Coverage Report - org.apache.commons.lang3.exception.ExceptionUtils
 
Classes in this File Line Coverage Branch Coverage Complexity
ExceptionUtils
89%
128/143
93%
80/86
3,52
 
 1  
 /*
 2  
  * Licensed to the Apache Software Foundation (ASF) under one or more
 3  
  * contributor license agreements.  See the NOTICE file distributed with
 4  
  * this work for additional information regarding copyright ownership.
 5  
  * The ASF licenses this file to You under the Apache License, Version 2.0
 6  
  * (the "License"); you may not use this file except in compliance with
 7  
  * the License.  You may obtain a copy of the License at
 8  
  * 
 9  
  *      http://www.apache.org/licenses/LICENSE-2.0
 10  
  * 
 11  
  * Unless required by applicable law or agreed to in writing, software
 12  
  * distributed under the License is distributed on an "AS IS" BASIS,
 13  
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 14  
  * See the License for the specific language governing permissions and
 15  
  * limitations under the License.
 16  
  */
 17  
 package org.apache.commons.lang3.exception;
 18  
 
 19  
 import java.io.PrintStream;
 20  
 import java.io.PrintWriter;
 21  
 import java.io.StringWriter;
 22  
 import java.lang.reflect.InvocationTargetException;
 23  
 import java.lang.reflect.Method;
 24  
 import java.util.ArrayList;
 25  
 import java.util.List;
 26  
 import java.util.StringTokenizer;
 27  
 
 28  
 import org.apache.commons.lang3.ArrayUtils;
 29  
 import org.apache.commons.lang3.ClassUtils;
 30  
 import org.apache.commons.lang3.StringUtils;
 31  
 import org.apache.commons.lang3.SystemUtils;
 32  
 
 33  
 /**
 34  
  * <p>Provides utilities for manipulating and examining 
 35  
  * <code>Throwable</code> objects.</p>
 36  
  *
 37  
  * @since 1.0
 38  
  */
 39  
 public class ExceptionUtils {
 40  
     
 41  
     /**
 42  
      * <p>Used when printing stack frames to denote the start of a
 43  
      * wrapped exception.</p>
 44  
      *
 45  
      * <p>Package private for accessibility by test suite.</p>
 46  
      */
 47  
     static final String WRAPPED_MARKER = " [wrapped] ";
 48  
 
 49  
     /**
 50  
      * <p>The names of methods commonly used to access a wrapped exception.</p>
 51  
      */
 52  
     // TODO: Remove in Lang 4.0
 53  1
     private static final String[] CAUSE_METHOD_NAMES = {
 54  
         "getCause",
 55  
         "getNextException",
 56  
         "getTargetException",
 57  
         "getException",
 58  
         "getSourceException",
 59  
         "getRootCause",
 60  
         "getCausedByException",
 61  
         "getNested",
 62  
         "getLinkedException",
 63  
         "getNestedException",
 64  
         "getLinkedCause",
 65  
         "getThrowable",
 66  
     };
 67  
 
 68  
     /**
 69  
      * <p>
 70  
      * Public constructor allows an instance of <code>ExceptionUtils</code> to be created, although that is not
 71  
      * normally necessary.
 72  
      * </p>
 73  
      */
 74  
     public ExceptionUtils() {
 75  1
         super();
 76  1
     }
 77  
 
 78  
     //-----------------------------------------------------------------------
 79  
     /**
 80  
      * <p>Returns the default names used when searching for the cause of an exception.</p>
 81  
      *
 82  
      * <p>This may be modified and used in the overloaded getCause(Throwable, String[]) method.</p>
 83  
      *
 84  
      * @return cloned array of the default method names
 85  
      * @since 3.0
 86  
      * @deprecated This feature will be removed in Lang 4.0
 87  
      */
 88  
     @Deprecated
 89  
     public static String[] getDefaultCauseMethodNames() {
 90  0
         return ArrayUtils.clone(CAUSE_METHOD_NAMES);
 91  
     }
 92  
 
