- /* ====================================================================
- * The Apache Software License, Version 1.1
- *
- * Copyright (c) 2002-2003 The Apache Software Foundation. All rights
- * reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * 3. The end-user documentation included with the redistribution, if
- * any, must include the following acknowledgement:
- * "This product includes software developed by the
- * Apache Software Foundation (http://www.apache.org/)."
- * Alternately, this acknowledgement may appear in the software itself,
- * if and wherever such third-party acknowledgements normally appear.
- *
- * 4. The names "The Jakarta Project", "Commons", and "Apache Software
- * Foundation" must not be used to endorse or promote products derived
- * from this software without prior written permission. For written
- * permission, please contact apache@apache.org.
- *
- * 5. Products derived from this software may not be called "Apache"
- * nor may "Apache" appear in their names without prior written
- * permission of the Apache Software Foundation.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of the Apache Software Foundation. For more
- * information on the Apache Software Foundation, please see
- * <http://www.apache.org/>.
- */
- package org.apache.commons.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.LinkedList;
- import java.util.List;
- import java.util.StringTokenizer;
-
- import org.apache.commons.lang.ArrayUtils;
- import org.apache.commons.lang.StringUtils;
- import org.apache.commons.lang.SystemUtils;
-
- /**
- * <p>Provides utilities for manipulating and examining
- * <code>Throwable</code> objects.</p>
- *
- * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
- * @author Dmitri Plotnikov
- * @author Stephen Colebourne
- * @author <a href="mailto:ggregory@seagullsw.com">Gary Gregory</a>
- * @author Pete Gieser
- * @since 1.0
- * @version $Id: ExceptionUtils.java,v 1.34 2003/08/21 15:52:55 ggregory Exp $
- */
- public class ExceptionUtils {
-
- /**
- * <p>Used when printing stack frames to denote the start of a
- * wrapped exception.</p>
- *
- * <p>Package private for accessibility by test suite.</p>
- */
- static final String WRAPPED_MARKER = " [wrapped] ";
-
- /**
- * <p>The names of methods commonly used to access a wrapped exception.</p>
- */
- private static String[] CAUSE_METHOD_NAMES = {
- "getCause",
- "getNextException",
- "getTargetException",
- "getException",
- "getSourceException",
- "getRootCause",
- "getCausedByException",
- "getNested"
- };
-
- /**
- * <p>The Method object for JDK1.4 getCause.</p>
- */
- private static final Method THROWABLE_CAUSE_METHOD;
- static {
- Method getCauseMethod;
- try {
- getCauseMethod = Throwable.class.getMethod("getCause", null);
- } catch (Exception e) {
- getCauseMethod = null;
- }
- THROWABLE_CAUSE_METHOD = getCauseMethod;
- }
-
- /**
- * <p>Public constructor allows an instance of <code>ExceptionUtils</code>
- * to be created, although that is not normally necessary.</p>
- */
- public ExceptionUtils() {
- }
-
- //-----------------------------------------------------------------------
- /**
- * <p>Adds to the list of method names used in the search for <code>Throwable</code>
- * objects.</p>
- *
- * @param methodName the methodName to add to the list, <code>null</code>
- * and empty strings are ignored
- * @since 2.0
- */
- public static void addCauseMethodName(String methodName) {
- if (StringUtils.isNotEmpty(methodName)) {
- List list = new ArrayList(Arrays.asList(CAUSE_METHOD_NAMES));
- list.add(methodName);
- CAUSE_METHOD_NAMES = (String[]) list.toArray(new String[list.size()]);
- }
- }
-
- /**
- * <p>Introspects the <code>Throwable</code> to obtain the cause.</p>
- *
- * <p>The method searches for methods with specific names that return a
- * <code>Throwable</code> object. This will pick up most wrapping exceptions,
- * including those from JDK 1.4, and
- * {@link org.apache.commons.lang.exception.NestableException NestableException}.
