org.apache.isis.core.commons.exceptions

Class ExceptionUtils

java.lang.Object

org.apache.isis.core.commons.exceptions.ExceptionUtils

public class ExceptionUtils
extends Object

Provides utilities for manipulating and examining Throwable objects.

Since:

1.0

Version:

$Id: ExceptionUtils.java 594278 2007-11-12 19:58:30Z bayard $

Author:

Daniel L. Rall, Dmitri Plotnikov, Stephen Colebourne, Gary Gregory, Pete Gieser

Constructor Summary

Constructors

Constructor and Description
ExceptionUtils() Public constructor allows an instance of ExceptionUtils to be created, although that is not normally necessary.

Method Summary

Methods

Modifier and Type	Method and Description
static Throwable	getCause(Throwable throwable) Introspects the Throwable to obtain the cause.
static Throwable	getCause(Throwable throwable, String[] methodNames) Introspects the Throwable to obtain the cause.
static String	getFullStackTrace(Throwable throwable) A way to get the entire nested stack-trace of an throwable.
static List	getThrowableList(Throwable throwable) Returns the list of Throwable objects in the exception chain.
static Throwable[]	getThrowables(Throwable throwable) Returns the list of Throwable objects in the exception chain.
static boolean	isNestedThrowable(Throwable throwable) Checks whether this Throwable class can store a cause.
static boolean	isThrowableNested() Checks if the Throwable class has a getCause method.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ExceptionUtils

public ExceptionUtils()

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

Method Detail

getCause

public static Throwable getCause(Throwable throwable)

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 NestableException. 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 throwable to introspect for a cause, may be null

Returns:

the cause of the Throwable, null if none found or null throwable input

Since:

1.0

getCause

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

Introspects the Throwable to obtain the cause.

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

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

Parameters:

throwable - the throwable to introspect for a cause, may be null

methodNames - the method names, null treated as default set

Returns:

the cause of the Throwable, null if none found or null throwable input

Since:

1.0

isThrowableNested

public static boolean isThrowableNested()

Checks if the Throwable class has a getCause method.

This is true for JDK 1.4 and above.

Returns:

true if Throwable is nestable

Since:

2.0

isNestedThrowable

public static boolean isNestedThrowable(Throwable throwable)

Checks whether this Throwable class can store a cause.

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

Parameters:

throwable - the Throwable to examine, may be null

Returns:

boolean true if nested otherwise false

Since:

2.0

getThrowables

public static Throwable[] getThrowables(Throwable throwable)

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.

Parameters:

throwable - the throwable to inspect, may be null

Returns:

the array of throwables, never null

See Also:

getThrowableList(Throwable)

getThrowableList

public static List getThrowableList(Throwable throwable)

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.

Parameters:

throwable - the throwable to inspect, may be null

Returns:

the list of throwables, never null

Since:

Commons Lang 2.2

getFullStackTrace

public static String getFullStackTrace(Throwable throwable)

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.

Parameters:

throwable - the Throwable to be examined

Returns:

the nested stack trace, with the root cause first

Since:

2.0