 93  
     //-----------------------------------------------------------------------
 94  
     /**
 95  
      * <p>Introspects the <code>Throwable</code> to obtain the cause.</p>
 96  
      *
 97  
      * <p>The method searches for methods with specific names that return a 
 98  
      * <code>Throwable</code> object. This will pick up most wrapping exceptions,
 99  
      * including those from JDK 1.4.
 100  
      *
 101  
      * <p>The default list searched for are:</p>
 102  
      * <ul>
 103  
      *  <li><code>getCause()</code></li>
 104  
      *  <li><code>getNextException()</code></li>
 105  
      *  <li><code>getTargetException()</code></li>
 106  
      *  <li><code>getException()</code></li>
 107  
      *  <li><code>getSourceException()</code></li>
 108  
      *  <li><code>getRootCause()</code></li>
 109  
      *  <li><code>getCausedByException()</code></li>
 110  
      *  <li><code>getNested()</code></li>
 111  
      * </ul>
 112  
      * 
 113  
      * <p>If none of the above is found, returns <code>null</code>.</p>
 114  
      *
 115  
      * @param throwable  the throwable to introspect for a cause, may be null
 116  
      * @return the cause of the <code>Throwable</code>,
 117  
      *  <code>null</code> if none found or null throwable input
 118  
      * @since 1.0
 119  
      * @deprecated This feature will be removed in Lang 4.0
 120  
      */
 121  
     @Deprecated
 122  
     public static Throwable getCause(final Throwable throwable) {
 123  171
         return getCause(throwable, CAUSE_METHOD_NAMES);
 124  
     }
 125  
 
 126  
     /**
 127  
      * <p>Introspects the <code>Throwable</code> to obtain the cause.</p>
 128  
      *
 129  
      * <p>A <code>null</code> set of method names means use the default set.
 130  
      * A <code>null</code> in the set of method names will be ignored.</p>
 131  
      *
 132  
      * @param throwable  the throwable to introspect for a cause, may be null
 133  
      * @param methodNames  the method names, null treated as default set
 134  
      * @return the cause of the <code>Throwable</code>,
 135  
      *  <code>null</code> if none found or null throwable input
 136  
      * @since 1.0
 137  
      * @deprecated This feature will be removed in Lang 4.0
 138  
      */
 139  
     @Deprecated
 140  
     public static Throwable getCause(final Throwable throwable, String[] methodNames) {
 141  182
         if (throwable == null) {
 142  3
             return null;
 143  
         }
 144  
 
 145  179
         if (methodNames == null) {
 146  2
             methodNames = CAUSE_METHOD_NAMES;
 147  
         }
 148  
 
 149  1083
         for (final String methodName : methodNames) {
 150  1002
             if (methodName != null) {
 151  1000
                 final Throwable cause = getCauseUsingMethodName(throwable, methodName);
 152  1000
                 if (cause != null) {
 153  98
                     return cause;
 154  
                 }
 155  
             }
 156  
         }
 157  
 
 158  81
         return null;
 159  
     }
 160  
 
 161  
     /**
 162  
      * <p>Introspects the <code>Throwable</code> to obtain the root cause.</p>
 163  
      *
 164  
      * <p>This method walks through the exception chain to the last element,
 165  
      * "root" of the tree, using {@link #getCause(Throwable)}, and
 166  
      * returns that exception.</p>
 167  
      *
 168  
      * <p>From version 2.2, this method handles recursive cause structures
 169  
      * that might otherwise cause infinite loops. If the throwable parameter
 170  
      * has a cause of itself, then null will be returned. If the throwable
 171  
      * parameter cause chain loops, the last element in the chain before the
 172  
      * loop is returned.</p>
 173  
      *
 174  
      * @param throwable  the throwable to get the root cause for, may be null
 175  
      * @return the root cause of the <code>Throwable</code>,
 176  
      *  <code>null</code> if none found or null throwable input
 177  
      */
 178  
     public static Throwable getRootCause(final Throwable throwable) {
 179  9
         final List<Throwable> list = getThrowableList(throwable);
 180  9
         return list.size() < 2 ? null : (Throwable)list.get(list.size() - 1);
 181  
     }
 182  
 
