org.apache.commons.io
Class TaggedIOException

java.lang.Object
  java.lang.Throwable
      java.lang.Exception
          java.io.IOException
              org.apache.commons.io.IOExceptionWithCause
                  org.apache.commons.io.TaggedIOException

All Implemented Interfaces:

java.io.Serializable

public class TaggedIOException
extends IOExceptionWithCause

An IOException decorator that adds a serializable tag to the wrapped exception. Both the tag and the original exception can be used to determine further processing when this exception is caught.

Since:

2.0

See Also:

Serialized Form

Field Summary

private static long	serialVersionUID Generated serial version UID.
private java.io.Serializable	tag The tag of this exception.

Constructor Summary

TaggedIOException(java.io.IOException original, java.io.Serializable tag)
Creates a tagged wrapper for the given exception.

Method Summary

java.io.IOException	getCause() Returns the wrapped exception.
java.io.Serializable	getTag() Returns the serializable tag object.
static boolean	isTaggedWith(java.lang.Throwable throwable, java.lang.Object tag) Checks whether the given throwable is tagged with the given tag.
static void	throwCauseIfTaggedWith(java.lang.Throwable throwable, java.lang.Object tag) Throws the original IOException if the given throwable is a TaggedIOException decorator the given tag.

Methods inherited from class java.lang.Throwable

fillInStackTrace, getLocalizedMessage, getMessage, getStackTrace, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

Generated serial version UID.

See Also:

Constant Field Values

tag

private final java.io.Serializable tag

The tag of this exception.

Constructor Detail

TaggedIOException

public TaggedIOException(java.io.IOException original,
                         java.io.Serializable tag)

Creates a tagged wrapper for the given exception.

Parameters:

original - the exception to be tagged

tag - tag of this exception

Method Detail

isTaggedWith

public static boolean isTaggedWith(java.lang.Throwable throwable,
                                   java.lang.Object tag)

Checks whether the given throwable is tagged with the given tag.

This check can only succeed if the throwable is a TaggedIOException and the tag is Serializable, but the argument types are intentionally more generic to make it easier to use this method without type casts.

A typical use for this method is in a catch block to determine how a caught exception should be handled:

 Serializable tag = ...;
 try {
     ...;
 } catch (Throwable t) {
     if (TaggedIOExcepton.isTaggedWith(t, tag)) {
         // special processing for tagged exception
     } else {
         // handling of other kinds of exceptions
     }
 }
 

Parameters:

throwable - The Throwable object to check

tag - tag object

Returns:

true if the throwable has the specified tag, otherwise false

throwCauseIfTaggedWith

public static void throwCauseIfTaggedWith(java.lang.Throwable throwable,
                                          java.lang.Object tag)
                                   throws java.io.IOException

Throws the original IOException if the given throwable is a TaggedIOException decorator the given tag. Does nothing if the given throwable is of a different type or if it is tagged with some other tag.

This method is typically used in a catch block to selectively rethrow tagged exceptions.

 Serializable tag = ...;
 try {
     ...;
 } catch (Throwable t) {
     TaggedIOExcepton.throwCauseIfTagged(t, tag);
     // handle other kinds of exceptions
 }
 

Parameters:

throwable - an exception

tag - tag object

Throws:

java.io.IOException - original exception from the tagged decorator, if any

getTag

public java.io.Serializable getTag()

Returns the serializable tag object.

Returns:

tag object

getCause

public java.io.IOException getCause()

Returns the wrapped exception. The only difference to the overridden Throwable.getCause() method is the narrower return type.

Overrides:

getCause in class java.lang.Throwable

Returns:

wrapped exception