de.susebox.java.lang

Interface ThrowableList

All Known Implementing Classes:

ExtIllegalArgumentException, ExtIndexOutOfBoundsException, ExtIOException, ExtNoSuchElementException, ExtNoSuchMethodException, ExtNullPointerException, ExtRuntimeException, ExtUnsupportedOperationException, TokenizerException

public interface ThrowableList

This interface should be implemented by classes derived from Throwable that may contain a stacked, additional or wrapped throwable.

Such cases are common when

• a method implements a certain interface method that allows for a specific throwable like IOException, but the method itself may encounter a different throwable type like SQLException (wrapped throwable)
• one application layer catches an throwable only to add its specific information in form of another throwable (throwable stack, nested throwable like in SQLException or MessagingException).

We provide the expected code in block comments starting with -->, terminated by -->. Note that the provided code also includes a new implementation of the base class method Throwable.getMessage() using the text formatting capabilities of MessageFormat.

Note: This interface replaces the formerly used ExceptionList interface.

Note: With JDK 1.4, the chained exception facility is available, that implements a Throwable stack (or list of causes) already in Throwable. Still, the notion of a wrapped exception and the delayed formatting is a reason for this interface.

Version:

1.00, 2001/06/26

Author:

Heiko Blau

Method Summary

Modifier and Type	Method and Description
java.lang.Object[]	getArguments() Retrieving the arguments for message formats.
java.lang.Throwable	getCause() Retrieving the cause of a Throwable.
java.lang.String	getFormat() Getting the format string of a throwable message.
boolean	isWrapper() Check if this is only a throwable that wraps the real one.
java.lang.Throwable	nextThrowable() Deprecated. use the JDK 1.4 call getCause() instead

Method Detail

getCause

java.lang.Throwable getCause()

Retrieving the cause of a Throwable. This is the method introduced with JDK 1.4. It replaces the older nextThrowable().

Returns:

the cause of this Throwable

See Also:

Throwable.getCause()

nextThrowable

java.lang.Throwable nextThrowable()

Deprecated. use the JDK 1.4 call getCause() instead

Method to traverse the throwable list. By convention, nextThrowable> returns the "earlier" throwable. By walking down the throwable list one gets the the following meaning:
this happened because nextThrowable happened because nextThrowable happened...
The next throwable has usually one of the following meaning:

• It is the "real" throwable. An interface implementation might be allowed to throw only IOException, but actually has to pass on a SQLException. That could be done by wrapping the SQLException into the IOException.
• The next throwable is "deeper" cause of this one (often called a nested throwable). A file couldn't be read in the first place and therefore not be attached to a mail. Both this throwable and the one nested inside have their own message.
There are more than one basic throwable to be propagated. A simple parser might return all syntax errors in one throwable list.

Returns:

the "earlier" throwable

isWrapper

boolean isWrapper()

Check if this is only a throwable that wraps the real one. This might be nessecary to pass an throwable incompatible to a method declaration.

Returns:

true if this is a wrapper throwable, false otherwise

getFormat

java.lang.String getFormat()

Getting the format string of a throwable message. This can also be the message itself if there are no arguments.

Returns:

the format string being used by MessageFormat

See Also:

getArguments()

getArguments

java.lang.Object[] getArguments()

Retrieving the arguments for message formats. These arguments are used by the MessageFormat.format(java.lang.Object[], java.lang.StringBuffer, java.text.FieldPosition) call.

Returns:

the arguments for a message format

See Also:

getFormat()