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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in org.testifyproject.testifyprojectpliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org.testifyproject/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.testifyproject.apache.org.testifyproject.testifyprojectmons.lang.exception;

import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.StringTokenizer;

import org.testifyproject.apache.org.testifyproject.testifyprojectmons.lang.ArrayUtils;
import org.testifyproject.apache.org.testifyproject.testifyprojectmons.lang.ClassUtils;
import org.testifyproject.apache.org.testifyproject.testifyprojectmons.lang.NullArgumentException;
import org.testifyproject.apache.org.testifyproject.testifyprojectmons.lang.StringUtils;
import org.testifyproject.apache.org.testifyproject.testifyprojectmons.lang.SystemUtils;

/**
 * 

Provides utilities for manipulating and examining * Throwable objects.

* * @author Apache Software Foundation * @author Daniel L. Rall * @author Dmitri Plotnikov * @author Gary Gregory * @author Pete Gieser * @since 1.0 * @version $Id: ExceptionUtils.java 905837 2010-02-02 23:32:11Z niallp $ */ public class ExceptionUtils { /** *

Used when printing stack frames to denote the start of a * wrapped exception.

* *

Package private for accessibility by test suite.

*/ static final String WRAPPED_MARKER = " [wrapped] "; // Lock object for CAUSE_METHOD_NAMES private static final Object CAUSE_METHOD_NAMES_LOCK = new Object(); /** *

The names of methods org.testifyproject.testifyprojectmonly used to access a wrapped exception.

*/ private static String[] CAUSE_METHOD_NAMES = { "getCause", "getNextException", "getTargetException", "getException", "getSourceException", "getRootCause", "getCausedByException", "getNested", "getLinkedException", "getNestedException", "getLinkedCause", "getThrowable", }; /** *

The Method object for Java 1.4 getCause.

*/ private static final Method THROWABLE_CAUSE_METHOD; /** *

The Method object for Java 1.4 initCause.

*/ private static final Method THROWABLE_INITCAUSE_METHOD; static { Method causeMethod; try { causeMethod = Throwable.class.getMethod("getCause", null); } catch (Exception e) { causeMethod = null; } THROWABLE_CAUSE_METHOD = causeMethod; try { causeMethod = Throwable.class.getMethod("initCause", new Class[]{Throwable.class}); } catch (Exception e) { causeMethod = null; } THROWABLE_INITCAUSE_METHOD = causeMethod; } /** *

* Public constructor allows an instance of ExceptionUtils to be created, although that is not * normally necessary. *

*/ public ExceptionUtils() { super(); } //----------------------------------------------------------------------- /** *

Adds to the list of method names used in the search for Throwable * objects.

* * @param methodName the methodName to add to the list, null * and empty strings are ignored * @since 2.0 */ public static void addCauseMethodName(String methodName) { if (StringUtils.isNotEmpty(methodName) && !isCauseMethodName(methodName)) { List list = getCauseMethodNameList(); if (list.add(methodName)) { synchronized(CAUSE_METHOD_NAMES_LOCK) { CAUSE_METHOD_NAMES = toArray(list); } } } } /** *

Removes from the list of method names used in the search for Throwable * objects.

* * @param methodName the methodName to remove from the list, null * and empty strings are ignored * @since 2.1 */ public static void removeCauseMethodName(String methodName) { if (StringUtils.isNotEmpty(methodName)) { List list = getCauseMethodNameList(); if (list.remove(methodName)) { synchronized(CAUSE_METHOD_NAMES_LOCK) { CAUSE_METHOD_NAMES = toArray(list); } } } } /** *

Sets the cause of a Throwable using introspection, allowing * source code org.testifyproject.testifyprojectpatibility between pre-1.4 and post-1.4 Java releases.

