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  
  * @version $Id: ExceptionUtils.java 1436770 2013-01-22 07:09:45Z ggregory $
 39  
  */
 40  
 public class ExceptionUtils {
 41  
     
 42  
     /**
 43  
      * <p>Used when printing stack frames to denote the start of a
 44  
      * wrapped exception.</p>
 45  
      *
 46  
      * <p>Package private for accessibility by test suite.</p>
 47  
      */
 48  
     static final String WRAPPED_MARKER = " [wrapped] ";
 49  
 
 50  
     /**
 51  
      * <p>The names of methods commonly used to access a wrapped exception.</p>
 52  
      */
 53  
     // TODO: Remove in Lang 4.0
 54  1
     private static final String[] CAUSE_METHOD_NAMES = {
 55  
         "getCause",
 56  
         "getNextException",
 57  
         "getTargetException",
 58  
         "getException",
 59  
         "getSourceException",
 60  
         "getRootCause",
 61  
         "getCausedByException",
 62  
         "getNested",
 63  
         "getLinkedException",
 64  
         "getNestedException",
 65  
         "getLinkedCause",
 66  
         "getThrowable",
 67  
     };
 68  
 
 69  
     /**
 70  
      * <p>
 71  
      * Public constructor allows an instance of <code>ExceptionUtils</code> to be created, although that is not
 72  
      * normally necessary.
 73  
      * </p>
 74  
      */
 75  
     public ExceptionUtils() {
 76  1
         super();
 77  1
     }
 78  
 
 79  
     //-----------------------------------------------------------------------
 80  
     /**
 81  
      * <p>Returns the default names used when searching for the cause of an exception.</p>
 82  
      *
 83  
      * <p>This may be modified and used in the overloaded getCause(Throwable, String[]) method.</p>
 84  
      *
 85  
      * @return cloned array of the default method names
 86  
      * @since 3.0
 87  
      * @deprecated This feature will be removed in Lang 4.0
 88  
      */
 89  
     @Deprecated
 90  
     public static String[] getDefaultCauseMethodNames() {
 91  0
         return ArrayUtils.clone(CAUSE_METHOD_NAMES);
 92  
     }
 93  
 
 94  
     //-----------------------------------------------------------------------
 95  
     /**
 96  
      * <p>Introspects the <code>Throwable</code> to obtain the cause.</p>
 97  
      *
 98  
      * <p>The method searches for methods with specific names that return a 
 99  
      * <code>Throwable</code> object. This will pick up most wrapping exceptions,
 100  
      * including those from JDK 1.4.
 101  
      *
 102  
      * <p>The default list searched for are:</p>
 103  
      * <ul>
 104  
      *  <li><code>getCause()</code></li>
 105  
      *  <li><code>getNextException()</code></li>
 106  
      *  <li><code>getTargetException()</code></li>
 107  
      *  <li><code>getException()</code></li>
 108  
      *  <li><code>getSourceException()</code></li>
 109  
      *  <li><code>getRootCause()</code></li>
 110  
      *  <li><code>getCausedByException()</code></li>
 111  
      *  <li><code>getNested()</code></li>
 112  
      * </ul>
 113  
      * 
 114  
      * <p>If none of the above is found, returns <code>null</code>.</p>
 115  
      *
 116  
      * @param throwable  the throwable to introspect for a cause, may be null
 117  
      * @return the cause of the <code>Throwable</code>,
 118  
      *  <code>null</code> if none found or null throwable input
 119  
      * @since 1.0
 120  
      * @deprecated This feature will be removed in Lang 4.0
 121  
      */
 122  
     @Deprecated
 123  
     public static Throwable getCause(final Throwable throwable) {
 124  171
         return getCause(throwable, CAUSE_METHOD_NAMES);
 125  
     }
 126  
 