 183  
     /**
 184  
      * <p>Finds a <code>Throwable</code> by method name.</p>
 185  
      *
 186  
      * @param throwable  the exception to examine
 187  
      * @param methodName  the name of the method to find and invoke
 188  
      * @return the wrapped exception, or <code>null</code> if not found
 189  
      */
 190  
     // TODO: Remove in Lang 4.0
 191  
     private static Throwable getCauseUsingMethodName(final Throwable throwable, final String methodName) {
 192  1000
         Method method = null;
 193  
         try {
 194  1000
             method = throwable.getClass().getMethod(methodName);
 195  757
         } catch (final NoSuchMethodException ignored) { // NOPMD
 196  
             // exception ignored
 197  0
         } catch (final SecurityException ignored) { // NOPMD
 198  
             // exception ignored
 199  1000
         }
 200  
 
 201  1000
         if (method != null && Throwable.class.isAssignableFrom(method.getReturnType())) {
 202  
             try {
 203  174
                 return (Throwable) method.invoke(throwable);
 204  0
             } catch (final IllegalAccessException ignored) { // NOPMD
 205  
                 // exception ignored
 206  0
             } catch (final IllegalArgumentException ignored) { // NOPMD
 207  
                 // exception ignored
 208  0
             } catch (final InvocationTargetException ignored) { // NOPMD
 209  
                 // exception ignored
 210  0
             }
 211  
         }
 212  826
         return null;
 213  
     }
 214  
 
 215  
     //-----------------------------------------------------------------------
 216  
     /**
 217  
      * <p>Counts the number of <code>Throwable</code> objects in the
 218  
      * exception chain.</p>
 219  
      *
 220  
      * <p>A throwable without cause will return <code>1</code>.
 221  
      * A throwable with one cause will return <code>2</code> and so on.
 222  
      * A <code>null</code> throwable will return <code>0</code>.</p>
 223  
      *
 224  
      * <p>From version 2.2, this method handles recursive cause structures
 225  
      * that might otherwise cause infinite loops. The cause chain is
 226  
      * processed until the end is reached, or until the next item in the
 227  
      * chain is already in the result set.</p>
 228  
      *
 229  
      * @param throwable  the throwable to inspect, may be null
 230  
      * @return the count of throwables, zero if null input
 231  
      */
 232  
     public static int getThrowableCount(final Throwable throwable) {
 233  6
         return getThrowableList(throwable).size();
 234  
     }
 235  
 
 236  
     /**
 237  
      * <p>Returns the list of <code>Throwable</code> objects in the
 238  
      * exception chain.</p>
 239  
      *
 240  
      * <p>A throwable without cause will return an array containing
 241  
      * one element - the input throwable.
 242  
      * A throwable with one cause will return an array containing
 243  
      * two elements. - the input throwable and the cause throwable.
 244  
      * A <code>null</code> throwable will return an array of size zero.</p>
 245  
      *
 246  
      * <p>From version 2.2, this method handles recursive cause structures
 247  
      * that might otherwise cause infinite loops. The cause chain is
 248  
      * processed until the end is reached, or until the next item in the
 249  
      * chain is already in the result set.</p>
 250  
      *
 251  
      * @see #getThrowableList(Throwable)
 252  
      * @param throwable  the throwable to inspect, may be null
 253  
      * @return the array of throwables, never null
 254  
      */
 255  
     public static Throwable[] getThrowables(final Throwable throwable) {
 256  60
         final List<Throwable> list = getThrowableList(throwable);
 257  60
         return list.toArray(new Throwable[list.size()]);
 258  
     }
 259  
 
 260  
     /**
 261  
      * <p>Returns the list of <code>Throwable</code> objects in the
 262  
      * exception chain.</p>
 263  
      *
 264  
      * <p>A throwable without cause will return a list containing
 265  
      * one element - the input throwable.
 266  
      * A throwable with one cause will return a list containing
 267  
      * two elements. - the input throwable and the cause throwable.
 268  
      * A <code>null</code> throwable will return a list of size zero.</p>
 269  
      *
 270  
      * <p>This method handles recursive cause structures that might
 271  
      * otherwise cause infinite loops. The cause chain is processed until
 272  
      * the end is reached, or until the next item in the chain is already
 273  
      * in the result set.</p>
 274  
      *
 275  
      * @param throwable  the throwable to inspect, may be null
 276  
      * @return the list of throwables, never null
 277  
      * @since Commons Lang 2.2
 278  
      */
 279  
     public static List<Throwable> getThrowableList(Throwable throwable) {
 280  81
         final List<Throwable> list = new ArrayList<Throwable>();
 281  244
         while (throwable != null && list.contains(throwable) == false) {
 282  163
             list.add(throwable);
 283  163
             throwable = ExceptionUtils.getCause(throwable);
 284  
         }
 285  81
         return list;
 286  
     }
 287  
 
