6.63 Exception

Defined in namespace Smalltalk

Category: Language-Exceptions

An Exception defines the characteristics of an exceptional event in a different way than CoreExceptions. Instead of creating an hierarchy of objects and setting attributes of the objects, you create an hierarchy of classes and override methods in those classes; instances of those classes are passed to the handlers instead of instances of the common class Signal.

Internally, Exception and every subclass of it hold onto a CoreException, so the two mechanisms are actually interchangeable.

6.63.1 Exception class: comparison		(class)
6.63.2 Exception class: creating ExceptionCollections		(class)
6.63.3 Exception class: initialization		(class)
6.63.4 Exception class: instance creation		(class)
6.63.5 Exception class: interoperability with TrappableEvents		(class)
6.63.6 Exception: comparison		(instance)
6.63.7 Exception: exception description		(instance)
6.63.8 Exception: exception signaling		(instance)

6.63.1 Exception class: comparison

handles: anException

Answer whether the receiver handles `anException'.

6.63.2 Exception class: creating ExceptionCollections

, aTrappableEvent

Answer an ExceptionCollection containing all the exceptions in the receiver and all the exceptions in aTrappableEvent

6.63.3 Exception class: initialization

initialize

Initialize the `links' between the core exception handling system and the ANSI exception handling system.

6.63.4 Exception class: instance creation

new

Create an instance of the receiver, which you will be able to signal later.

signal

Create an instance of the receiver, give it default attributes, and signal it immediately.

signal: messageText

Create an instance of the receiver, set its message text, and signal it immediately.

6.63.5 Exception class: interoperability with TrappableEvents

allExceptionsDo: aBlock

Private - Pass the coreException to aBlock

coreException

Private - Answer the coreException which represents instances of the receiver

whenSignalledIn: onDoBlock do: handlerBlock exitBlock: exitBlock

Private - Create an ExceptionHandler from the arguments and register it

6.63.6 Exception: comparison

= anObject

Answer whether the receiver is equal to anObject. This is true if either the receiver or its coreException are the same object as anObject.

hash

Answer an hash value for the receiver.

6.63.7 Exception: exception description

defaultAction

Execute the default action that is attached to the receiver.

description

Answer a textual description of the exception.

isResumable

Answer true. Exceptions are by default resumable.

6.63.8 Exception: exception signaling

signal

Raise the exceptional event represented by the receiver

signal: messageText

Raise the exceptional event represented by the receiver, setting its message text to messageText.