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1   /*
2    * $Id: ExceptionHelper.java 10415 2008-01-21 10:46:37Z dirk.olmes $
3    * --------------------------------------------------------------------------------------
4    * Copyright (c) MuleSource, Inc.  All rights reserved.  http://www.mulesource.com
5    *
6    * The software in this package is published under the terms of the CPAL v1.0
7    * license, a copy of which has been included with this distribution in the
8    * LICENSE.txt file.
9    */
10  
11  package org.mule.config;
12  
13  import org.mule.MuleRuntimeException;
14  import org.mule.config.i18n.MessageFactory;
15  import org.mule.umo.UMOException;
16  import org.mule.util.ClassUtils;
17  import org.mule.util.SpiUtils;
18  import org.mule.util.StringUtils;
19  
20  import java.io.IOException;
21  import java.io.InputStream;
22  import java.util.ArrayList;
23  import java.util.HashMap;
24  import java.util.Iterator;
25  import java.util.List;
26  import java.util.Map;
27  import java.util.Properties;
28  
29  import org.apache.commons.collections.MapUtils;
30  import org.apache.commons.logging.Log;
31  import org.apache.commons.logging.LogFactory;
32  
33  /**
34   * <code>ExceptionHelper</code> provides a number of helper functions that can be
35   * useful for dealing with Mule exceptions. This class has 3 core functions - <p/>
36   * 1. ErrorCode lookup. A corresponding Mule error code can be found using for a
37   * given Mule exception 2. Addtional Error information such as Java doc url for a
38   * given exception can be resolved using this class 3. Error code mappings can be
39   * looked up by providing the the protocol to map to and the Mule exception.
40   */
41  
42  public final class ExceptionHelper
43  {
44      /**
45       * This is the property to set the error code to no the message it is the
46       * property name the Transport provider uses set the set the error code on the
47       * underlying message
48       */
49      public static final String ERROR_CODE_PROPERTY = "error.code.property";
50  
51      /**
52       * a comma-separated list of other protocols the mappings in a file can be
53       * applied to
54       */
55      public static final String APPLY_TO_PROPERTY = "apply.to";
56  
57      /**
58       * logger used by this class
59       */
60      protected static final Log logger = LogFactory.getLog(ExceptionHelper.class);
61  
62      private static String J2SE_VERSION = "";
63  
64      /** todo How do you get the j2ee version?? */
65      private static final String J2EE_VERSION = "1.3ee";
66  
67      private static Properties errorDocs = new Properties();
68      private static Properties errorCodes = new Properties();
69      private static Map reverseErrorCodes = null;
70      private static Map errorMappings = new HashMap();
71  
72      private static int exceptionThreshold = 0;
73      private static boolean verbose = true;
74  
75      private static boolean initialised = false;
76  
77      /**
78       * A list of the exception readers to use for different types of exceptions
79       */
80      private static List exceptionReaders = new ArrayList();
81  
82      /**
83       * The default ExceptionReader which will be used for most types of exceptions
84       */
85      private static ExceptionReader defaultExceptionReader = new DefaultExceptionReader();
86  
87      static
88      {
89          initialise();
90      }
91  
92      /** Do not instanciate. */
93      private ExceptionHelper ()
94      {
95          // no-op
96      }
97  
98      public static void initialise()
99      {
100         try
101         {
102             if (initialised)
103             {
104                 return;
105             }
106 
107             registerExceptionReader(new UMOExceptionReader());
108             registerExceptionReader(new NamingExceptionReader());
109             J2SE_VERSION = System.getProperty("java.specification.version");
110 
111             InputStream is = SpiUtils.findServiceDescriptor("org/mule/config",
112                 "mule-exception-codes.properties", ExceptionHelper.class);
113             if (is == null)
114             {
115                 throw new IllegalArgumentException(
116                     "Failed to load resource: META_INF/services/org/mule/config/mule-exception-codes.properties");
117             }
118             errorCodes.load(is);
119             reverseErrorCodes = MapUtils.invertMap(errorCodes);
120             is = SpiUtils.findServiceDescriptor("org/mule/config", "mule-exception-config.properties",
121                 ExceptionHelper.class);
122             if (is == null)
123             {
124                 throw new IllegalArgumentException(
125                     "Failed to load resource: META_INF/services/org/mule/config/mule-exception-config.properties");
126             }
127             errorDocs.load(is);
128 
129             initialised = true;
130         }
131         catch (IOException e)
132         {
133             throw new MuleRuntimeException(
134                 MessageFactory.createStaticMessage("Failed to load Exception resources"),
135                 e);
136         }
137     }
138 
139     public static int getErrorCode(Class exception)
140     {
141         String code = errorCodes.getProperty(exception.getName(), "-1");
142         return Integer.parseInt(code);
143     }
144 
145     public static Class getErrorClass(int code)
146     {
147         String key = String.valueOf(code);
148         Object clazz = reverseErrorCodes.get(key);
149         if (clazz == null)
150         {
151             return null;
152         }
153         else if (clazz instanceof Class)
154         {
155             return (Class) clazz;
156         }
157         else
158         {
159             try
160             {
161                 clazz = ClassUtils.loadClass(clazz.toString(), ExceptionHelper.class);
162             }