- * The method names can be added to using {@link #addCauseMethodName(String)}.</p>
- *
- * <p>The default list searched for are:</p>
- * <ul>
- * <li><code>getCause()</code></li>
- * <li><code>getNextException()</code></li>
- * <li><code>getTargetException()</code></li>
- * <li><code>getException()</code></li>
- * <li><code>getSourceException()</code></li>
- * <li><code>getRootCause()</code></li>
- * <li><code>getCausedByException()</code></li>
- * <li><code>getNested()</code></li>
- * </ul>
- *
- * <p>In the absence of any such method, the object is inspected for a
- * <code>detail</code> field assignable to a <code>Throwable</code>.</p>
- *
- * <p>If none of the above is found, returns <code>null</code>.</p>
- *
- * @param throwable the throwable to introspect for a cause, may be null
- * @return the cause of the <code>Throwable</code>,
- * <code>null</code> if none found or null throwable input
- */
- public static Throwable getCause(Throwable throwable) {
- return getCause(throwable, CAUSE_METHOD_NAMES);
- }
-
- /**
- * <p>Introspects the <code>Throwable</code> to obtain the cause.</p>
- *
- * <ol>
- * <li>Try known exception types.</li>
- * <li>Try the supplied array of method names.</li>
- * <li>Try the field 'detail'.</li>
- * </ol>
- *
- * <p>A <code>null</code> set of method names means use the default set.
- * A <code>null</code> in the set of method names will be ignored.</p>
- *
- * @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 <code>Throwable</code>,
- * <code>null</code> if none found or null throwable input
- */
- public static Throwable getCause(Throwable throwable, String[] methodNames) {
- if (throwable == null) {
- return null;
- }
- Throwable cause = getCauseUsingWellKnownTypes(throwable);
- if (cause == null) {
- if (methodNames == null) {
- 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;
- }
-
- /**
- * <p>Introspects the <code>Throwable</code> to obtain the root cause.</p>
- *
- * <p>This method walks through the exception chain to the last element,
- * "root" of the tree, using {@link #getCause(Throwable)}, and
- * returns that exception.</p>
- *
- * @param throwable the throwable to get the root cause for, may be null
- * @return the root cause of the <code>Throwable</code>,
- * <code>null</code> if none found or null throwable input
- */
- public static Throwable getRootCause(Throwable throwable) {
- Throwable cause = getCause(throwable);
- if (cause != null) {
- throwable = cause;
- while ((throwable = getCause(throwable)) != null) {
- cause = throwable;
- }
- }
- return cause;
- }
-
- /**
- * <p>Finds a <code>Throwable</code> for known types.</p>
- *
- * <p>Uses <code>instanceof</code> checks to examine the exception,
- * looking for well known types which could contain chained or
- * wrapped exceptions.</p>
- *
- * @param throwable the exception to examine
- * @return the wrapped exception, or <code>null</code> 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;
- }
- }
-
- /**
- * <p>Finds a <code>Throwable</code> by method name.</p>
- *
- * @param throwable the exception to examine
- * @param methodName the name of the method to find and invoke
- * @return the wrapped exception, or <code>null</code> if not found
- */
- private static Throwable getCauseUsingMethodName(Throwable throwable, String methodName) {
- Method method = null;
- try {
- method = throwable.getClass().getMethod(methodName, null);
- } catch (NoSuchMethodException ignored) {
- } catch (SecurityException ignored) {
- }
-
- if (method != null && Throwable.class.isAssignableFrom(method.getReturnType())) {
- try {
- return (Throwable) method.invoke(throwable, ArrayUtils.EMPTY_OBJECT_ARRAY);
- } catch (IllegalAccessException ignored) {
- } catch (IllegalArgumentException ignored) {
- } catch (InvocationTargetException ignored) {
- }
- }
- return null;
- }
-
- /**
- * <p>Finds a <code>Throwable</code> by field name.</p>
- *
- * @param throwable the exception to examine
- * @param fieldName the name of the attribute to examine