 127  
     /**
 128  
      * <p>Introspects the <code>Throwable</code> to obtain the cause.</p>
 129  
      *
 130  
      * <p>A <code>null</code> set of method names means use the default set.
 131  
      * A <code>null</code> in the set of method names will be ignored.</p>
 132  
      *
 133  
      * @param throwable  the throwable to introspect for a cause, may be null
 134  
      * @param methodNames  the method names, null treated as default set
 135  
      * @return the cause of the <code>Throwable</code>,
 136  
      *  <code>null</code> if none found or null throwable input
 137  
      * @since 1.0
 138  
      * @deprecated This feature will be removed in Lang 4.0
 139  
      */
 140  
     @Deprecated
 141  
     public static Throwable getCause(final Throwable throwable, String[] methodNames) {
 142  182
         if (throwable == null) {
 143  3
             return null;
 144  
         }
 145  
 
 146  179
         if (methodNames == null) {
 147  2
             methodNames = CAUSE_METHOD_NAMES;
 148  
         }
 149  
 
 150  1083
         for (final String methodName : methodNames) {
 151  1002
             if (methodName != null) {
 152  1000
                 final Throwable cause = getCauseUsingMethodName(throwable, methodName);
 153  1000
                 if (cause != null) {
 154  98
                     return cause;
 155  
                 }
 156  
             }
 157  
         }
 158  
 
 159  81
         return null;
 160  
     }
 161  
 
 162  
     /**
 163  
      * <p>Introspects the <code>Throwable</code> to obtain the root cause.</p>
 164  
      *
 165  
      * <p>This method walks through the exception chain to the last element,
 166  
      * "root" of the tree, using {@link #getCause(Throwable)}, and
 167  
      * returns that exception.</p>
 168  
      *
 169  
      * <p>From version 2.2, this method handles recursive cause structures
 170  
      * that might otherwise cause infinite loops. If the throwable parameter
 171  
      * has a cause of itself, then null will be returned. If the throwable
 172  
      * parameter cause chain loops, the last element in the chain before the
 173  
      * loop is returned.</p>
 174  
      *
 175  
      * @param throwable  the throwable to get the root cause for, may be null
 176  
      * @return the root cause of the <code>Throwable</code>,
 177  
      *  <code>null</code> if none found or null throwable input
 178  
      */
 179  
     public static Throwable getRootCause(final Throwable throwable) {
 180  9
         final List<Throwable> list = getThrowableList(throwable);
 181  9
         return list.size() < 2 ? null : (Throwable)list.get(list.size() - 1);
 182  
     }
 183  
 
 184  
     /**
 185  
      * <p>Finds a <code>Throwable</code> by method name.</p>
 186  
      *
 187  
      * @param throwable  the exception to examine
 188  
      * @param methodName  the name of the method to find and invoke
 189  
      * @return the wrapped exception, or <code>null</code> if not found
 190  
      */
 191  
     // TODO: Remove in Lang 4.0
 192  
     private static Throwable getCauseUsingMethodName(final Throwable throwable, final String methodName) {
 193  1000
         Method method = null;
 194  
         try {
 195  1000
             method = throwable.getClass().getMethod(methodName);
 196  757
         } catch (final NoSuchMethodException ignored) { // NOPMD
 197  
             // exception ignored
 198  0
         } catch (final SecurityException ignored) { // NOPMD
 199  
             // exception ignored
 200  1000
         }
 201  
 
 202  1000
         if (method != null && Throwable.class.isAssignableFrom(method.getReturnType())) {
 203  
             try {
 204  174
                 return (Throwable) method.invoke(throwable);
 205  0
             } catch (final IllegalAccessException ignored) { // NOPMD
 206  
                 // exception ignored
 207  0
             } catch (final IllegalArgumentException ignored) { // NOPMD
 208  
                 // exception ignored
 209  0
             } catch (final InvocationTargetException ignored) { // NOPMD
 210  
                 // exception ignored
 211  0
             }
 212  
         }
 213  826
         return null;
 214  
     }
 215  
 