 288  
     //-----------------------------------------------------------------------
 289  
     /**
 290  
      * <p>Returns the (zero based) index of the first <code>Throwable</code>
 291  
      * that matches the specified class (exactly) in the exception chain.
 292  
      * Subclasses of the specified class do not match - see
 293  
      * {@link #indexOfType(Throwable, Class)} for the opposite.</p>
 294  
      *
 295  
      * <p>A <code>null</code> throwable returns <code>-1</code>.
 296  
      * A <code>null</code> type returns <code>-1</code>.
 297  
      * No match in the chain returns <code>-1</code>.</p>
 298  
      *
 299  
      * @param throwable  the throwable to inspect, may be null
 300  
      * @param clazz  the class to search for, subclasses do not match, null returns -1
 301  
      * @return the index into the throwable chain, -1 if no match or null input
 302  
      */
 303  
     public static int indexOfThrowable(final Throwable throwable, final Class<?> clazz) {
 304  17
         return indexOf(throwable, clazz, 0, false);
 305  
     }
 306  
 
 307  
     /**
 308  
      * <p>Returns the (zero based) index of the first <code>Throwable</code>
 309  
      * that matches the specified type in the exception chain from
 310  
      * a specified index.
 311  
      * Subclasses of the specified class do not match - see
 312  
      * {@link #indexOfType(Throwable, Class, int)} for the opposite.</p>
 313  
      *
 314  
      * <p>A <code>null</code> throwable returns <code>-1</code>.
 315  
      * A <code>null</code> type returns <code>-1</code>.
 316  
      * No match in the chain returns <code>-1</code>.
 317  
      * A negative start index is treated as zero.
 318  
      * A start index greater than the number of throwables returns <code>-1</code>.</p>
 319  
      *
 320  
      * @param throwable  the throwable to inspect, may be null
 321  
      * @param clazz  the class to search for, subclasses do not match, null returns -1
 322  
      * @param fromIndex  the (zero based) index of the starting position,
 323  
      *  negative treated as zero, larger than chain size returns -1
 324  
      * @return the index into the throwable chain, -1 if no match or null input
 325  
      */
 326  
     public static int indexOfThrowable(final Throwable throwable, final Class<?> clazz, final int fromIndex) {
 327  17
         return indexOf(throwable, clazz, fromIndex, false);
 328  
     }
 329  
 
 330  
     //-----------------------------------------------------------------------
 331  
     /**
 332  
      * <p>Returns the (zero based) index of the first <code>Throwable</code>
 333  
      * that matches the specified class or subclass in the exception chain.
 334  
      * Subclasses of the specified class do match - see
 335  
      * {@link #indexOfThrowable(Throwable, Class)} for the opposite.</p>
 336  
      *
 337  
      * <p>A <code>null</code> throwable returns <code>-1</code>.
 338  
      * A <code>null</code> type returns <code>-1</code>.
 339  
      * No match in the chain returns <code>-1</code>.</p>
 340  
      *
 341  
      * @param throwable  the throwable to inspect, may be null
 342  
      * @param type  the type to search for, subclasses match, null returns -1
 343  
      * @return the index into the throwable chain, -1 if no match or null input
 344  
      * @since 2.1
 345  
      */
 346  
     public static int indexOfType(final Throwable throwable, final Class<?> type) {
 347  17
         return indexOf(throwable, type, 0, true);
 348  
     }
 349  
 