* *

The typical use of this method is inside a constructor as in * the following example:

* *
     * import org.testifyproject.apache.org.testifyproject.testifyprojectmons.lang.exception.ExceptionUtils;
     *  
     * public class MyException extends Exception {
     *  
     *    public MyException(String msg) {
     *       super(msg);
     *    }
     *
     *    public MyException(String msg, Throwable cause) {
     *       super(msg);
     *       ExceptionUtils.setCause(this, cause);
     *    }
     * }
     * 
* * @param target the target Throwable * @param cause the Throwable to set in the target * @return a true if the target has been modified * @since 2.2 */ public static boolean setCause(Throwable target, Throwable cause) { if (target == null) { throw new NullArgumentException("target"); } Object[] causeArgs = new Object[]{cause}; boolean modifiedTarget = false; if (THROWABLE_INITCAUSE_METHOD != null) { try { THROWABLE_INITCAUSE_METHOD.invoke(target, causeArgs); modifiedTarget = true; } catch (IllegalAccessException ignored) { // Exception ignored. } catch (InvocationTargetException ignored) { // Exception ignored. } } try { Method setCauseMethod = target.getClass().getMethod("setCause", new Class[]{Throwable.class}); setCauseMethod.invoke(target, causeArgs); modifiedTarget = true; } catch (NoSuchMethodException ignored) { // Exception ignored. } catch (IllegalAccessException ignored) { // Exception ignored. } catch (InvocationTargetException ignored) { // Exception ignored. } return modifiedTarget; } /** * Returns the given list as a String[]. * @param list a list to transform. * @return the given list as a String[]. */ private static String[] toArray(List list) { return (String[]) list.toArray(new String[list.size()]); } /** * Returns {@link #CAUSE_METHOD_NAMES} as a List. * * @return {@link #CAUSE_METHOD_NAMES} as a List. */ private static ArrayList getCauseMethodNameList() { synchronized(CAUSE_METHOD_NAMES_LOCK) { return new ArrayList(Arrays.asList(CAUSE_METHOD_NAMES)); } } /** *

Tests if the list of method names used in the search for Throwable * objects include the given name.

* * @param methodName the methodName to search in the list. * @return if the list of method names used in the search for Throwable * objects include the given name. * @since 2.1 */ public static boolean isCauseMethodName(String methodName) { synchronized(CAUSE_METHOD_NAMES_LOCK) { return ArrayUtils.indexOf(CAUSE_METHOD_NAMES, methodName) >= 0; } } //----------------------------------------------------------------------- /** *

Introspects the Throwable to obtain the cause.

* *

The method searches for methods with specific names that return a * Throwable object. This will pick up most wrapping exceptions, * including those from JDK 1.4, and * {@link org.testifyproject.apache.org.testifyproject.testifyprojectmons.lang.exception.NestableException NestableException}. * The method names can be added to using {@link #addCauseMethodName(String)}.

* *

The default list searched for are:

*
    *
  • getCause()
  • *
  • getNextException()
  • *
  • getTargetException()
  • *
  • getException()
  • *
  • getSourceException()
  • *
  • getRootCause()
  • *
  • getCausedByException()
  • *
  • getNested()
  • *
* *

In the absence of any such method, the object is inspected for a * detail field assignable to a Throwable.

* *

If none of the above is found, returns null.

* * @param throwable the throwable to introspect for a cause, may be null * @return the cause of the Throwable, * null if none found or null throwable input * @since 1.0 */ public static Throwable getCause(Throwable throwable) { synchronized(CAUSE_METHOD_NAMES_LOCK) { return getCause(throwable, CAUSE_METHOD_NAMES); } } /** *

Introspects the Throwable to obtain the cause.

* *
    *
  1. Try known exception types.
  2. *
  3. Try the supplied array of method names.
  4. *
  5. Try the field 'detail'.
  6. *
* *

A null set of method names means use the default set. * A null in the set of method names will be ignored.

