Package org.codehaus.plexus.util

Class ExceptionUtils

  • public class ExceptionUtils
extends Object

    ExceptionUtils provides utilities for manipulating Throwable objects.

    Since:
    1.0
    Author:
    Daniel Rall, Dmitri Plotnikov, Stephen Colebourne

    • Field Detail

      • CAUSE_METHOD_NAMES

        protected static String[] CAUSE_METHOD_NAMES
        The names of methods commonly used to access a wrapped exception.

    • Constructor Detail

      • ExceptionUtils

        protected ExceptionUtils()
        Constructs a new ExceptionUtils. Protected to discourage instantiation.

    • Method Detail

      • addCauseMethodName

        public static void addCauseMethodName​(String methodName)

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

        Parameters:
        methodName - the methodName to add to the list, null and empty strings are ignored

      • getCause

        public static Throwable getCause​(Throwable throwable)

        Introspects the specified 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 The method names can be added to using 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.

        Parameters:
        throwable - The exception to introspect for a cause.
        Returns:
        The cause of the Throwable.
        Throws:
        NullPointerException - if the throwable is null

      • getCause

        public static Throwable getCause​(Throwable throwable,
                                 String[] methodNames)

        Introspects the specified Throwable to obtain the cause using a supplied array of method names.

        Parameters:
        throwable - The exception to introspect for a cause.
        methodNames - the methods names to match
        Returns:
        The cause of the Throwable.
        Throws:
        NullPointerException - if the method names array is null or contains null
        NullPointerException - if the throwable is null

      • getRootCause

        public static Throwable getRootCause​(Throwable throwable)

        Walks through the exception chain to the last element -- the "root" of the tree -- using getCause(Throwable), and returns that exception.

        Parameters:
        throwable - the throwable to get the root cause for
        Returns:
        The root cause of the Throwable.

      • getThrowableCount

        public static int getThrowableCount​(Throwable throwable)

        Returns the number of Throwable objects in the exception chain.

        Parameters:
        throwable - the exception to inspect
        Returns:
        The throwable count.

      • getThrowables

        public static Throwable[] getThrowables​(Throwable throwable)

        Returns the list of Throwable objects in the exception chain.

        Parameters:
        throwable - the exception to inspect
        Returns:
        The list of Throwable objects.

      • indexOfThrowable

        public static int indexOfThrowable​(Throwable throwable,
                                   Class type,
                                   int fromIndex)

        Returns the (zero based) index, of the first Throwable that matches the specified type in the exception chain of Throwable objects with an index greater than or equal to the specified index, or -1 if the type is not found.

        Parameters:
        throwable - the exception to inspect
        type - Class to look for
        fromIndex - the (zero based) index of the starting position in the chain to be searched
        Returns:
        the first occurrence of the type in the chain, or -1 if the type is not found
        Throws:
        IndexOutOfBoundsException - If the fromIndex argument is negative or not less than the count of Throwables in the chain.

      • printRootCauseStackTrace

        public static void printRootCauseStackTrace​(Throwable t,
                                            PrintStream stream)
        Prints a compact stack trace for the root cause of a throwable. 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.

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

        Parameters:
        t - the exception
        stream - the stream

      • printRootCauseStackTrace

        public static void printRootCauseStackTrace​(Throwable t)
        Equivalent to printRootCauseStackTrace(t, System.err)
        Parameters:
        t - the exception

      • printRootCauseStackTrace

        public static void printRootCauseStackTrace​(Throwable t,
                                            PrintWriter writer)
        Same as printRootCauseStackTrace(t, stream), except it takes a PrintWriter as an argument.
        Parameters:
        t - the cause
        writer - the writer

      • getRootCauseStackTrace

        public static String[] getRootCauseStackTrace​(Throwable t)
        Creates a compact stack trace for the root cause of the supplied throwable. See printRootCauseStackTrace(Throwable t, PrintStream s)
        Parameters:
        t - the cause
        Returns:
        the Stack

      • getStackTrace

        public static String getStackTrace​(Throwable t)
        A convenient way of extracting the stack trace from an exception.
        Parameters:
        t - The Throwable.
        Returns:
        The stack trace as generated by the exception's printStackTrace(PrintWriter) method.

      • getFullStackTrace

        public static String getFullStackTrace​(Throwable t)
        A way to get the entire nested stack-trace of an throwable.
        Parameters:
        t - The Throwable.
        Returns:
        The nested stack trace, with the root cause first.

      • isNestedThrowable

        public static boolean isNestedThrowable​(Throwable throwable)
        Whether an Throwable is considered nested or not.
        Parameters:
        throwable - The Throwable.
        Returns:
        boolean true/false

      • getStackFrames

        public static String[] getStackFrames​(Throwable t)
        Captures the stack trace associated with the specified Throwable object, decomposing it into a list of stack frames.
        Parameters:
        t - The Throwable.
        Returns:
        An array of strings describing each stack frame.