163             catch (ClassNotFoundException e)
164             {
165                 logger.error(e.getMessage(), e);
166                 return null;
167             }
168             reverseErrorCodes.put(key, clazz);
169             return (Class) clazz;
170         }
171     }
172 
173     public static String getErrorMapping(String protocol, int code)
174     {
175         Class c = getErrorClass(code);
176         if (c != null)
177         {
178             return getErrorMapping(protocol, c);
179         }
180         else
181         {
182             logger.error("Class not known for code: " + code);
183             return "-1";
184         }
185     }
186 
187     private static Properties getErrorMappings(String protocol)
188     {
189         Object m = errorMappings.get(protocol);
190         if (m != null)
191         {
192             if (m instanceof Properties)
193             {
194                 return (Properties) m;
195             }
196             else
197             {
198                 return null;
199             }
200         }
201         else
202         {
203             InputStream is = SpiUtils.findServiceDescriptor("org/mule/config",
204                 protocol + "-exception-mappings.properties", ExceptionHelper.class);
205             if (is == null)
206             {
207                 errorMappings.put(protocol, "not found");
208                 logger.warn("Failed to load error mappings from: META-INF/services/org/mule/config/"
209                             + protocol
210                             + "-exception-mappings.properties. This may be because there are no error code mappings for protocol: "
211                             + protocol);
212                 return null;
213             }
214             Properties p = new Properties();
215             try
216             {
217                 p.load(is);
218             }
219             catch (IOException e)
220             {
221                 throw new MuleRuntimeException(
222                     MessageFactory.createStaticMessage("Failed to load Exception resources"), e);
223             }
224             errorMappings.put(protocol, p);
225             String applyTo = p.getProperty(APPLY_TO_PROPERTY, null);
226             if (applyTo != null)
227             {
228                 String[] protocols = StringUtils.splitAndTrim(applyTo, ",");
229                 for (int i = 0; i < protocols.length; i++)
230                 {
231                     errorMappings.put(protocols[i], p);
232                 }
233             }
234             return p;
235         }
236     }
237 
238     public static String getErrorCodePropertyName(String protocol)
239     {
240         protocol = protocol.toLowerCase();
241         Properties mappings = getErrorMappings(protocol);
242         if (mappings == null)
243         {
244             return null;
245         }
246         return mappings.getProperty(ERROR_CODE_PROPERTY);
247     }
248 
249     public static String getErrorMapping(String protocol, Class exception)
250     {
251         protocol = protocol.toLowerCase();
252         Properties mappings = getErrorMappings(protocol);
253         if (mappings == null)
254         {
255             logger.info("No mappings found for protocol: " + protocol);
256             return String.valueOf(getErrorCode(exception));
257         }
258 
259         Class clazz = exception;
260         String code = null;
261         while (!clazz.equals(Object.class))
262         {
263             code = mappings.getProperty(clazz.getName());
264             if (code == null)
265             {
266                 clazz = clazz.getSuperclass();
267             }
268             else
269             {
270                 return code;
271             }
272         }
273         code = String.valueOf(getErrorCode(exception));
274         // Finally lookup mapping based on error code and return the Mule error
275         // code if a match is not found
276         return mappings.getProperty(code, code);
277     }
278 
279     public static String getJavaDocUrl(Class exception)
280     {
281         return getDocUrl("javadoc.", exception.getName());
282     }
283 
284     public static String getDocUrl(Class exception)
285     {
286         return getDocUrl("doc.", exception.getName());
287     }
288 
289     private static String getDocUrl(String prefix, String packageName)
290     {
291         String key = prefix;
292         if (packageName.startsWith("java.") || packageName.startsWith("javax."))
293         {
294             key += J2SE_VERSION;
295         }
296         String url = getUrl(key, packageName);
297         if (url == null && (packageName.startsWith("java.") || packageName.startsWith("javax.")))
298         {
299             key = prefix + J2EE_VERSION;
300             url = getUrl(key, packageName);
301         }
302         if (url != null)
303         {
304             if (!url.endsWith("/"))
305             {
306                 url += "/";
307             }
308             String s = packageName.replaceAll("[.]", "/");
309             s += ".html";
310             url += s;
311         }
312 
313         /*
314          * If the exception is actually expected to occur by the calling code, the
315          * following output becomes misleading when reading the logs. if
316          * (logger.isDebugEnabled()) { if ("javadoc".equalsIgnoreCase(prefix)) {
317          * logger.debug("Javadoc Url for package '" + packageName + "' is: " + url); }
318          * else if ("doc".equalsIgnoreCase(prefix)) { logger.debug("Online Doc Url
319          * for package '" + packageName + "' is: " + url); } else {
320          * logger.debug(prefix + " Url for package '" + packageName + "' is: " +
321          * url); } }
322          */
323         return url;
324     }
325 
326     private static String getUrl(String key, String packageName)
327     {
328         String url = null;
329         if (!key.endsWith("."))