 350  
     /**
 351  
      * <p>Returns the (zero based) index of the first <code>Throwable</code>
 352  
      * that matches the specified type in the exception chain from
 353  
      * a specified index.
 354  
      * Subclasses of the specified class do match - see
 355  
      * {@link #indexOfThrowable(Throwable, Class)} for the opposite.</p>
 356  
      *
 357  
      * <p>A <code>null</code> throwable returns <code>-1</code>.
 358  
      * A <code>null</code> type returns <code>-1</code>.
 359  
      * No match in the chain returns <code>-1</code>.
 360  
      * A negative start index is treated as zero.
 361  
      * A start index greater than the number of throwables returns <code>-1</code>.</p>
 362  
      *
 363  
      * @param throwable  the throwable to inspect, may be null
 364  
      * @param type  the type to search for, subclasses match, null returns -1
 365  
      * @param fromIndex  the (zero based) index of the starting position,
 366  
      *  negative treated as zero, larger than chain size returns -1
 367  
      * @return the index into the throwable chain, -1 if no match or null input
 368  
      * @since 2.1
 369  
      */
 370  
     public static int indexOfType(final Throwable throwable, final Class<?> type, final int fromIndex) {
 371  17
         return indexOf(throwable, type, fromIndex, true);
 372  
     }
 373  
 
 374  
     /**
 375  
      * <p>Worker method for the <code>indexOfType</code> methods.</p>
 376  
      *
 377  
      * @param throwable  the throwable to inspect, may be null
 378  
      * @param type  the type to search for, subclasses match, null returns -1
 379  
      * @param fromIndex  the (zero based) index of the starting position,
 380  
      *  negative treated as zero, larger than chain size returns -1
 381  
      * @param subclass if <code>true</code>, compares with {@link Class#isAssignableFrom(Class)}, otherwise compares
 382  
      * using references
 383  
      * @return index of the <code>type</code> within throwables nested within the specified <code>throwable</code>
 384  
      */
 385  
     private static int indexOf(final Throwable throwable, final Class<?> type, int fromIndex, final boolean subclass) {
 386  68
         if (throwable == null || type == null) {
 387  20
             return -1;
 388  
         }
 389  48
         if (fromIndex < 0) {
 390  2
             fromIndex = 0;
 391  
         }
 392  48
         final Throwable[] throwables = ExceptionUtils.getThrowables(throwable);
 393  48
         if (fromIndex >= throwables.length) {
 394  2
             return -1;
 395  
         }
 396  46
         if (subclass) {
 397  41
             for (int i = fromIndex; i < throwables.length; i++) {
 398  34
                 if (type.isAssignableFrom(throwables[i].getClass())) {
 399  16
                     return i;
 400  
                 }
 401  
             }
 402  
         } else {
 403  47
             for (int i = fromIndex; i < throwables.length; i++) {
 404  38
                 if (type.equals(throwables[i].getClass())) {
 405  14
                     return i;
 406  
                 }
 407  
             }
 408  
         }
 409  16
         return -1;
 410  
     }
 411  
 
 412  
     //-----------------------------------------------------------------------
 413  
     /**
 414  
      * <p>Prints a compact stack trace for the root cause of a throwable
 415  
      * to <code>System.err</code>.</p>
 416  
      *
 417  
      * <p>The compact stack trace starts with the root cause and prints
 418  
      * stack frames up to the place where it was caught and wrapped.
 419  
      * Then it prints the wrapped exception and continues with stack frames
 420  
      * until the wrapper exception is caught and wrapped again, etc.</p>
 421  
      *
 422  
      * <p>The output of this method is consistent across JDK versions.
 423  
      * Note that this is the opposite order to the JDK1.4 display.</p>
 424  
      *
 425  
      * <p>The method is equivalent to <code>printStackTrace</code> for throwables
 426  
      * that don't have nested causes.</p>
 427  
      *
 428  
      * @param throwable  the throwable to output
 429  
      * @since 2.0
 430  
      */
 431  
     public static void printRootCauseStackTrace(final Throwable throwable) {
 432  1
         printRootCauseStackTrace(throwable, System.err);
 433  1
     }
 434  
 
