cn.com.sinosoft.util.exception.ExceptionUtils.java Source code

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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 compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/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 cn.com.sinosoft.util.exception;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
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 cn.com.sinosoft.lang.ArrayUtils;
import cn.com.sinosoft.lang.ClassUtils;
import cn.com.sinosoft.lang.NullArgumentException;
import cn.com.sinosoft.lang.SystemUtils;
import cn.com.sinosoft.util.string.StringUtils;

/**
 * <p>
 * Provides utilities for manipulating and examining <code>Throwable</code>
 * objects.
 * </p>
 * 
 * @author Apache Software Foundation
 * @author Daniel L. Rall
 * @author Dmitri Plotnikov
 * @author <a href="mailto:ggregory@seagullsw.com">Gary Gregory</a>
 * @author Pete Gieser
 * @since 1.0
 * @version $Id: ExceptionUtils.java 905837 2010-02-02 23:32:11Z niallp $
 */
@SuppressWarnings({ "rawtypes", "unchecked" })
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] ";

    // Lock object for CAUSE_METHOD_NAMES
    private static final Object CAUSE_METHOD_NAMES_LOCK = new Object();

    /**
     * <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",
            "getLinkedException", "getNestedException", "getLinkedCause", "getThrowable", };

    /**
     * <p>
     * The Method object for Java 1.4 getCause.
     * </p>
     */
    private static final Method THROWABLE_CAUSE_METHOD;

    /**
     * <p>
     * The Method object for Java 1.4 initCause.
     * </p>
     */
    private static final Method THROWABLE_INITCAUSE_METHOD;

    static {
        Method causeMethod;
        try {
            Class<?>[] parameterTypes = {};
            causeMethod = Throwable.class.getMethod("getCause", parameterTypes);
        } 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;
    }

    /**
     * <p>
     * Public constructor allows an instance of <code>ExceptionUtils</code> to
     * be created, although that is not normally necessary.
     * </p>
     */
    public ExceptionUtils() {
        super();
    }

    // -----------------------------------------------------------------------
    /**
     * <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) && !isCauseMethodName(methodName)) {
            List list = getCauseMethodNameList();
            if (list.add(methodName)) {
                synchronized (CAUSE_METHOD_NAMES_LOCK) {
                    CAUSE_METHOD_NAMES = toArray(list);
                }
            }
        }
    }

    /**
     * <p>
     * Removes from the list of method names used in the search for
     * <code>Throwable</code> objects.
     * </p>
     * 
     * @param methodName
     *            the methodName to remove from the list, <code>null</code> 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);
                }
            }
        }
    }

    /**
     * <p>
     * Sets the cause of a <code>Throwable</code> using introspection, allowing
     * source code compatibility between pre-1.4 and post-1.4 Java releases.
     * </p>
     * 
     * <p>
     * The typical use of this method is inside a constructor as in the
     * following example:
     * </p>
     * 
     * <pre>
     * import org.apache.commons.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);
     *    }
     * }
     * </pre>
     * 
     * @param target
     *            the target <code>Throwable</code>
     * @param cause
     *            the <code>Throwable</code> to set in the target
     * @return a <code>true</code> 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 <code>String[]</code>.
     * 
     * @param list
     *            a list to transform.
     * @return the given list as a <code>String[]</code>.
     */
    private static String[] toArray(List list) {
        return (String[]) list.toArray(new String[list.size()]);
    }

    /**
     * 
     * @param exception
     * @return exception stack trace as a String.
     */
    public static String exceptionToString(Exception exception) {
        ByteArrayOutputStream buf = new ByteArrayOutputStream();
        exception.printStackTrace(new PrintWriter(buf, true));
        String exceptionMessage = buf.toString();
        if (buf != null) {
            try {
                buf.close();
            } catch (IOException e1) {
            }
        }
        return exceptionMessage;
    }

    /**
     * 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));
        }
    }

    /**
     * <p>
     * Tests if the list of method names used in the search for
     * <code>Throwable</code> objects include the given name.
     * </p>
     * 
     * @param methodName
     *            the methodName to search in the list.
     * @return if the list of method names used in the search for
     *         <code>Throwable</code> 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;
        }
    }

    // -----------------------------------------------------------------------
    /**
     * <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
     * @since 1.0
     */
    public static Throwable getCause(Throwable throwable) {
        synchronized (CAUSE_METHOD_NAMES_LOCK) {
            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
     * @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;
    }

    /**
     * <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>
     * 
     * <p>
     * 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.
     * </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) {
        List list = getThrowableList(throwable);
        return (list.size() < 2 ? null : (Throwable) list.get(list.size() - 1));
    }

