I would like to lift this discussion to a higher
level of abstraction, as Adam is trying to. What
are the actual requirements against the CAS? Here's
what I think I understood.
You want to be able to obtain from the CAS a marker
object. Then you want to be able to query the CAS
with the marker and an FS and ask if the FS was
added before or after the marker was obtained. Is
that right?
--Thilo
Bhavani Iyer wrote:
If we are thinking of Delta CAS in the context of service the largest xmi id
works. But
we were also using the same mechanism to support tracking CAS activity by
component.
I suppose in the second case the additional overhead of maintaining a list
of the FSs that
are added may be acceptable.
On Wed, Jul 9, 2008 at 3:48 PM, Adam Lally <[EMAIL PROTECTED]> wrote:
Back to the high-water mark ... isn't it just the largest xmi id in the
serialized CAS? Its relationship to the CAS heap is a matter of
implementation but presumably we can have a design that says any new FSs
must be given an xmi id above the high-water mark when serialized back
from
a service. We already have the requirement that ids must be preserved
for
the merging of parallel replies.
Yes - there are really two definitions of high-water mark floating
around in this thread and it would be good to split them apart.
(1) the largest xmi:id in the serialized CAS. This is a requirement
that the service protocol places on the CAS serializer. This is what
we already have for merging, and I don't think Thilo is objecting to
this.
(2) a dependency on the FS address being an indicator of which FS are
newer than others (an FS with a larger address is newer).
As I think about it now I am actually unclear on whether we are doing
#2 right now at all. Bhavani said we were, but that's not how I
recall that the serializer currently works. It keeps a table of all
the incoming FS, which is necessary in order to have the xmi:ids going
out be the same as the ones coming in. So I thought the serializer
just used the fact that an FS was missing from this table to determine
that it was new, and *not* a high water mark of the FS address.
Bhavani, can you clarify?
-Adam