 435  
     /**
 436  
      * <p>Prints a compact stack trace for the root cause of a throwable.</p>
 437  
      *
 438  
      * <p>The compact stack trace starts with the root cause and prints
 439  
      * stack frames up to the place where it was caught and wrapped.
 440  
      * Then it prints the wrapped exception and continues with stack frames
 441  
      * until the wrapper exception is caught and wrapped again, etc.</p>
 442  
      *
 443  
      * <p>The output of this method is consistent across JDK versions.
 444  
      * Note that this is the opposite order to the JDK1.4 display.</p>
 445  
      *
 446  
      * <p>The method is equivalent to <code>printStackTrace</code> for throwables
 447  
      * that don't have nested causes.</p>
 448  
      *
 449  
      * @param throwable  the throwable to output, may be null
 450  
      * @param stream  the stream to output to, may not be null
 451  
      * @throws IllegalArgumentException if the stream is <code>null</code>
 452  
      * @since 2.0
 453  
      */
 454  
     public static void printRootCauseStackTrace(final Throwable throwable, final PrintStream stream) {
 455  6
         if (throwable == null) {
 456  3
             return;
 457  
         }
 458  3
         if (stream == null) {
 459  1
             throw new IllegalArgumentException("The PrintStream must not be null");
 460  
         }
 461  2
         final String trace[] = getRootCauseStackTrace(throwable);
 462  63
         for (final String element : trace) {
 463  61
             stream.println(element);
 464  
         }
 465  2
         stream.flush();
 466  2
     }
 467  
 
 468  
     /**
 469  
      * <p>Prints a compact stack trace for the root cause of a throwable.</p>
 470  
      *
 471  
      * <p>The compact stack trace starts with the root cause and prints
 472  
      * stack frames up to the place where it was caught and wrapped.
 473  
      * Then it prints the wrapped exception and continues with stack frames
 474  
      * until the wrapper exception is caught and wrapped again, etc.</p>
 475  
      *
 476  
      * <p>The output of this method is consistent across JDK versions.
 477  
      * Note that this is the opposite order to the JDK1.4 display.</p>
 478  
      *
 479  
      * <p>The method is equivalent to <code>printStackTrace</code> for throwables
 480  
      * that don't have nested causes.</p>
 481  
      *
 482  
      * @param throwable  the throwable to output, may be null
 483  
      * @param writer  the writer to output to, may not be null
 484  
      * @throws IllegalArgumentException if the writer is <code>null</code>
 485  
      * @since 2.0
 486  
      */
 487  
     public static void printRootCauseStackTrace(final Throwable throwable, final PrintWriter writer) {
 488  5
         if (throwable == null) {
 489  2
             return;
 490  
         }
 491  3
         if (writer == null) {
 492  1
             throw new IllegalArgumentException("The PrintWriter must not be null");
 493  
         }
 494  2
         final String trace[] = getRootCauseStackTrace(throwable);
 495  63
         for (final String element : trace) {
 496  61
             writer.println(element);
 497  
         }
 498  2
         writer.flush();
 499  2
     }
 500  
 
 501  
     //-----------------------------------------------------------------------
 502  
     /**
 503  
      * <p>Creates a compact stack trace for the root cause of the supplied
 504  
      * <code>Throwable</code>.</p>
 505  
      *
 506  
      * <p>The output of this method is consistent across JDK versions.
 507  
      * It consists of the root exception followed by each of its wrapping
 508  
      * exceptions separated by '[wrapped]'. Note that this is the opposite
 509  
      * order to the JDK1.4 display.</p>
 510  
      *
 511  
      * @param throwable  the throwable to examine, may be null
 512  
      * @return an array of stack trace frames, never null
 513  
      * @since 2.0
 514  
      */
 515  
     public static String[] getRootCauseStackTrace(final Throwable throwable) {
 516  7
         if (throwable == null) {
 517  1
             return ArrayUtils.EMPTY_STRING_ARRAY;
 518  
         }
 519  6
         final Throwable throwables[] = getThrowables(throwable);
 520  6
         final int count = throwables.length;
 521  6
         final List<String> frames = new ArrayList<String>();
 522  6
         List<String> nextTrace = getStackFrameList(throwables[count - 1]);
 523  6
         for (int i = count; --i >= 0;) {
 524  12
             final List<String> trace = nextTrace;
 525  12
             if (i != 0) {
 526  6
                 nextTrace = getStackFrameList(throwables[i - 1]);
 527  6
                 removeCommonFrames(trace, nextTrace);
 528  
             }
 529  12
             if (i == count - 1) {
 530  6
                 frames.add(throwables[i].toString());
 531  
             } else {
 532  6
                 frames.add(WRAPPED_MARKER + throwables[i].toString());
 533  
             }
 534  182
             for (int j = 0; j < trace.size(); j++) {
 535  170
                 frames.add(trace.get(j));
 536  
             }
 537  12
         }
 538  6
         return frames.toArray(new String[frames.size()]);
 539  
     }
 540  
 