 216  
     //-----------------------------------------------------------------------
 217  
     /**
 218  
      * <p>Counts the number of <code>Throwable</code> objects in the
 219  
      * exception chain.</p>
 220  
      *
 221  
      * <p>A throwable without cause will return <code>1</code>.
 222  
      * A throwable with one cause will return <code>2</code> and so on.
 223  
      * A <code>null</code> throwable will return <code>0</code>.</p>
 224  
      *
 225  
      * <p>From version 2.2, this method handles recursive cause structures
 226  
      * that might otherwise cause infinite loops. The cause chain is
 227  
      * processed until the end is reached, or until the next item in the
 228  
      * chain is already in the result set.</p>
 229  
      *
 230  
      * @param throwable  the throwable to inspect, may be null
 231  
      * @return the count of throwables, zero if null input
 232  
      */
 233  
     public static int getThrowableCount(final Throwable throwable) {
 234  6
         return getThrowableList(throwable).size();
 235  
     }
 236  
 
 237  
     /**
 238  
      * <p>Returns the list of <code>Throwable</code> objects in the
 239  
      * exception chain.</p>
 240  
      *
 241  
      * <p>A throwable without cause will return an array containing
 242  
      * one element - the input throwable.
 243  
      * A throwable with one cause will return an array containing
 244  
      * two elements. - the input throwable and the cause throwable.
 245  
      * A <code>null</code> throwable will return an array of size zero.</p>
 246  
      *
 247  
      * <p>From version 2.2, this method handles recursive cause structures
 248  
      * that might otherwise cause infinite loops. The cause chain is
 249  
      * processed until the end is reached, or until the next item in the
 250  
      * chain is already in the result set.</p>
 251  
      *
 252  
      * @see #getThrowableList(Throwable)
 253  
      * @param throwable  the throwable to inspect, may be null
 254  
      * @return the array of throwables, never null
 255  
      */
 256  
     public static Throwable[] getThrowables(final Throwable throwable) {
 257  60
         final List<Throwable> list = getThrowableList(throwable);
 258  60
         return list.toArray(new Throwable[list.size()]);
 259  
     }
 260  
 
 261  
     /**
 262  
      * <p>Returns the list of <code>Throwable</code> objects in the
 263  
      * exception chain.</p>
 264  
      *
 265  
      * <p>A throwable without cause will return a list containing
 266  
      * one element - the input throwable.
 267  
      * A throwable with one cause will return a list containing
 268  
      * two elements. - the input throwable and the cause throwable.
 269  
      * A <code>null</code> throwable will return a list of size zero.</p>
 270  
      *
 271  
      * <p>This method handles recursive cause structures that might
 272  
      * otherwise cause infinite loops. The cause chain is processed until
 273  
      * the end is reached, or until the next item in the chain is already
 274  
      * in the result set.</p>
 275  
      *
 276  
      * @param throwable  the throwable to inspect, may be null
 277  
      * @return the list of throwables, never null
 278  
      * @since Commons Lang 2.2
 279  
      */
 280  
     public static List<Throwable> getThrowableList(Throwable throwable) {
 281  81
         final List<Throwable> list = new ArrayList<Throwable>();
 282  244
         while (throwable != null && list.contains(throwable) == false) {
 283  163
             list.add(throwable);
 284  163
             throwable = ExceptionUtils.getCause(throwable);
 285  
         }
 286  81
         return list;
 287  
     }
 288  
 
