ABAP OO - Exceptions & Events

Question

Hello all:
Two questions specific to ABAP OO world:
1. Is anyone using "RAISE EXCEPTION TYPE exception-class" to raise business process errors (e.g. a customer is not found, or a sales order number is invalid, which originally was referred using ABAP Message Class (transaciton SE91)), Or are you keeping the 'RAISE EXCEPTION TYPE exception-class' limited only to raise and handle global level errors like (CAST_ERROR, TYPE_CONVERSION_ERROR, etc)?
2. Class Method M1 of class C1 raises event E1.
   Class Method M2 of class C2 handles the event E1.
   In method M1, is it possible to check - immediately
   after the statement that raises event E1 - whether the
   execution of M2 was successful? If yes, can you please
   briefly describe how we can achieve that.
Thanks!

Answer 1

In my personal opinion all errors that make the further regular processing within a certain context impossible, should raise an exception.
The problem with the message statement is, that if a function throws out dialog messages at the user, you can't use it as an API anymore, because if errors occur, the caller of your function cannot intercept the message anymore.
Of course on may use "message raising" but the use is a bit awkward and the especially if the caller decides propagate the error messages of the funtion that was called, it has to use these sy-msgid and all these Variables.
An Exception can also have an error text associated to it and in 640 an exception class may have an old-fashioned message class associated with it.
As error handling with try/catch has advantages (you may treat similar errors of a whole related block in one piece of code, error messages will be handed on to the caller, the compiler will check, if the error is taken care of), in my opinion all application-level errors should use exception classes. An exception class should be created for each type of error that can occur.
Exception classes can also be derived from each other, thus forming a hierarchy of errors. The caller may then even decide, if all errors of a certain "family" are treated equally, or if more specific checks are done, based on the specific type of exception.
For bringing up error messages to the user, you can get the exception's text and output it via message, if the error has really been propagated to a level of the application that is clearly dialogue-related.
This model is in my opinion much superior to the earlier error handling model.
Hope that helps.
Yours
Christian