org.apache.commons.lang.exception
Class NestableDelegate

java.lang.Object
  extended byorg.apache.commons.lang.exception.NestableDelegate
All Implemented Interfaces:
java.io.Serializable

public class NestableDelegate
extends java.lang.Object
implements java.io.Serializable

A shared implementation of the nestable exception functionality.

The code is shared between NestableError, NestableException and NestableRuntimeException.

Since:
1.0
Version:
$Id: NestableDelegate.java 512889 2007-02-28 18:18:20Z dlr $
Author:
Rafal Krzewski, Daniel L. Rall, Kasper Nielsen, Steven Caswell, Sean C. Sullivan, Stephen Colebourne
See Also:
Serialized Form

Field Summary
static boolean matchSubclasses
          Whether to match subclasses via indexOf.
static boolean topDown
          Whether to print the stack trace top-down.
static boolean trimStackFrames
          Whether to trim the repeated stack trace.
 
Constructor Summary
NestableDelegate(Nestable nestable)
          Constructs a new NestableDelegate instance to manage the specified Nestable.
 
Method Summary
 java.lang.String getMessage(int index)
          Returns the error message of the Throwable in the chain of Throwables at the specified index, numbered from 0.
 java.lang.String getMessage(java.lang.String baseMsg)
          Returns the full message contained by the Nestable and any nested Throwables.
 java.lang.String[] getMessages()
          Returns the error message of this and any nested Throwables in an array of Strings, one element for each message.
protected  java.lang.String[] getStackFrames(java.lang.Throwable t)
          Captures the stack trace associated with the specified Throwable object, decomposing it into a list of stack frames.
 java.lang.Throwable getThrowable(int index)
          Returns the Throwable in the chain of Throwables at the specified index, numbered from 0.
 int getThrowableCount()
          Returns the number of Throwables contained in the Nestable contained by this delegate.
 java.lang.Throwable[] getThrowables()
          Returns this delegate's Nestable and any nested Throwables in an array of Throwables, one element for each Throwable.
 int indexOfThrowable(java.lang.Class type, int fromIndex)
          Returns the index, numbered from 0, of the first Throwable that matches the specified type, or a subclass, in the chain of Throwables with an index greater than or equal to the specified index.
 void printStackTrace()
          Prints the stack trace of this exception the the standar error stream.
 void printStackTrace(java.io.PrintStream out)
          Prints the stack trace of this exception to the specified stream.
 void printStackTrace(java.io.PrintWriter out)
          Prints the stack trace of this exception to the specified writer.
protected  void trimStackFrames(java.util.List stacks)
          Trims the stack frames.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

topDown

public static boolean topDown
Whether to print the stack trace top-down. This public flag may be set by calling code, typically in initialisation. This exists for backwards compatability, setting it to false will return the library to v1.0 behaviour (but will affect all users of the library in the classloader).

Since:
2.0

trimStackFrames

public static boolean trimStackFrames
Whether to trim the repeated stack trace. This public flag may be set by calling code, typically in initialisation. This exists for backwards compatability, setting it to false will return the library to v1.0 behaviour (but will affect all users of the library in the classloader).

Since:
2.0

matchSubclasses

public static boolean matchSubclasses
Whether to match subclasses via indexOf. This public flag may be set by calling code, typically in initialisation. This exists for backwards compatability, setting it to false will return the library to v2.0 behaviour (but will affect all users of the library in the classloader).

Since:
2.1
Constructor Detail

NestableDelegate

public NestableDelegate(Nestable nestable)
Constructs a new NestableDelegate instance to manage the specified Nestable.

Parameters:
nestable - the Nestable implementation (must extend Throwable)
Since:
2.0
Method Detail

getMessage

public java.lang.String getMessage(int index)
Returns the error message of the Throwable in the chain of Throwables at the specified index, numbered from 0.

Parameters:
index - the index of the Throwable in the chain of Throwables
Returns:
the error message, or null if the Throwable at the specified index in the chain does not contain a message
Throws:
java.lang.IndexOutOfBoundsException - if the index argument is negative or not less than the count of Throwables in the chain
Since:
2.0

getMessage

public java.lang.String getMessage(java.lang.String baseMsg)
Returns the full message contained by the Nestable and any nested Throwables.

Parameters:
baseMsg - the base message to use when creating the full message. Should be generally be called via nestableHelper.getMessage(super.getMessage()), where super is an instance of Throwable.
Returns:
The concatenated message for this and all nested Throwables
Since:
2.0

getMessages

public java.lang.String[] getMessages()
Returns the error message of this and any nested Throwables in an array of Strings, one element for each message. Any Throwable not containing a message is represented in the array by a null. This has the effect of cause the length of the returned array to be equal to the result of the getThrowableCount() operation.

Returns:
the error messages
Since:
2.0

getThrowable

public java.lang.Throwable getThrowable(int index)
Returns the Throwable in the chain of Throwables at the specified index, numbered from 0.

Parameters:
index - the index, numbered from 0, of the Throwable in the chain of Throwables
Returns:
the Throwable
Throws:
java.lang.IndexOutOfBoundsException - if the index argument is negative or not less than the count of Throwables in the chain
Since:
2.0

getThrowableCount

public int getThrowableCount()
Returns the number of Throwables contained in the Nestable contained by this delegate.

Returns:
the throwable count
Since:
2.0

getThrowables

public java.lang.Throwable[] getThrowables()
Returns this delegate's Nestable and any nested Throwables in an array of Throwables, one element for each Throwable.

Returns:
the Throwables
Since:
2.0

indexOfThrowable

public int indexOfThrowable(java.lang.Class type,
                            int fromIndex)
Returns the index, numbered from 0, of the first Throwable that matches the specified type, or a subclass, in the chain of Throwables with an index greater than or equal to the specified index. The method returns -1 if the specified type is not found in the chain.

NOTE: From v2.1, we have clarified the Nestable interface such that this method matches subclasses. If you want to NOT match subclasses, please use ExceptionUtils.indexOfThrowable(Throwable, Class, int) (which is avaiable in all versions of lang). An alternative is to use the public static flag matchSubclasses on NestableDelegate, however this is not recommended.

Parameters:
type - the type to find, subclasses match, null returns -1
fromIndex - the index, numbered from 0, of the starting position in the chain to be searched
Returns:
index of the first occurrence of the type in the chain, or -1 if the type is not found
Throws:
java.lang.IndexOutOfBoundsException - if the fromIndex argument is negative or not less than the count of Throwables in the chain
Since:
2.0

printStackTrace

public void printStackTrace()
Prints the stack trace of this exception the the standar error stream.


printStackTrace

public void printStackTrace(java.io.PrintStream out)
Prints the stack trace of this exception to the specified stream.

Parameters:
out - PrintStream to use for output.
See Also:
printStackTrace(PrintWriter)

printStackTrace

public void printStackTrace(java.io.PrintWriter out)
Prints the stack trace of this exception to the specified writer. If the Throwable class has a getCause method (i.e. running on jre1.4 or higher), this method just uses Throwable's printStackTrace() method. Otherwise, generates the stack-trace, by taking into account the 'topDown' and 'trimStackFrames' parameters. The topDown and trimStackFrames are set to 'true' by default (produces jre1.4-like stack trace).

Parameters:
out - PrintWriter to use for output.

getStackFrames

protected java.lang.String[] getStackFrames(java.lang.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.
Since:
2.0

trimStackFrames

protected void trimStackFrames(java.util.List stacks)
Trims the stack frames. The first set is left untouched. The rest of the frames are truncated from the bottom by comparing with one just on top.

Parameters:
stacks - The list containing String[] elements
Since:
2.0


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