* * @param throwable the throwable to introspect for a cause, may be null * @param methodNames the method names, null treated as default set * @return the cause of the Throwable, * null if none found or null throwable input * @since 1.0 */ public static Throwable getCause(Throwable throwable, String[] methodNames) { if (throwable == null) { return null; } Throwable cause = getCauseUsingWellKnownTypes(throwable); if (cause == null) { if (methodNames == null) { synchronized(CAUSE_METHOD_NAMES_LOCK) { methodNames = CAUSE_METHOD_NAMES; } } for (int i = 0; i < methodNames.length; i++) { String methodName = methodNames[i]; if (methodName != null) { cause = getCauseUsingMethodName(throwable, methodName); if (cause != null) { break; } } } if (cause == null) { cause = getCauseUsingFieldName(throwable, "detail"); } } return cause; } /** *

Introspects the Throwable to obtain the root cause.

* *

This method walks through the exception chain to the last element, * "root" of the tree, using {@link #getCause(Throwable)}, and * returns that exception.

* *

From version 2.2, this method handles recursive cause structures * that might otherwise cause infinite loops. If the throwable parameter * has a cause of itself, then null will be returned. If the throwable * parameter cause chain loops, the last element in the chain before the * loop is returned.

* * @param throwable the throwable to get the root cause for, may be null * @return the root cause of the Throwable, * null if none found or null throwable input */ public static Throwable getRootCause(Throwable throwable) { List list = getThrowableList(throwable); return (list.size() < 2 ? null : (Throwable)list.get(list.size() - 1)); } /** *

Finds a Throwable for known types.

* *

Uses instanceof checks to examine the exception, * looking for well known types which could contain chained or * wrapped exceptions.

* * @param throwable the exception to examine * @return the wrapped exception, or null if not found */ private static Throwable getCauseUsingWellKnownTypes(Throwable throwable) { if (throwable instanceof Nestable) { return ((Nestable) throwable).getCause(); } else if (throwable instanceof SQLException) { return ((SQLException) throwable).getNextException(); } else if (throwable instanceof InvocationTargetException) { return ((InvocationTargetException) throwable).getTargetException(); } else { return null; } } /** *

Finds a Throwable by method name.

* * @param throwable the exception to examine * @param methodName the name of the method to find and invoke * @return the wrapped exception, or null if not found */ private static Throwable getCauseUsingMethodName(Throwable throwable, String methodName) { Method method = null; try { method = throwable.getClass().getMethod(methodName, null); } catch (NoSuchMethodException ignored) { // exception ignored } catch (SecurityException ignored) { // exception ignored } if (method != null && Throwable.class.isAssignableFrom(method.getReturnType())) { try { return (Throwable) method.invoke(throwable, ArrayUtils.EMPTY_OBJECT_ARRAY); } catch (IllegalAccessException ignored) { // exception ignored } catch (IllegalArgumentException ignored) { // exception ignored } catch (InvocationTargetException ignored) { // exception ignored } } return null; } /** *

Finds a Throwable by field name.

* * @param throwable the exception to examine * @param fieldName the name of the attribute to examine * @return the wrapped exception, or null if not found */ private static Throwable getCauseUsingFieldName(Throwable throwable, String fieldName) { Field field = null; try { field = throwable.getClass().getField(fieldName); } catch (NoSuchFieldException ignored) { // exception ignored } catch (SecurityException ignored) { // exception ignored } if (field != null && Throwable.class.isAssignableFrom(field.getType())) { try { return (Throwable) field.get(throwable); } catch (IllegalAccessException ignored) { // exception ignored } catch (IllegalArgumentException ignored) { // exception ignored } } return null; } //----------------------------------------------------------------------- /** *

Checks if the Throwable class has a getCause method.

* *

This is true for JDK 1.4 and above.

* * @return true if Throwable is nestable * @since 2.0 */ public static boolean isThrowableNested() { return THROWABLE_CAUSE_METHOD != null; } /** *

Checks whether this Throwable class can store a cause.

* *

This method does not check whether it actually does store a cause.