 289  
     //-----------------------------------------------------------------------
 290  
     /**
 291  
      * <p>Returns the (zero based) index of the first <code>Throwable</code>
 292  
      * that matches the specified class (exactly) in the exception chain.
 293  
      * Subclasses of the specified class do not match - see
 294  
      * {@link #indexOfType(Throwable, Class)} for the opposite.</p>
 295  
      *
 296  
      * <p>A <code>null</code> throwable returns <code>-1</code>.
 297  
      * A <code>null</code> type returns <code>-1</code>.
 298  
      * No match in the chain returns <code>-1</code>.</p>
 299  
      *
 300  
      * @param throwable  the throwable to inspect, may be null
 301  
      * @param clazz  the class to search for, subclasses do not match, null returns -1
 302  
      * @return the index into the throwable chain, -1 if no match or null input
 303  
      */
 304  
     public static int indexOfThrowable(final Throwable throwable, final Class<?> clazz) {
 305  17
         return indexOf(throwable, clazz, 0, false);
 306  
     }
 307  
 
 308  
     /**
 309  
      * <p>Returns the (zero based) index of the first <code>Throwable</code>
 310  
      * that matches the specified type in the exception chain from
 311  
      * a specified index.
 312  
      * Subclasses of the specified class do not match - see
 313  
      * {@link #indexOfType(Throwable, Class, int)} for the opposite.</p>
 314  
      *
 315  
      * <p>A <code>null</code> throwable returns <code>-1</code>.
 316  
      * A <code>null</code> type returns <code>-1</code>.
 317  
      * No match in the chain returns <code>-1</code>.
 318  
      * A negative start index is treated as zero.
 319  
      * A start index greater than the number of throwables returns <code>-1</code>.</p>
 320  
      *
 321  
      * @param throwable  the throwable to inspect, may be null
 322  
      * @param clazz  the class to search for, subclasses do not match, null returns -1
 323  
      * @param fromIndex  the (zero based) index of the starting position,
 324  
      *  negative treated as zero, larger than chain size returns -1
 325  
      * @return the index into the throwable chain, -1 if no match or null input
 326  
      */
 327  
     public static int indexOfThrowable(final Throwable throwable, final Class<?> clazz, final int fromIndex) {
 328  17
         return indexOf(throwable, clazz, fromIndex, false);
 329  
     }
 330  
 
 331  
     //-----------------------------------------------------------------------
 332  
     /**
 333  
      * <p>Returns the (zero based) index of the first <code>Throwable</code>
 334  
      * that matches the specified class or subclass in the exception chain.
 335  
      * Subclasses of the specified class do match - see
 336  
      * {@link #indexOfThrowable(Throwable, Class)} for the opposite.</p>
 337  
      *
 338  
      * <p>A <code>null</code> throwable returns <code>-1</code>.
 339  
      * A <code>null</code> type returns <code>-1</code>.
 340  
      * No match in the chain returns <code>-1</code>.</p>
 341  
      *
 342  
      * @param throwable  the throwable to inspect, may be null
 343  
      * @param type  the type to search for, subclasses match, null returns -1
 344  
      * @return the index into the throwable chain, -1 if no match or null input
 345  
      * @since 2.1
 346  
      */
 347  
     public static int indexOfType(final Throwable throwable, final Class<?> type) {
 348  17
         return indexOf(throwable, type, 0, true);
 349  
     }
 350  
 
 351  
     /**
 352  
      * <p>Returns the (zero based) index of the first <code>Throwable</code>
 353  
      * that matches the specified type in the exception chain from
 354  
      * a specified index.
 355  
      * Subclasses of the specified class do match - see
 356  
      * {@link #indexOfThrowable(Throwable, Class)} for the opposite.</p>
 357  
      *
 358  
      * <p>A <code>null</code> throwable returns <code>-1</code>.
 359  
      * A <code>null</code> type returns <code>-1</code>.
 360  
      * No match in the chain returns <code>-1</code>.
 361  
      * A negative start index is treated as zero.
 362  
      * A start index greater than the number of throwables returns <code>-1</code>.</p>
 363  
      *
 364  
      * @param throwable  the throwable to inspect, may be null
 365  
      * @param type  the type to search for, subclasses match, null returns -1
 366  
      * @param fromIndex  the (zero based) index of the starting position,
 367  
      *  negative treated as zero, larger than chain size returns -1
 368  
      * @return the index into the throwable chain, -1 if no match or null input
 369  
      * @since 2.1
 370  
      */
 371  
     public static int indexOfType(final Throwable throwable, final Class<?> type, final int fromIndex) {
 372  17
         return indexOf(throwable, type, fromIndex, true);
 373  
     }
 374  
 
