r = new BufferedReader(new InputStreamReader(resourceStream, "UTF-8"));
304 factoryClassName = r.readLine().trim();
305 return newInstance(contextPath, factoryClassName, classLoader, properties);
306 } else {
307 logger.fine("Unable to load:" + resource.toString());
308 }
309 } catch (UnsupportedEncodingException e) {
310 // should never happen
311 throw new JAXBException(e);
312 } catch (IOException e) {
313 throw new JAXBException(e);
314 }
315
316 // else no provider found
317 logger.fine("Trying to create the platform default provider");
318 return newInstance(contextPath, PLATFORM_DEFAULT_FACTORY_CLASS, classLoader, properties);
319 }
320
321 // TODO: log each step in the look up process
322 static JAXBContext find( Class[] classes, Map properties ) throws JAXBException {
323
324 // TODO: do we want/need another layer of searching in $java.home/lib/jaxb.properties like JAXP?
325
326 final String jaxbContextFQCN = JAXBContext.class.getName();
327 String factoryClassName;
328
329 // search for jaxb.properties in the class loader of each class first
330 for (Class c : classes) {
331 ClassLoader classLoader = c.getClassLoader();
332 Package pkg = c.getPackage();
333 if(pkg==null)
334 continue; // this is possible for primitives, arrays, and classes that are loaded by poorly implemented ClassLoaders
335 String packageName = pkg.getName().replace('.', '/');
336
337 // TODO: do we want to optimize away searching the same package? org.Foo, org.Bar, com.Baz
338 // classes from the same package might come from different class loades, so it might be a bad idea
339
340 // TODO: it's easier to look things up from the class
341 // c.getResourceAsStream("jaxb.properties");
342
343 // build the resource name and use the property loader code
344 String resourceName = packageName+"/jaxb.properties";
345 logger.fine("Trying to locate "+resourceName);
346 Properties props = loadJAXBProperties(classLoader, resourceName);
347 if (props == null) {
348 logger.fine(" not found");
349 continue;
350 } else {
351 logger.fine(" found");
352 if (props.containsKey(JAXB_CONTEXT_FACTORY)) {
353 // trim() seems redundant, but adding to satisfy customer complaint
354 factoryClassName = props.getProperty(JAXB_CONTEXT_FACTORY).trim();
355 return newInstance(classes, properties, factoryClassName);
356 } else {
357 throw new JAXBException(Messages.format(Messages.MISSING_PROPERTY, packageName, JAXB_CONTEXT_FACTORY));
358 }
359 }
360 }
361
362 // search for a system property second (javax.xml.bind.JAXBContext)
363 logger.fine("Checking system property "+jaxbContextFQCN);
364 factoryClassName = System.getProperty(jaxbContextFQCN, null);
365 if( factoryClassName != null ) {
366 logger.fine(" found "+factoryClassName);
367 return newInstance( classes, properties, factoryClassName );
368 }
369 logger.fine(" not found");
370
371 // search META-INF services next
372 logger.fine("Checking META-INF/services");
373 BufferedReader r;
374 try {
375 final String resource = new StringBuilder("META-INF/services/").append(jaxbContextFQCN).toString();
376 ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
377 URL resourceURL;
378 if(classLoader==null)
379 resourceURL = ClassLoader.getSystemResource(resource);
380 else
381 resourceURL = classLoader.getResource(resource);
382
383 if (resourceURL != null) {
384 logger.fine("Reading "+resourceURL);
385 r = new BufferedReader(new InputStreamReader(resourceURL.openStream(), "UTF-8"));
386 factoryClassName = r.readLine().trim();
387 return newInstance(classes, properties, factoryClassName);
388 } else {
389 logger.fine("Unable to find: " + resource);
390 }
391 } catch (UnsupportedEncodingException e) {
392 // should never happen
393 throw new JAXBException(e);
394 } catch (IOException e) {
395 throw new JAXBException(e);
396 }
397
398 // else no provider found
399 logger.fine("Trying to create the platform default provider");
400 return newInstance(classes, properties, PLATFORM_DEFAULT_FACTORY_CLASS);
401 }
402
403
404 private static Properties loadJAXBProperties( ClassLoader classLoader,
405 String propFileName )
406 throws JAXBException {
407
408 Properties props = null;
409
410 try {
411 URL url;
412 if(classLoader==null)
413 url = ClassLoader.getSystemResource(propFileName);
414 else
415 url = classLoader.getResource( propFileName );
416
417 if( url != null ) {
418 logger.fine("loading props from "+url);
419 props = new Properties();
420 InputStream is = url.openStream();
421 props.load( is );
422 is.close();
423 }
424 } catch( IOException ioe ) {
425 logger.log(Level.FINE,"Unable to load "+propFileName,ioe);
426 throw new JAXBException( ioe.toString(), ioe );
427 }
428
429 return props;
430 }
431
432
433 /**
434 * Search the given ClassLoader for an instance of the specified class and
435 * return a string representation of the URL that points to the resource.
436 *
437 * @param clazz
438 * The class to search for
439 * @param loader
440 * The ClassLoader to search. If this parameter is null, then the
441 * system class loader will be searched
442 * @return
443 * the URL for the class or null if it wasn't found
444 */
445 static URL which(Class clazz, ClassLoader loader) {
446
447 String classnameAsResource = clazz.getName().replace('.', '/') + ".class";
448
449 if(loader == null) {
450 loader = ClassLoader.getSystemClassLoader();
451 }
452
453 return loader.getResource(classnameAsResource);
454 }
455
456 /**
457 * Get the URL for the Class from it's ClassLoader.
458 *
459 * Convenience method for {@link #which(Class, ClassLoader)}.
460 *
461 * Equivalent to calling: which(clazz, clazz.getClassLoader())
462 *
463 * @param clazz
464 * The class to search for
465 * @return
466 * the URL for the class or null if it wasn't found
467 */
468 static URL which(Class clazz) {
469 return which(clazz, clazz.getClassLoader());
470 }
471
472 /**
473 * When JAXB is in J2SE, rt.jar has to have a JAXB implementation.
474 * However, rt.jar cannot have META-INF/services/javax.xml.bind.JAXBContext
475 * because if it has, it will take precedence over any file that applications have
476 * in their jar files.
477 *
478 * <p>
479 * When the user bundles his own JAXB implementation, we'd like to use it, and we
480 * want the platform default to be used only when there's no other JAXB provider.
481 *
482 * <p>
483 * For this reason, we have to hard-code the class name into the API.
484 */
485 private static final String PLATFORM_DEFAULT_FACTORY_CLASS = "com.sun.xml.internal.bind.v2.ContextFactory";
486 }
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