Declarative exception handling is a very welcome feature in struts b1, but
it receives very little comments. I put my little thought here and hope it will
help when b2 is coming out:
1. The 'scope' attribute in ExceptionConfig is possibly redundant.
According the current API doc, the 'scope' is to used to specify where
to store the ActionErrors resulted from this exception. But with a
careful examination of the machinery of the error handling and
propagation in both struts and tomcat, errors or exceptions if any,
*must* be resolved within life span of the request by either display
error messages back to users or log error messages, or something else.
there is almost no point to store ActionErrors in HttpSession.
2. There is a possibly missing attribute 'context relative' in ExceptionConfig
that describes the 'path' attribute needed when constructing
ActionForward in ExceptionHandler.execute(...) method.
Although the current API doc indicates that the 'path' is a context
relative path, the implementation the ExceptionHandler.execute() method
does not really build a context relative ActionForward. Would that be a bug?
My thought to have a 'context relative' attribute in the ExceptionConfig is to
enforce the developer to honor it when they are constructing the
ActionForward. The other benefit is for the tool users. If they see
context relative checkbox selected, they are sure they are going to have
the forward action behavior as expected. Otherwise, they would wonder how
developers implement it.
3. It would be very nice that ExceptionHandler has an attribute to hold the
reference to the ActionServlet instance.
Chuck and I once discussed the need to access non-default resource
bundles inside the ExceptionHandler.execute() method. In a bigger picture,
developers may also need to access some plugins, data sources, etc,
in the method. If the action servlet instance is set to the ExceptionHandler
right after its creation, the problem is resolved.
The above problems are not really bugs. They could be *fixed* in subclasses,
but they'd better belong to base class things, any thoughts?
Jing
