Hi Yaron,
Assuming that we take Satish's interpretation that we allow a partial
termination of a <scope>. That is, NOT forcing using
<scope> within a <flow> with a completionCondition.
If I read the termination part of spec correctly and understand
Satish's interpretation of the spec, the compensationHandlers under the
while will NOT be lost. Let me put more words to illustrate what I
expect:
--------------------------------
scope name="A"
flow
completionCondition ...
...
while
scope
name="C"
compensationHandler
...
...
sequence name="done"
...
--------------------------------
Say the while loop execute from 1 to 10. During the execution of loop
#4, the sequence of name "done" triggers the early completion
condition. Hence, a termination happens to <while> loop.
The scope #1, #2, #3 (of name="C") got successfully executed. The
compensationHandlers are installed for these 3 scopes. The scope #4 got
terminated and its terminationHandler got triggered. Again, as we allow
a partial termination, the compensationHandler of the first 3 scopes
will remain untouched. They will be available to the scope-A to call,
if needed in the compensationHandler or faultHandler of scope-A.
On the other hand, if one puts a scope-B around <while>-activity
and within the <flow>. The termination/compensation will be
different.
--------------------------------
scope name="A"
flow
completionCondition ...
...
scope name="B"
while
scope
name="C"
compensationHandler
...
...
sequence name="done"
...
--------------------------------
The scope #1, #2, #3 (of name="C") got successfully executed. The
compensationHandlers are installed for these 3 scopes.
After the completionCondition is triggered, whe whole scope-B is being
terminated. The termination of scope-B will involve two parts:
cascade the termination to scope #4 (Hence, its
terminationHandler got triggered).
invoke the compensation handlers of scope #1, #2, #3.
In this case, the whole scope-B got terminated. So, the compensation
handlers of scope #1, #2, #3 will NOT be available to the scope-A to
call. Please note: this semantic has NOTHING to do with early
completion logic. It just shows a scope works today.
I believe that once we incorporate Satish's interpretation and
clarification about the possibility of a partial termination of a
scope. Then, this proposal would provide crispy clear picture and
foundation on how an early completion would work in BPEL. And, we
should be ready to go for the formal voting.
Thanks!
Regards,
Alex Yiu
Yaron Y. Goland wrote:
Imagine the
following sample code:
flow
completionCondition ...
...
while
scope
compensationHandler
...
...
sequence name="done"
...
Now imagine that the "done" sequence completes triggering the
completion condition and terminated the while. But the while had
already completed a few iterations and instantiated a number of
compensation handlers. What happens to those handlers?
Using the current termination language those handlers would be lost
when the parent scope is terminated. I suspect most programmers would
find this behavior to be surprising.
Yaron
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