Details
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Improvement
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Status: Closed
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Major
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Resolution: Fixed
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None
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None
Description
The specs (assembly and C&I) do not seem to be very explicit about what
should happen with an interface that is annotated as @Callback and that
defines more than one method. But notice that if this is the case then
the next question pertains to a previous question, which is what happens
when the callback interface (the one in the annotation, not the annotated
one) has more than one method.
Let i1 be an intrerface annotated with @Callback(c1), where c1 is the
callback interface. The simplest case is when both i1 and c1 have only
one method. If i1 has > 1 methods there are two cases: c1 has only one
method, and c1 has > 1 methods. The first case is the case at hand.
Notice that one last case is where i1 has one method and c1 has > 1, but
that really is a special case of the second case.
The second case is the one we had asked about before, how do we associate
methods in c1 with methods in i1. Again, the specs are not explicit about
this. In general, this association may require knowledge about the
implementation of i1. That is, i1Impl will get an injected instance of c1
which then it will use in its method(s) to make callback invocations.
Which c1 method is invoked in i1 is arbitrary and we may have to resort
to non-trivial introspection to figure it out. Btw, nontice that this
case also includes the first case.
So it seems we have a choice of how to interpret the specs.
1- The simplest choice is to assume i1 and c1 both have only one method.
2- We can assume that c1 has only one method (case at hand) and
introspect each method in i1 to figure out which is intended as async
with callback and which is not. In addition, here we also have a choice
of whether to treat non-callback methods as sync or async.
3- We can try go for the general case.
My vote is to go with choice 1, which is what I have been assuming so
far, at least for the coming release. And if we don't feel comfortable
with this choice long term, then we can try for choice 2 or maybe even
choice 3, if we can make sense of it.
It would also be useful to try to go back to the spec collaboration to
try to calrify the intent.
More details:
http://www.mail-archive.com/tuscany-dev%40ws.apache.org/msg08617.html