 541  
     /**
 542  
      * <p>Removes common frames from the cause trace given the two stack traces.</p>
 543  
      *
 544  
      * @param causeFrames  stack trace of a cause throwable
 545  
      * @param wrapperFrames  stack trace of a wrapper throwable
 546  
      * @throws IllegalArgumentException if either argument is null
 547  
      * @since 2.0
 548  
      */
 549  
     public static void removeCommonFrames(final List<String> causeFrames, final List<String> wrapperFrames) {
 550  7
         if (causeFrames == null || wrapperFrames == null) {
 551  1
             throw new IllegalArgumentException("The List must not be null");
 552  
         }
 553  6
         int causeFrameIndex = causeFrames.size() - 1;
 554  6
         int wrapperFrameIndex = wrapperFrames.size() - 1;
 555  174
         while (causeFrameIndex >= 0 && wrapperFrameIndex >= 0) {
 556  
             // Remove the frame from the cause trace if it is the same
 557  
             // as in the wrapper trace
 558  168
             final String causeFrame = causeFrames.get(causeFrameIndex);
 559  168
             final String wrapperFrame = wrapperFrames.get(wrapperFrameIndex);
 560  168
             if (causeFrame.equals(wrapperFrame)) {
 561  165
                 causeFrames.remove(causeFrameIndex);
 562  
             }
 563  168
             causeFrameIndex--;
 564  168
             wrapperFrameIndex--;
 565  168
         }
 566  6
     }
 567  
 
 568  
     //-----------------------------------------------------------------------
 569  
     /**
 570  
      * <p>Gets the stack trace from a Throwable as a String.</p>
 571  
      *
 572  
      * <p>The result of this method vary by JDK version as this method
 573  
      * uses {@link Throwable#printStackTrace(java.io.PrintWriter)}.
 574  
      * On JDK1.3 and earlier, the cause exception will not be shown
 575  
      * unless the specified throwable alters printStackTrace.</p>
 576  
      *
 577  
      * @param throwable  the <code>Throwable</code> to be examined
 578  
      * @return the stack trace as generated by the exception's
 579  
      *  <code>printStackTrace(PrintWriter)</code> method
 580  
      */
 581  
     public static String getStackTrace(final Throwable throwable) {
 582  33
         final StringWriter sw = new StringWriter();
 583  33
         final PrintWriter pw = new PrintWriter(sw, true);
 584  33
         throwable.printStackTrace(pw);
 585  33
         return sw.getBuffer().toString();
 586  
     }
 587  
 
 588  
     /**
 589  
      * <p>Captures the stack trace associated with the specified
 590  
      * <code>Throwable</code> object, decomposing it into a list of
 591  
      * stack frames.</p>
 592  
      *
 593  
      * <p>The result of this method vary by JDK version as this method
 594  
      * uses {@link Throwable#printStackTrace(java.io.PrintWriter)}.
 595  
      * On JDK1.3 and earlier, the cause exception will not be shown
 596  
      * unless the specified throwable alters printStackTrace.</p>
 597  
      *
 598  
      * @param throwable  the <code>Throwable</code> to examine, may be null
 599  
      * @return an array of strings describing each stack frame, never null
 600  
      */
 601  
     public static String[] getStackFrames(final Throwable throwable) {
 602  0
         if (throwable == null) {
 603  0
             return ArrayUtils.EMPTY_STRING_ARRAY;
 604  
         }
 605  0
         return getStackFrames(getStackTrace(throwable));
 606  
     }
 607  
 
