Re: [wsbpel] Q: Location of rethrow

["Yaron Y. Goland" <ygoland@bea.com>]

This is a create catch, all puns intended. Minimally Yuzo you should 
file an issue on this in order to get a clarification into the spec.

I think the answer is that whenever a fault handler is entered one can 
conceptually think of a state variable being associated with that fault 
handler that records the current fault. When rethrow is called it is a 
copy of the fault in the state variable that is rethrown.

So, using your original example:
    faulthandlers
       catch name="FH1" faultName="x:foo"
          sequence
             ...
             scope
                faulthandlers
                   catch name="FH2" faultName="x:foo"
                      ...
                rethrow

The rethrow would rethrow the fault caught by FH1 and it would be caught 
by FH2.

My reasoning for this behavior is that rethrow was intended as a way to 
allow programs to rethrow faults whose name and/or content they were not 
aware of. So there is nothing 'magical' about rethrow, it just blindly 
rethrows whatever fault is in 'scope'. In the example above the fault 
that is 'in scope' is the one caught by FH1.

By contrast:

    faulthandlers
       catch name="FH1" faultName="x:foo"
          sequence
             ...
             scope
                faulthandlers
                   catch name="FH2" faultName="x:foo"
                      ...
                      rethrow
                ...

In the previous example the fault that will be rethrown is the one that 
is caught by FH2. Note, however that the rethrown fault will NOT be 
caught by FH1. The reason being that once a scope has thrown a fault and 
a fault handler has caught it all of the scope's remaining fault 
handlers are removed. Therefore the fault rethrown in the example above 
would be caught by some unnamed parent scope.

		Yaron


Yuzo Fujishima wrote:

> 
> 
> Hi,
> 
> I have a question regarding where we can place <rethrow>.
> 
> The current specification says:
>   <rethrow> activity can be used ONLY within a fault handler
>   (i.e. <catch> and <catchAll> elements).
> 
> Therefore, I think the following is legal:
>   <faulthandlers>
>     <catch name="FH1" faultName="x:foo">
>       <sequence>
>         ...
>         <rethrow/>
>       </sequence>
>     </catch>
>   </faultHandlers>
> 
> But I am not sure about the following:
> 
>   <faulthandlers>
>     <catch name="FH1" faultName="x:foo">
>       <sequence>
>         ...
>         <scope>
>           <faulthandlers>
>             <catch name="FH2" faultName="x:foo">
>             ...
>             </catch>
>           </faultHandlers>
>           <rethrow/>
>         </scope>
>       </sequence>
>     </catch>
>   </faultHandlers>
> 
> Q1: Is it legal to place the <rethrow> there?
> 
> Q2: Assuming the answer to Q1 is yes,
>     will FH2 catch the rethrown fault?
> 
> Yuzo Fujishima
> NEC Corporation
> 
> 
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> 
>  From - Fri