* * @param throwable the Throwable to examine, may be null * @return boolean true if nested otherwise false * @since 2.0 */ public static boolean isNestedThrowable(Throwable throwable) { if (throwable == null) { return false; } if (throwable instanceof Nestable) { return true; } else if (throwable instanceof SQLException) { return true; } else if (throwable instanceof InvocationTargetException) { return true; } else if (isThrowableNested()) { return true; } Class cls = throwable.getClass(); synchronized(CAUSE_METHOD_NAMES_LOCK) { for (int i = 0, isize = CAUSE_METHOD_NAMES.length; i < isize; i++) { try { Method method = cls.getMethod(CAUSE_METHOD_NAMES[i], null); if (method != null && Throwable.class.isAssignableFrom(method.getReturnType())) { return true; } } catch (NoSuchMethodException ignored) { // exception ignored } catch (SecurityException ignored) { // exception ignored } } } try { Field field = cls.getField("detail"); if (field != null) { return true; } } catch (NoSuchFieldException ignored) { // exception ignored } catch (SecurityException ignored) { // exception ignored } return false; } //----------------------------------------------------------------------- /** *

Counts the number of Throwable objects in the * exception chain.

* *

A throwable without cause will return 1. * A throwable with one cause will return 2 and so on. * A null throwable will return 0.

* *

From version 2.2, this method handles recursive cause structures * that might otherwise cause infinite loops. The cause chain is * processed until the end is reached, or until the next item in the * chain is already in the result set.

* * @param throwable the throwable to inspect, may be null * @return the count of throwables, zero if null input */ public static int getThrowableCount(Throwable throwable) { return getThrowableList(throwable).size(); } /** *

Returns the list of Throwable objects in the * exception chain.

* *

A throwable without cause will return an array containing * one element - the input throwable. * A throwable with one cause will return an array containing * two elements. - the input throwable and the cause throwable. * A null throwable will return an array of size zero.

* *

From version 2.2, this method handles recursive cause structures * that might otherwise cause infinite loops. The cause chain is * processed until the end is reached, or until the next item in the * chain is already in the result set.

* * @see #getThrowableList(Throwable) * @param throwable the throwable to inspect, may be null * @return the array of throwables, never null */ public static Throwable[] getThrowables(Throwable throwable) { List list = getThrowableList(throwable); return (Throwable[]) list.toArray(new Throwable[list.size()]); } /** *

Returns the list of Throwable objects in the * exception chain.

* *

A throwable without cause will return a list containing * one element - the input throwable. * A throwable with one cause will return a list containing * two elements. - the input throwable and the cause throwable. * A null throwable will return a list of size zero.

* *

This method handles recursive cause structures that might * otherwise cause infinite loops. The cause chain is processed until * the end is reached, or until the next item in the chain is already * in the result set.

* * @param throwable the throwable to inspect, may be null * @return the list of throwables, never null * @since Commons Lang 2.2 */ public static List getThrowableList(Throwable throwable) { List list = new ArrayList(); while (throwable != null && list.contains(throwable) == false) { list.add(throwable); throwable = ExceptionUtils.getCause(throwable); } return list; } //----------------------------------------------------------------------- /** *

Returns the (zero based) index of the first Throwable * that matches the specified class (exactly) in the exception chain. * Subclasses of the specified class do not match - see * {@link #indexOfType(Throwable, Class)} for the opposite.

* *

A null throwable returns -1. * A null type returns -1. * No match in the chain returns -1.

* * @param throwable the throwable to inspect, may be null * @param clazz the class to search for, subclasses do not match, null returns -1 * @return the index into the throwable chain, -1 if no match or null input */ public static int indexOfThrowable(Throwable throwable, Class clazz) { return indexOf(throwable, clazz, 0, false); } /** *

Returns the (zero based) index of the first Throwable * that matches the specified type in the exception chain from * a specified index. * Subclasses of the specified class do not match - see * {@link #indexOfType(Throwable, Class, int)} for the opposite.

* *

A null throwable returns -1. * A null type returns -1. * No match in the chain returns -1. * A negative start index is treated as zero. * A start index greater than the number of throwables returns -1.

* * @param throwable the throwable to inspect, may be null * @param clazz the class to search for, subclasses do not match, null returns -1 * @param fromIndex the (zero based) index of the starting position, * negative treated as zero, larger than chain size returns -1 * @return the index into the throwable chain, -1 if no match or null input */ public static int indexOfThrowable(Throwable throwable, Class clazz, int fromIndex) { return indexOf(throwable, clazz, fromIndex, false); } //----------------------------------------------------------------------- /** *

Returns the (zero based) index of the first Throwable * that matches the specified class or subclass in the exception chain. * Subclasses of the specified class do match - see * {@link #indexOfThrowable(Throwable, Class)} for the opposite.