 375  
     /**
 376  
      * <p>Worker method for the <code>indexOfType</code> methods.</p>
 377  
      *
 378  
      * @param throwable  the throwable to inspect, may be null
 379  
      * @param type  the type to search for, subclasses match, null returns -1
 380  
      * @param fromIndex  the (zero based) index of the starting position,
 381  
      *  negative treated as zero, larger than chain size returns -1
 382  
      * @param subclass if <code>true</code>, compares with {@link Class#isAssignableFrom(Class)}, otherwise compares
 383  
      * using references
 384  
      * @return index of the <code>type</code> within throwables nested within the specified <code>throwable</code>
 385  
      */
 386  
     private static int indexOf(final Throwable throwable, final Class<?> type, int fromIndex, final boolean subclass) {
 387  68
         if (throwable == null || type == null) {
 388  20
             return -1;
 389  
         }
 390  48
         if (fromIndex < 0) {
 391  2
             fromIndex = 0;
 392  
         }
 393  48
         final Throwable[] throwables = ExceptionUtils.getThrowables(throwable);
 394  48
         if (fromIndex >= throwables.length) {
 395  2
             return -1;
 396  
         }
 397  46
         if (subclass) {
 398  41
             for (int i = fromIndex; i < throwables.length; i++) {
 399  34
                 if (type.isAssignableFrom(throwables[i].getClass())) {
 400  16
                     return i;
 401  
                 }
 402  
             }
 403  
         } else {
 404  47
             for (int i = fromIndex; i < throwables.length; i++) {
 405  38
                 if (type.equals(throwables[i].getClass())) {
 406  14
                     return i;
 407  
                 }
 408  
             }
 409  
         }
 410  16
         return -1;
 411  
     }
 412  
 
 413  
     //-----------------------------------------------------------------------
 414  
     /**
 415  
      * <p>Prints a compact stack trace for the root cause of a throwable
 416  
      * to <code>System.err</code>.</p>
 417  
      *
 418  
      * <p>The compact stack trace starts with the root cause and prints
 419  
      * stack frames up to the place where it was caught and wrapped.
 420  
      * Then it prints the wrapped exception and continues with stack frames
 421  
      * until the wrapper exception is caught and wrapped again, etc.</p>
 422  
      *
 423  
      * <p>The output of this method is consistent across JDK versions.
 424  
      * Note that this is the opposite order to the JDK1.4 display.</p>
 425  
      *
 426  
      * <p>The method is equivalent to <code>printStackTrace</code> for throwables
 427  
      * that don't have nested causes.</p>
 428  
      *
 429  
      * @param throwable  the throwable to output
 430  
      * @since 2.0
 431  
      */
 432  
     public static void printRootCauseStackTrace(final Throwable throwable) {
 433  1
         printRootCauseStackTrace(throwable, System.err);
 434  1
     }
 435  
 
 436  
     /**
 437  
      * <p>Prints a compact stack trace for the root cause of a throwable.</p>
 438  
      *
 439  
      * <p>The compact stack trace starts with the root cause and prints
 440  
      * stack frames up to the place where it was caught and wrapped.
 441  
      * Then it prints the wrapped exception and continues with stack frames
 442  
      * until the wrapper exception is caught and wrapped again, etc.</p>
 443  
      *
 444  
      * <p>The output of this method is consistent across JDK versions.
 445  
      * Note that this is the opposite order to the JDK1.4 display.</p>
 446  
      *
 447  
      * <p>The method is equivalent to <code>printStackTrace</code> for throwables
 448  
      * that don't have nested causes.</p>
 449  
      *
 450  
      * @param throwable  the throwable to output, may be null
 451  
      * @param stream  the stream to output to, may not be null
 452  
      * @throws IllegalArgumentException if the stream is <code>null</code>
 453  
      * @since 2.0
 454  
      */
 455  
     public static void printRootCauseStackTrace(final Throwable throwable, final PrintStream stream) {
 456  6
         if (throwable == null) {
 457  3
             return;
 458  
         }
 459  3
         if (stream == null) {
 460  1
             throw new IllegalArgumentException("The PrintStream must not be null");
 461  
         }
 462  2
         final String trace[] = getRootCauseStackTrace(throwable);
 463  61
         for (final String element : trace) {
 464  59
             stream.println(element);
 465  
         }
 466  2
         stream.flush();
 467  2
     }
 468  
 