    /**
     * <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 {
            Class<?>[] parameterTypes = {};
            method = throwable.getClass().getMethod(methodName, parameterTypes);
        } 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;
    }

    /**
     * <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) {
            // 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;
    }

    // -----------------------------------------------------------------------
    /**
     * <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();
        synchronized (CAUSE_METHOD_NAMES_LOCK) {
            for (int i = 0, isize = CAUSE_METHOD_NAMES.length; i < isize; i++) {
                try {

                    Class<?>[] parameterTypes = {};
                    Method method = cls.getMethod(CAUSE_METHOD_NAMES[i], parameterTypes);
                    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;
    }

    // -----------------------------------------------------------------------
    /**
     * <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>
     * 
     * <p>
     * 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.
     * </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) {
        return getThrowableList(throwable).size();
    }

    /**
     * <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 of size zero.
     * </p>
     * 
     * <p>
     * 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.
     * </p>
     * 
     * @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()]);
    }

    /**
     * <p>
     * Returns the list of <code>Throwable</code> objects in the exception
     * chain.
     * </p>
     * 
     * <p>
     * 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
     * <code>null</code> throwable will return a list of size zero.
     * </p>
     * 
     * <p>
     * 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.
     * </p>
     * 
     * @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;
    }

    // -----------------------------------------------------------------------
    /**
     * <p>
     * Returns the (zero based) index of the first <code>Throwable</code> 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.
     * </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 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);
    }

    /**
     * <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.
     * Subclasses of the specified class do not match - see
     * {@link #indexOfType(Throwable, Class, int)} for the opposite.
     * </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 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);
    }

    // -----------------------------------------------------------------------
    /**
     * <p>
     * Returns the (zero based) index of the first <code>Throwable</code> 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.
     * </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, 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);
    }

    /**
     * <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.
     * Subclasses of the specified class do match - see
     * {@link #indexOfThrowable(Throwable, Class)} for the opposite.
     * </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, 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);
    }

    /**
     * <p>
     * Worker method for the <code>indexOfType</code> methods.
     * </p>
     * 
     * @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 <code>true</code>, compares with
     *            {@link Class#isAssignableFrom(Class)}, otherwise compares
     *            using references
     * @return index of the <code>type</code> within throwables nested withing
     *         the specified <code>throwable</code>
     */
    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;
    }

    // -----------------------------------------------------------------------
    /**
     * <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 output of this method is consistent across JDK versions. Note that
     * this is the opposite order to the JDK1.4 display.
     * </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 output of this method is consistent across JDK versions. Note that
     * this is the opposite order to the JDK1.4 display.
     * </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 output of this method is consistent across JDK versions. Note that
     * this is the opposite order to the JDK1.4 display.
     * </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>
     * 
     * <p>
     * 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.
     * </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>
     * A way to get the entire nested stack-trace of an throwable.
     * </p>
     * 
     * <p>
     * The result of this method is highly dependent on the JDK version and
     * whether the exceptions override printStackTrace or not.
     * </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>
     * Gets the stack trace from a Throwable as a String.
     * </p>
     * 
     * <p>
     * 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.
     * </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>
     * Captures the stack trace associated with the specified
     * <code>Throwable</code> object, decomposing it into a list of stack
     * frames.
     * </p>
     * 
     * <p>
     * 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.
     * </p>
     * 
     * @param throwable
     *            the <code>Throwable</code> 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));
    }

    // -----------------------------------------------------------------------
    /**
     * <p>
     * Returns an array where each element is a line from the argument.
     * </p>
     * 
     * <p>
     * The end of line is determined by the value of
     * {@link SystemUtils#LINE_SEPARATOR}.
     * </p>
     * 
     * <p>
     * Functionality shared between the <code>getStackFrames(Throwable)</code>
     * methods of this and the
     * {@link org.apache.commons.lang.exception.NestableDelegate} classes.
     * </p>
     * 
     * @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);
    }

    /**
     * <p>
     * Produces a <code>List</code> of stack frames - the message is not
     * included. Only the trace of the specified exception is returned, any
     * caused by trace is stripped.
     * </p>
     * 
     * <p>
     * This works in most cases - it will only fail if the exception message
     * contains a line that starts with:
     * <code>&quot;&nbsp;&nbsp;&nbsp;at&quot;.</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 ArrayList();
        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;
    }

    // -----------------------------------------------------------------------
    /**
     * Gets a short message summarising the exception.
     * <p>
     * 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.
     * <p>
     * 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);
    }

}