 608  
     //-----------------------------------------------------------------------
 609  
     /**
 610  
      * <p>Returns an array where each element is a line from the argument.</p>
 611  
      *
 612  
      * <p>The end of line is determined by the value of {@link SystemUtils#LINE_SEPARATOR}.</p>
 613  
      *
 614  
      * @param stackTrace  a stack trace String
 615  
      * @return an array where each element is a line from the argument
 616  
      */
 617  
     static String[] getStackFrames(final String stackTrace) {
 618  0
         final String linebreak = SystemUtils.LINE_SEPARATOR;
 619  0
         final StringTokenizer frames = new StringTokenizer(stackTrace, linebreak);
 620  0
         final List<String> list = new ArrayList<String>();
 621  0
         while (frames.hasMoreTokens()) {
 622  0
             list.add(frames.nextToken());
 623  
         }
 624  0
         return list.toArray(new String[list.size()]);
 625  
     }
 626  
 
 627  
     /**
 628  
      * <p>Produces a <code>List</code> of stack frames - the message
 629  
      * is not included. Only the trace of the specified exception is
 630  
      * returned, any caused by trace is stripped.</p>
 631  
      *
 632  
      * <p>This works in most cases - it will only fail if the exception
 633  
      * message contains a line that starts with:
 634  
      * <code>&quot;&nbsp;&nbsp;&nbsp;at&quot;.</code></p>
 635  
      * 
 636  
      * @param t is any throwable
 637  
      * @return List of stack frames
 638  
      */
 639  
     static List<String> getStackFrameList(final Throwable t) {
 640  12
         final String stackTrace = getStackTrace(t);
 641  12
         final String linebreak = SystemUtils.LINE_SEPARATOR;
 642  12
         final StringTokenizer frames = new StringTokenizer(stackTrace, linebreak);
 643  12
         final List<String> list = new ArrayList<String>();
 644  12
         boolean traceStarted = false;
 645  359
         while (frames.hasMoreTokens()) {
 646  353
             final String token = frames.nextToken();
 647  
             // Determine if the line starts with <whitespace>at
 648  353
             final int at = token.indexOf("at");
 649  353
             if (at != -1 && token.substring(0, at).trim().isEmpty()) {
 650  335
                 traceStarted = true;
 651  335
                 list.add(token);
 652  18
             } else if (traceStarted) {
 653  6
                 break;
 654  
             }
 655  347
         }
 656  12
         return list;
 657  
     }
 658  
 
 659  
     //-----------------------------------------------------------------------
 660  
     /**
 661  
      * Gets a short message summarising the exception.
 662  
      * <p>
 663  
      * The message returned is of the form
 664  
      * {ClassNameWithoutPackage}: {ThrowableMessage}
 665  
      *
 666  
      * @param th  the throwable to get a message for, null returns empty string
 667  
      * @return the message, non-null
 668  
      * @since Commons Lang 2.2
 669  
      */
 670  
     public static String getMessage(final Throwable th) {
 671  6
         if (th == null) {
 672  2
             return "";
 673  
         }
 674  4
         final String clsName = ClassUtils.getShortClassName(th, null);
 675  4
         final String msg = th.getMessage();
 676  4
         return clsName + ": " + StringUtils.defaultString(msg);
 677  
     }
 678  
 
 679  
     //-----------------------------------------------------------------------
 680  
     /**
 681  
      * Gets a short message summarising the root cause exception.
 682  
      * <p>
 683  
      * The message returned is of the form
 684  
      * {ClassNameWithoutPackage}: {ThrowableMessage}
 685  
      *
 686  
      * @param th  the throwable to get a message for, null returns empty string
 687  
      * @return the message, non-null
 688  
      * @since Commons Lang 2.2
 689  
      */
 690  
     public static String getRootCauseMessage(final Throwable th) {
 691  3
         Throwable root = ExceptionUtils.getRootCause(th);
 692  3
         root = root == null ? th : root;
 693  3
         return getMessage(root);
 694  
     }
 695  
 
 696  
 }