ExceptionUtils (Apache Maven 4.0.0-alpha-2 API)

java.lang.Object
- org.codehaus.plexus.util.ExceptionUtils

```
public class ExceptionUtils
extends Object
```
ExceptionUtils provides utilities for manipulating Throwable objects.

Since:

1.0

Author:

Daniel Rall, Dmitri Plotnikov, Stephen Colebourne

Field Summary

Fields
Modifier and Type Field and Description

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

Fields
Modifier and Type	Field and Description
`protected static String[]`	`CAUSE_METHOD_NAMES` The names of methods commonly used to access a wrapped exception.

Constructor Summary

Constructors
Modifier Constructor and Description

protected ExceptionUtils()
Constructs a new ExceptionUtils.

Constructors
Modifier	Constructor and Description
`protected`	`ExceptionUtils()` Constructs a new `ExceptionUtils`.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static void`	`addCauseMethodName(String methodName)` Adds to the list of method names used in the search for `Throwable` objects.
`static Throwable`	`getCause(Throwable throwable)` Introspects the specified `Throwable` to obtain the cause.
`static Throwable`	`getCause(Throwable throwable, String[] methodNames)` Introspects the specified `Throwable` to obtain the cause using a supplied array of method names.
`static String`	`getFullStackTrace(Throwable t)` A way to get the entire nested stack-trace of an throwable.
`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.
`static String[]`	`getRootCauseStackTrace(Throwable t)` Creates a compact stack trace for the root cause of the supplied throwable.
`static String[]`	`getStackFrames(Throwable t)` Captures the stack trace associated with the specified `Throwable` object, decomposing it into a list of stack frames.
`static String`	`getStackTrace(Throwable t)` A convenient way of extracting the stack trace from an exception.
`static int`	`getThrowableCount(Throwable throwable)` Returns the number of `Throwable` objects in the exception chain.
`static Throwable[]`	`getThrowables(Throwable throwable)` Returns the list of `Throwable` objects in the exception chain.
`static int`	`indexOfThrowable(Throwable throwable, Class type)` Delegates to `indexOfThrowable(Throwable, Class, int)`, starting the search at the beginning of the exception chain.
`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.
`static boolean`	`isNestedThrowable(Throwable throwable)` Whether an Throwable is considered nested or not.
`static void`	`printRootCauseStackTrace(Throwable t)` Equivalent to printRootCauseStackTrace(t, System.err)
`static void`	`printRootCauseStackTrace(Throwable t, PrintStream stream)` Prints a compact stack trace for the root cause of a throwable.
`static void`	`printRootCauseStackTrace(Throwable t, PrintWriter writer)` Same as printRootCauseStackTrace(t, stream), except it takes a PrintWriter as an argument.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 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)
```
    Delegates to indexOfThrowable(Throwable, Class, int), starting the search at the beginning of the exception chain.
    
    Parameters:
    
    throwable - the exception to inspect
    
    type - Class to look for
    
    Returns:
    
    index of the stack matching the type
    
    See Also:
    
    indexOfThrowable(Throwable, Class, int)
  - 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.

Class ExceptionUtils

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

CAUSE_METHOD_NAMES

Constructor Detail

ExceptionUtils

Method Detail

addCauseMethodName

getCause

getCause

getRootCause

getThrowableCount

getThrowables

indexOfThrowable

indexOfThrowable

printRootCauseStackTrace

printRootCauseStackTrace

printRootCauseStackTrace

getRootCauseStackTrace

getStackTrace

getFullStackTrace

isNestedThrowable

getStackFrames