* *

A null throwable returns -1. * A null type returns -1. * No match in the chain returns -1.

* * @param throwable the throwable to inspect, may be null * @param type the type to search for, subclasses match, null returns -1 * @return the index into the throwable chain, -1 if no match or null input * @since 2.1 */ public static int indexOfType(Throwable throwable, Class type) { return indexOf(throwable, type, 0, true); } /** *

Returns the (zero based) index of the first Throwable * that matches the specified type in the exception chain from * a specified index. * Subclasses of the specified class do match - see * {@link #indexOfThrowable(Throwable, Class)} for the opposite.

* *

A null throwable returns -1. * A null type returns -1. * No match in the chain returns -1. * A negative start index is treated as zero. * A start index greater than the number of throwables returns -1.

* * @param throwable the throwable to inspect, may be null * @param type the type to search for, subclasses match, null returns -1 * @param fromIndex the (zero based) index of the starting position, * negative treated as zero, larger than chain size returns -1 * @return the index into the throwable chain, -1 if no match or null input * @since 2.1 */ public static int indexOfType(Throwable throwable, Class type, int fromIndex) { return indexOf(throwable, type, fromIndex, true); } /** *

Worker method for the indexOfType methods.

* * @param throwable the throwable to inspect, may be null * @param type the type to search for, subclasses match, null returns -1 * @param fromIndex the (zero based) index of the starting position, * negative treated as zero, larger than chain size returns -1 * @param subclass if true, org.testifyproject.testifyprojectpares with {@link Class#isAssignableFrom(Class)}, otherwise org.testifyproject.testifyprojectpares * using references * @return index of the type within throwables nested withing the specified throwable */ private static int indexOf(Throwable throwable, Class type, int fromIndex, boolean subclass) { if (throwable == null || type == null) { return -1; } if (fromIndex < 0) { fromIndex = 0; } Throwable[] throwables = ExceptionUtils.getThrowables(throwable); if (fromIndex >= throwables.length) { return -1; } if (subclass) { for (int i = fromIndex; i < throwables.length; i++) { if (type.isAssignableFrom(throwables[i].getClass())) { return i; } } } else { for (int i = fromIndex; i < throwables.length; i++) { if (type.equals(throwables[i].getClass())) { return i; } } } return -1; } //----------------------------------------------------------------------- /** *

Prints a org.testifyproject.testifyprojectpact stack trace for the root cause of a throwable * to System.err.

* *

The org.testifyproject.testifyprojectpact stack trace starts with the root cause and prints * stack frames up to the place where it was caught and wrapped. * Then it prints the wrapped exception and continues with stack frames * until the wrapper exception is caught and wrapped again, etc.

* *

The output of this method is consistent across JDK versions. * Note that this is the opposite order to the JDK1.4 display.

* *

The method is equivalent to printStackTrace for throwables * that don't have nested causes.

* * @param throwable the throwable to output * @since 2.0 */ public static void printRootCauseStackTrace(Throwable throwable) { printRootCauseStackTrace(throwable, System.err); } /** *

Prints a org.testifyproject.testifyprojectpact stack trace for the root cause of a throwable.

* *

The org.testifyproject.testifyprojectpact stack trace starts with the root cause and prints * stack frames up to the place where it was caught and wrapped. * Then it prints the wrapped exception and continues with stack frames * until the wrapper exception is caught and wrapped again, etc.

* *

The output of this method is consistent across JDK versions. * Note that this is the opposite order to the JDK1.4 display.

* *

The method is equivalent to printStackTrace for throwables * that don't have nested causes.