 469  
     /**
 470  
      * <p>Prints a compact stack trace for the root cause of a throwable.</p>
 471  
      *
 472  
      * <p>The compact stack trace starts with the root cause and prints
 473  
      * stack frames up to the place where it was caught and wrapped.
 474  
      * Then it prints the wrapped exception and continues with stack frames
 475  
      * until the wrapper exception is caught and wrapped again, etc.</p>
 476  
      *
 477  
      * <p>The output of this method is consistent across JDK versions.
 478  
      * Note that this is the opposite order to the JDK1.4 display.</p>
 479  
      *
 480  
      * <p>The method is equivalent to <code>printStackTrace</code> for throwables
 481  
      * that don't have nested causes.</p>
 482  
      *
 483  
      * @param throwable  the throwable to output, may be null
 484  
      * @param writer  the writer to output to, may not be null
 485  
      * @throws IllegalArgumentException if the writer is <code>null</code>
 486  
      * @since 2.0
 487  
      */
 488  
     public static void printRootCauseStackTrace(final Throwable throwable, final PrintWriter writer) {
 489  5
         if (throwable == null) {
 490  2
             return;
 491  
         }
 492  3
         if (writer == null) {
 493  1
             throw new IllegalArgumentException("The PrintWriter must not be null");
 494  
         }
 495  2
         final String trace[] = getRootCauseStackTrace(throwable);
 496  61
         for (final String element : trace) {
 497  59
             writer.println(element);
 498  
         }
 499  2
         writer.flush();
 500  2
     }
 501  
 
 502  
     //-----------------------------------------------------------------------
 503  
     /**
 504  
      * <p>Creates a compact stack trace for the root cause of the supplied
 505  
      * <code>Throwable</code>.</p>
 506  
      *
 507  
      * <p>The output of this method is consistent across JDK versions.
 508  
      * It consists of the root exception followed by each of its wrapping
 509  
      * exceptions separated by '[wrapped]'. Note that this is the opposite
 510  
      * order to the JDK1.4 display.</p>
 511  
      *
 512  
      * @param throwable  the throwable to examine, may be null
 513  
      * @return an array of stack trace frames, never null
 514  
      * @since 2.0
 515  
      */
 516  
     public static String[] getRootCauseStackTrace(final Throwable throwable) {
 517  7
         if (throwable == null) {
 518  1
             return ArrayUtils.EMPTY_STRING_ARRAY;
 519  
         }
 520  6
         final Throwable throwables[] = getThrowables(throwable);
 521  6
         final int count = throwables.length;
 522  6
         final List<String> frames = new ArrayList<String>();
 523  6
         List<String> nextTrace = getStackFrameList(throwables[count - 1]);
 524  6
         for (int i = count; --i >= 0;) {
 525  12
             final List<String> trace = nextTrace;
 526  12
             if (i != 0) {
 527  6
                 nextTrace = getStackFrameList(throwables[i - 1]);
 528  6
                 removeCommonFrames(trace, nextTrace);
 529  
             }
 530  12
             if (i == count - 1) {
 531  6
                 frames.add(throwables[i].toString());
 532  
             } else {
 533  6
                 frames.add(WRAPPED_MARKER + throwables[i].toString());
 534  
             }
 535  176
             for (int j = 0; j < trace.size(); j++) {
 536  164
                 frames.add(trace.get(j));
 537  
             }
 538  12
         }
 539  6
         return frames.toArray(new String[frames.size()]);
 540  
     }
 541  
 