330         {
331             key += ".";
332         }
333         while (packageName.length() > 0)
334         {
335             url = errorDocs.getProperty(key + packageName, null);
336             if (url == null)
337             {
338                 int i = packageName.lastIndexOf(".");
339                 if (i == -1)
340                 {
341                     packageName = "";
342                 }
343                 else
344                 {
345                     packageName = packageName.substring(0, i);
346                 }
347             }
348             else
349             {
350                 break;
351             }
352         }
353         return url;
354     }
355 
356     public static Throwable getRootException(Throwable t)
357     {
358         Throwable cause = t;
359         Throwable root = null;
360         while (cause != null)
361         {
362             root = cause;
363             cause = getExceptionReader(cause).getCause(cause);
364             // address some misbehaving exceptions, avoid endless loop
365             if (t == cause)
366             {
367                 break;
368             }
369         }
370         return root;
371     }
372 
373     public static Throwable getRootParentException(Throwable t)
374     {
375         Throwable cause = t;
376         Throwable parent = t;
377         while (cause != null)
378         {
379             if (cause.getCause() == null)
380             {
381                 return parent;
382             }
383             parent = cause;
384             cause = getExceptionReader(cause).getCause(cause);
385             // address some misbehaving exceptions, avoid endless loop
386             if (t == cause)
387             {
388                 break;
389             }
390         }
391         return t;
392     }
393 
394     public static UMOException getRootMuleException(Throwable t)
395     {
396         Throwable cause = t;
397         UMOException umoException = null;
398         while (cause != null)
399         {
400             if (cause instanceof UMOException)
401             {
402                 umoException = (UMOException) cause;
403             }
404             cause = getExceptionReader(cause).getCause(cause);
405             // address some misbehaving exceptions, avoid endless loop
406             if (t == cause)
407             {
408                 break;
409             }
410         }
411         return umoException;
412     }
413 
414     public static List getExceptionsAsList(Throwable t)
415     {
416         List exceptions = new ArrayList();
417         Throwable cause = t;
418         while (cause != null)
419         {
420             exceptions.add(0, cause);
421             cause = getExceptionReader(cause).getCause(cause);
422             // address some misbehaving exceptions, avoid endless loop
423             if (t == cause)
424             {
425                 break;
426             }
427         }
428         return exceptions;
429     }
430 
431     public static Map getExceptionInfo(Throwable t)
432     {
433         Map info = new HashMap();
434         Throwable cause = t;
435         while (cause != null)
436         {
437             info.putAll(getExceptionReader(cause).getInfo(cause));
438             cause = getExceptionReader(cause).getCause(cause);
439             // address some misbehaving exceptions, avoid endless loop
440             if (t == cause)
441             {
442                 break;
443             }
444         }
445         return info;
446     }
447 
448     public static String getExceptionStack(Throwable t)
449     {
450         StringBuffer buf = new StringBuffer();
451         // get exception stack
452         List exceptions = getExceptionsAsList(t);
453 
454         int i = 1;
455         for (Iterator iterator = exceptions.iterator(); iterator.hasNext(); i++)
456         {
457             if (i > exceptionThreshold && exceptionThreshold > 0)
458             {
459                 buf.append("(").append(exceptions.size() - i + 1).append(" more...)");
460                 break;
461             }
462             Throwable throwable = (Throwable) iterator.next();
463             ExceptionReader er = getExceptionReader(throwable);
464             buf.append(i).append(". ").append(er.getMessage(throwable)).append(" (");
465             buf.append(throwable.getClass().getName()).append(")\n");
466             if (verbose && throwable.getStackTrace().length > 0)
467             {
468                 StackTraceElement e = throwable.getStackTrace()[0];
469                 buf.append("  ")
470                     .append(e.getClassName())
471                     .append(":")
472                     .append(e.getLineNumber())
473                     .append(" (")
474                     .append(getJavaDocUrl(throwable.getClass()))
475                     .append(")\n");
476             }
477         }
478         return buf.toString();
479     }
480 
481     /**
482      * Registers an exception reader with Mule
483      *
484      * @param reader the reader to register.
485      */
486     public static void registerExceptionReader(ExceptionReader reader)
487     {
488         exceptionReaders.add(reader);
489     }
490 
491     /**
492      * Gets an exception reader for the exception
493      *
494      * @param t the exception to get a reader for
495      * @return either a specific reader or an instance of DefaultExceptionReader.
496      *         This method never returns null;
497      */
498     public static ExceptionReader getExceptionReader(Throwable t)
499     {
500         for (Iterator iterator = exceptionReaders.iterator(); iterator.hasNext();)
501         {
502             ExceptionReader exceptionReader = (ExceptionReader) iterator.next();
503             if (exceptionReader.getExceptionType().isInstance(t))
504             {
505                 return exceptionReader;
506             }
507         }
508         return defaultExceptionReader;
509     }
510 
511     public static String writeException(Throwable t)
512     {
513         ExceptionReader er = getExceptionReader(t);
514         StringBuffer msg = new StringBuffer();
515         msg.append(er.getMessage(t)).append(". Type: ").append(t.getClass());
516         return msg.toString();
517     }
518 }