- * @return the wrapped exception, or <code>null</code> if not found
- */
- private static Throwable getCauseUsingFieldName(Throwable throwable, String fieldName) {
- Field field = null;
- try {
- field = throwable.getClass().getField(fieldName);
- } catch (NoSuchFieldException ignored) {
- } catch (SecurityException ignored) {
- }
-
- if (field != null && Throwable.class.isAssignableFrom(field.getType())) {
- try {
- return (Throwable) field.get(throwable);
- } catch (IllegalAccessException ignored) {
- } catch (IllegalArgumentException ignored) {
- }
- }
- return null;
- }
-
- //-----------------------------------------------------------------------
- /**
- * <p>Checks if the Throwable class has a <code>getCause</code> method.</p>
- *
- * <p>This is true for JDK 1.4 and above.</p>
- *
- * @return true if Throwable is nestable
- * @since 2.0
- */
- public static boolean isThrowableNested() {
- return (THROWABLE_CAUSE_METHOD != null);
- }
-
- /**
- * <p>Checks whether this <code>Throwable</code> class can store a cause.</p>
- *
- * <p>This method does <b>not</b> check whether it actually does store a cause.<p>
- *
- * @param throwable the <code>Throwable</code> to examine, may be null
- * @return boolean <code>true</code> if nested otherwise <code>false</code>
- * @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();
- 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) {
- } catch (SecurityException ignored) {
- }
- }
-
- try {
- Field field = cls.getField("detail");
- if (field != null) {
- return true;
- }
- } catch (NoSuchFieldException ignored) {
- } catch (SecurityException ignored) {
- }
-
- return false;
- }
-
- //-----------------------------------------------------------------------
- /**
- * <p>Counts the number of <code>Throwable</code> objects in the
- * exception chain.</p>
- *
- * <p>A throwable without cause will return <code>1</code>.
- * A throwable with one cause will return <code>2</code> and so on.
- * A <code>null</code> throwable will return <code>0</code>.</p>
- *
- * @param throwable the throwable to inspect, may be null
- * @return the count of throwables, zero if null input
- */
- public static int getThrowableCount(Throwable throwable) {
- int count = 0;
- while (throwable != null) {
- count++;
- throwable = ExceptionUtils.getCause(throwable);
- }
- return count;
- }
-
- /**
- * <p>Returns the list of <code>Throwable</code> objects in the
- * exception chain.</p>
- *
- * <p>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 <code>null</code> throwable will return an array size zero.</p>
- *
- * @param throwable the throwable to inspect, may be null
- * @return the array of throwables, never null
- */
- public static Throwable[] getThrowables(Throwable throwable) {
- List list = new ArrayList();
- while (throwable != null) {
- list.add(throwable);
- throwable = ExceptionUtils.getCause(throwable);
- }
- return (Throwable[]) list.toArray(new Throwable[list.size()]);
- }
-
- //-----------------------------------------------------------------------
- /**
- * <p>Returns the (zero based) index of the first <code>Throwable</code>
- * that matches the specified type in the exception chain.</p>
- *
- * <p>A <code>null</code> throwable returns <code>-1</code>.
- * A <code>null</code> type returns <code>-1</code>.
- * No match in the chain returns <code>-1</code>.</p>
- *
- * @param throwable the throwable to inspect, may be null
- * @param type the type to search for
- * @return the index into the throwable chain, -1 if no match or null input
- */
- public static int indexOfThrowable(Throwable throwable, Class type) {
- return indexOfThrowable(throwable, type, 0);
- }
-
- /**
- * <p>Returns the (zero based) index of the first <code>Throwable</code>
- * that matches the specified type in the exception chain from
- * a specified index.</p>
- *
- * <p>A <code>null</code> throwable returns <code>-1</code>.
- * A <code>null</code> type returns <code>-1</code>.
- * No match in the chain returns <code>-1</code>.
- * A negative start index is treated as zero.