 542  
     /**
 543  
      * <p>Removes common frames from the cause trace given the two stack traces.</p>
 544  
      *
 545  
      * @param causeFrames  stack trace of a cause throwable
 546  
      * @param wrapperFrames  stack trace of a wrapper throwable
 547  
      * @throws IllegalArgumentException if either argument is null
 548  
      * @since 2.0
 549  
      */
 550  
     public static void removeCommonFrames(final List<String> causeFrames, final List<String> wrapperFrames) {
 551  7
         if (causeFrames == null || wrapperFrames == null) {
 552  1
             throw new IllegalArgumentException("The List must not be null");
 553  
         }
 554  6
         int causeFrameIndex = causeFrames.size() - 1;
 555  6
         int wrapperFrameIndex = wrapperFrames.size() - 1;
 556  168
         while (causeFrameIndex >= 0 && wrapperFrameIndex >= 0) {
 557  
             // Remove the frame from the cause trace if it is the same
 558  
             // as in the wrapper trace
 559  162
             final String causeFrame = causeFrames.get(causeFrameIndex);
 560  162
             final String wrapperFrame = wrapperFrames.get(wrapperFrameIndex);
 561  162
             if (causeFrame.equals(wrapperFrame)) {
 562  159
                 causeFrames.remove(causeFrameIndex);
 563  
             }
 564  162
             causeFrameIndex--;
 565  162
             wrapperFrameIndex--;
 566  162
         }
 567  6
     }
 568  
 
 569  
     //-----------------------------------------------------------------------
 570  
     /**
 571  
      * <p>Gets the stack trace from a Throwable as a String.</p>
 572  
      *
 573  
      * <p>The result of this method vary by JDK version as this method
 574  
      * uses {@link Throwable#printStackTrace(java.io.PrintWriter)}.
 575  
      * On JDK1.3 and earlier, the cause exception will not be shown
 576  
      * unless the specified throwable alters printStackTrace.</p>
 577  
      *
 578  
      * @param throwable  the <code>Throwable</code> to be examined
 579  
      * @return the stack trace as generated by the exception's
 580  
      *  <code>printStackTrace(PrintWriter)</code> method
 581  
      */
 582  
     public static String getStackTrace(final Throwable throwable) {
 583  33
         final StringWriter sw = new StringWriter();
 584  33
         final PrintWriter pw = new PrintWriter(sw, true);
 585  33
         throwable.printStackTrace(pw);
 586  33
         return sw.getBuffer().toString();
 587  
     }
 588  
 
 589  
     /**
 590  
      * <p>Captures the stack trace associated with the specified
 591  
      * <code>Throwable</code> object, decomposing it into a list of
 592  
      * stack frames.</p>
 593  
      *
 594  
      * <p>The result of this method vary by JDK version as this method
 595  
      * uses {@link Throwable#printStackTrace(java.io.PrintWriter)}.
 596  
      * On JDK1.3 and earlier, the cause exception will not be shown
 597  
      * unless the specified throwable alters printStackTrace.</p>
 598  
      *
 599  
      * @param throwable  the <code>Throwable</code> to examine, may be null
 600  
      * @return an array of strings describing each stack frame, never null
 601  
      */
 602  
     public static String[] getStackFrames(final Throwable throwable) {
 603  0
         if (throwable == null) {
 604  0
             return ArrayUtils.EMPTY_STRING_ARRAY;
 605  
         }
 606  0
         return getStackFrames(getStackTrace(throwable));
 607  
     }
 608  
 