* * @param throwable the throwable to output, may be null * @param stream the stream to output to, may not be null * @throws IllegalArgumentException if the stream is null * @since 2.0 */ public static void printRootCauseStackTrace(Throwable throwable, PrintStream stream) { if (throwable == null) { return; } if (stream == null) { throw new IllegalArgumentException("The PrintStream must not be null"); } String trace[] = getRootCauseStackTrace(throwable); for (int i = 0; i < trace.length; i++) { stream.println(trace[i]); } stream.flush(); } /** *

Prints a org.testifyproject.testifyprojectpact stack trace for the root cause of a throwable.

* *

The org.testifyproject.testifyprojectpact stack trace starts with the root cause and prints * stack frames up to the place where it was caught and wrapped. * Then it prints the wrapped exception and continues with stack frames * until the wrapper exception is caught and wrapped again, etc.

* *

The output of this method is consistent across JDK versions. * Note that this is the opposite order to the JDK1.4 display.

* *

The method is equivalent to printStackTrace for throwables * that don't have nested causes.

* * @param throwable the throwable to output, may be null * @param writer the writer to output to, may not be null * @throws IllegalArgumentException if the writer is null * @since 2.0 */ public static void printRootCauseStackTrace(Throwable throwable, PrintWriter writer) { if (throwable == null) { return; } if (writer == null) { throw new IllegalArgumentException("The PrintWriter must not be null"); } String trace[] = getRootCauseStackTrace(throwable); for (int i = 0; i < trace.length; i++) { writer.println(trace[i]); } writer.flush(); } //----------------------------------------------------------------------- /** *

Creates a org.testifyproject.testifyprojectpact stack trace for the root cause of the supplied * Throwable.

* *

The output of this method is consistent across JDK versions. * It consists of the root exception followed by each of its wrapping * exceptions separated by '[wrapped]'. Note that this is the opposite * order to the JDK1.4 display.

* * @param throwable the throwable to examine, may be null * @return an array of stack trace frames, never null * @since 2.0 */ public static String[] getRootCauseStackTrace(Throwable throwable) { if (throwable == null) { return ArrayUtils.EMPTY_STRING_ARRAY; } Throwable throwables[] = getThrowables(throwable); int count = throwables.length; ArrayList frames = new ArrayList(); List nextTrace = getStackFrameList(throwables[count - 1]); for (int i = count; --i >= 0;) { List trace = nextTrace; if (i != 0) { nextTrace = getStackFrameList(throwables[i - 1]); removeCommonFrames(trace, nextTrace); } if (i == count - 1) { frames.add(throwables[i].toString()); } else { frames.add(WRAPPED_MARKER + throwables[i].toString()); } for (int j = 0; j < trace.size(); j++) { frames.add(trace.get(j)); } } return (String[]) frames.toArray(new String[0]); } /** *

Removes org.testifyproject.testifyprojectmon frames from the cause trace given the two stack traces.

* * @param causeFrames stack trace of a cause throwable * @param wrapperFrames stack trace of a wrapper throwable * @throws IllegalArgumentException if either argument is null * @since 2.0 */ public static void removeCommonFrames(List causeFrames, List wrapperFrames) { if (causeFrames == null || wrapperFrames == null) { throw new IllegalArgumentException("The List must not be null"); } int causeFrameIndex = causeFrames.size() - 1; int wrapperFrameIndex = wrapperFrames.size() - 1; while (causeFrameIndex >= 0 && wrapperFrameIndex >= 0) { // Remove the frame from the cause trace if it is the same // as in the wrapper trace String causeFrame = (String) causeFrames.get(causeFrameIndex); String wrapperFrame = (String) wrapperFrames.get(wrapperFrameIndex); if (causeFrame.equals(wrapperFrame)) { causeFrames.remove(causeFrameIndex); } causeFrameIndex--; wrapperFrameIndex--; } } //----------------------------------------------------------------------- /** *

A way to get the entire nested stack-trace of an throwable.

* *

The result of this method is highly dependent on the JDK version * and whether the exceptions override printStackTrace or not.