- * A start index greater than the number of throwables returns <code>-1</code>.</p>
- *
- * @param throwable the throwable to inspect, may be null
- * @param type the type to search for
- * @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 type, int fromIndex) {
- if (throwable == null) {
- return -1;
- }
- if (fromIndex < 0) {
- fromIndex = 0;
- }
- Throwable[] throwables = ExceptionUtils.getThrowables(throwable);
- if (fromIndex >= throwables.length) {
- return -1;
- }
- for (int i = fromIndex; i < throwables.length; i++) {
- if (throwables[i].getClass().equals(type)) {
- return i;
- }
- }
- return -1;
- }
-
- //-----------------------------------------------------------------------
- /**
- * <p>Prints a compact stack trace for the root cause of a throwable
- * to <code>System.err</code>.</p>
- *
- * <p>The compact 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.</p>
- *
- * <p>The method is equivalent to <code>printStackTrace</code> for throwables
- * that don't have nested causes.</p>
- *
- * @param throwable the throwable to output
- * @since 2.0
- */
- public static void printRootCauseStackTrace(Throwable throwable) {
- printRootCauseStackTrace(throwable, System.err);
- }
-
- /**
- * <p>Prints a compact stack trace for the root cause of a throwable.</p>
- *
- * <p>The compact 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.</p>
- *
- * <p>The method is equivalent to <code>printStackTrace</code> for throwables
- * that don't have nested causes.</p>
- *
- * @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 <code>null</code>
- * @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();
- }
-
- /**
- * <p>Prints a compact stack trace for the root cause of a throwable.</p>
- *
- * <p>The compact 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.</p>
- *
- * <p>The method is equivalent to <code>printStackTrace</code> for throwables
- * that don't have nested causes.</p>
- *
- * @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 <code>null</code>
- * @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();
- }
-
- //-----------------------------------------------------------------------
- /**
- * <p>Creates a compact stack trace for the root cause of the supplied
- * <code>Throwable</code>.</p>
- *
- * @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]);
- }
-
- /**
- * <p>Removes common frames from the cause trace given the two stack traces.</p>
- *
- * @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--;
- }
- }
-
- //-----------------------------------------------------------------------
- /**
- * <p>Gets the stack trace from a Throwable as a String.</p>
- *
- * @param throwable the <code>Throwable</code> to be examined
- * @return the stack trace as generated by the exception's
- * <code>printStackTrace(PrintWriter)</code> method
- */
- public static String getStackTrace(Throwable throwable) {
- StringWriter sw = new StringWriter();
- PrintWriter pw = new PrintWriter(sw, true);
- throwable.printStackTrace(pw);
- return sw.getBuffer().toString();
- }
-
- /**
- * <p>A way to get the entire nested stack-trace of an throwable.</p>
- *
- * @param throwable the <code>Throwable</code> 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();
- }
-
- //-----------------------------------------------------------------------
- /**
- * <p>Captures the stack trace associated with the specified
- * <code>Throwable</code> object, decomposing it into a list of
- * stack frames.</p>
- *
- * @param throwable the <code>Throwable</code> to exaamine, 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));
- }
-
- /**
- * <p>Functionality shared between the
- * <code>getStackFrames(Throwable)</code> methods of this and the
- * {@link org.apache.commons.lang.exception.NestableDelegate}
- * classes.</p>
- */
- static String[] getStackFrames(String stackTrace) {
- String linebreak = SystemUtils.LINE_SEPARATOR;
- StringTokenizer frames = new StringTokenizer(stackTrace, linebreak);
- List list = new LinkedList();
- while (frames.hasMoreTokens()) {
- list.add(frames.nextToken());
- }
- return (String[]) list.toArray(new String[list.size()]);
- }
-
- /**
- * <p>Produces a <code>List</code> of stack frames - the message
- * is not included.</p>
- *
- * <p>This works in most cases - it will only fail if the exception
- * message contains a line that starts with:
- * <code>" at".</code></p>
- *
- * @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 LinkedList();
- boolean traceStarted = false;
- while (frames.hasMoreTokens()) {
- String token = frames.nextToken();
- // Determine if the line starts with <whitespace>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;
- }
-
- }