 609  
     //-----------------------------------------------------------------------
 610  
     /**
 611  
      * <p>Returns an array where each element is a line from the argument.</p>
 612  
      *
 613  
      * <p>The end of line is determined by the value of {@link SystemUtils#LINE_SEPARATOR}.</p>
 614  
      *
 615  
      * @param stackTrace  a stack trace String
 616  
      * @return an array where each element is a line from the argument
 617  
      */
 618  
     static String[] getStackFrames(final String stackTrace) {
 619  0
         final String linebreak = SystemUtils.LINE_SEPARATOR;
 620  0
         final StringTokenizer frames = new StringTokenizer(stackTrace, linebreak);
 621  0
         final List<String> list = new ArrayList<String>();
 622  0
         while (frames.hasMoreTokens()) {
 623  0
             list.add(frames.nextToken());
 624  
         }
 625  0
         return list.toArray(new String[list.size()]);
 626  
     }
 627  
 
 628  
     /**
 629  
      * <p>Produces a <code>List</code> of stack frames - the message
 630  
      * is not included. Only the trace of the specified exception is
 631  
      * returned, any caused by trace is stripped.</p>
 632  
      *
 633  
      * <p>This works in most cases - it will only fail if the exception
 634  
      * message contains a line that starts with:
 635  
      * <code>&quot;&nbsp;&nbsp;&nbsp;at&quot;.</code></p>
 636  
      * 
 637  
      * @param t is any throwable
 638  
      * @return List of stack frames
 639  
      */
 640  
     static List<String> getStackFrameList(final Throwable t) {
 641  12
         final String stackTrace = getStackTrace(t);
 642  12
         final String linebreak = SystemUtils.LINE_SEPARATOR;
 643  12
         final StringTokenizer frames = new StringTokenizer(stackTrace, linebreak);
 644  12
         final List<String> list = new ArrayList<String>();
 645  12
         boolean traceStarted = false;
 646  347
         while (frames.hasMoreTokens()) {
 647  341
             final String token = frames.nextToken();
 648  
             // Determine if the line starts with <whitespace>at
 649  341
             final int at = token.indexOf("at");
 650  341
             if (at != -1 && token.substring(0, at).trim().isEmpty()) {
 651  323
                 traceStarted = true;
 652  323
                 list.add(token);
 653  18
             } else if (traceStarted) {
 654  6
                 break;
 655  
             }
 656  335
         }
 657  12
         return list;
 658  
     }
 659  
 
 660  
     //-----------------------------------------------------------------------
 661  
     /**
 662  
      * Gets a short message summarising the exception.
 663  
      * <p>
 664  
      * The message returned is of the form
 665  
      * {ClassNameWithoutPackage}: {ThrowableMessage}
 666  
      *
 667  
      * @param th  the throwable to get a message for, null returns empty string
 668  
      * @return the message, non-null
 669  
      * @since Commons Lang 2.2
 670  
      */
 671  
     public static String getMessage(final Throwable th) {
 672  6
         if (th == null) {
 673  2
             return "";
 674  
         }
 675  4
         final String clsName = ClassUtils.getShortClassName(th, null);
 676  4
         final String msg = th.getMessage();
 677  4
         return clsName + ": " + StringUtils.defaultString(msg);
 678  
     }
 679  
 
 680  
     //-----------------------------------------------------------------------
 681  
     /**
 682  
      * Gets a short message summarising the root cause exception.
 683  
      * <p>
 684  
      * The message returned is of the form
 685  
      * {ClassNameWithoutPackage}: {ThrowableMessage}
 686  
      *
 687  
      * @param th  the throwable to get a message for, null returns empty string
 688  
      * @return the message, non-null
 689  
      * @since Commons Lang 2.2
 690  
      */
 691  
     public static String getRootCauseMessage(final Throwable th) {
 692  3
         Throwable root = ExceptionUtils.getRootCause(th);
 693  3
         root = root == null ? th : root;
 694  3
         return getMessage(root);
 695  
     }
 696  
 
 697  
 }