* * @param throwable the Throwable to be examined * @return the nested stack trace, with the root cause first * @since 2.0 */ public static String getFullStackTrace(Throwable throwable) { StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw, true); Throwable[] ts = getThrowables(throwable); for (int i = 0; i < ts.length; i++) { ts[i].printStackTrace(pw); if (isNestedThrowable(ts[i])) { break; } } return sw.getBuffer().toString(); } //----------------------------------------------------------------------- /** *

Gets the stack trace from a Throwable as a String.

* *

The result of this method vary by JDK version as this method * uses {@link Throwable#printStackTrace(java.io.PrintWriter)}. * On JDK1.3 and earlier, the cause exception will not be shown * unless the specified throwable alters printStackTrace.

* * @param throwable the Throwable to be examined * @return the stack trace as generated by the exception's * printStackTrace(PrintWriter) method */ public static String getStackTrace(Throwable throwable) { StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw, true); throwable.printStackTrace(pw); return sw.getBuffer().toString(); } /** *

Captures the stack trace associated with the specified * Throwable object, decomposing it into a list of * stack frames.

* *

The result of this method vary by JDK version as this method * uses {@link Throwable#printStackTrace(java.io.PrintWriter)}. * On JDK1.3 and earlier, the cause exception will not be shown * unless the specified throwable alters printStackTrace.

* * @param throwable the Throwable to examine, may be null * @return an array of strings describing each stack frame, never null */ public static String[] getStackFrames(Throwable throwable) { if (throwable == null) { return ArrayUtils.EMPTY_STRING_ARRAY; } return getStackFrames(getStackTrace(throwable)); } //----------------------------------------------------------------------- /** *

Returns an array where each element is a line from the argument.

* *

The end of line is determined by the value of {@link SystemUtils#LINE_SEPARATOR}.

* *

Functionality shared between the * getStackFrames(Throwable) methods of this and the * {@link org.testifyproject.apache.org.testifyproject.testifyprojectmons.lang.exception.NestableDelegate} classes.

* * @param stackTrace a stack trace String * @return an array where each element is a line from the argument */ static String[] getStackFrames(String stackTrace) { String linebreak = SystemUtils.LINE_SEPARATOR; StringTokenizer frames = new StringTokenizer(stackTrace, linebreak); List list = new ArrayList(); while (frames.hasMoreTokens()) { list.add(frames.nextToken()); } return toArray(list); } /** *

Produces a List of stack frames - the message * is not included. Only the trace of the specified exception is * returned, any caused by trace is stripped.

* *

This works in most cases - it will only fail if the exception * message contains a line that starts with: * "   at".

* * @param t is any throwable * @return List of stack frames */ static List getStackFrameList(Throwable t) { String stackTrace = getStackTrace(t); String linebreak = SystemUtils.LINE_SEPARATOR; StringTokenizer frames = new StringTokenizer(stackTrace, linebreak); List list = new ArrayList(); boolean traceStarted = false; while (frames.hasMoreTokens()) { String token = frames.nextToken(); // Determine if the line starts with at int at = token.indexOf("at"); if (at != -1 && token.substring(0, at).trim().length() == 0) { traceStarted = true; list.add(token); } else if (traceStarted) { break; } } return list; } //----------------------------------------------------------------------- /** * Gets a short message summarising the exception. *

* The message returned is of the form * {ClassNameWithoutPackage}: {ThrowableMessage} * * @param th the throwable to get a message for, null returns empty string * @return the message, non-null * @since Commons Lang 2.2 */ public static String getMessage(Throwable th) { if (th == null) { return ""; } String clsName = ClassUtils.getShortClassName(th, null); String msg = th.getMessage(); return clsName + ": " + StringUtils.defaultString(msg); } //----------------------------------------------------------------------- /** * Gets a short message summarising the root cause exception. *

* The message returned is of the form * {ClassNameWithoutPackage}: {ThrowableMessage} * * @param th the throwable to get a message for, null returns empty string * @return the message, non-null * @since Commons Lang 2.2 */ public static String getRootCauseMessage(Throwable th) { Throwable root = ExceptionUtils.getRootCause(th); root = (root == null ? th : root); return getMessage(root); } }





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