RE: [wsbpel] the last paragraph of "Default Compensation Order" section

["Peter Furniss" <peter.furniss@erebor.co.uk>]

I'm having difficulty sorting out what this means - nothing particularly to do with transactionality, just whether two orderings are consistent

 

given a structure of scopes (with flows)

A

    B

        C

    D

        E

        F

 

and start-  -end times for the scopes

 

a-  b-  d- c- e- f- -e -c -f -d -b FAULT

 

then showing the start end of the compensation handlers, doesn't depth first do

  b- c- -c -b d- f- -f e- -e -d

 

but strict reverse is

 

oh - exactly the same (since I can't complete B.compensationHandler without doing C.compensationHandler.

 

How about adding at the end of the consistent sentence, and putting "would" in the last:

 

"The default compensation order mandated by the rules here is consistent with strict reverse order of completion within scopes at one level. Strict reverse order of completion applied to compensation
of all scopes may be not in depth-first order and would require interleaving of nested
compensations across peer scopes, which is not supported by this specification.

 

Peter

---

From: Alex Yiu [mailto:alex.yiu@oracle.com]
Sent: 04 May 2006 07:55
To: wsbpeltc
Cc: Alex Yiu
Subject: [wsbpel] the last paragraph of "Default Compensation Order" section

In the last paragraph of "Default Compensation Order" section, we have seemingly have two phrases that are seemingly difficult to be jelled together:
"... Rule 2 is to permit a depth-first traversal ..." and
"default compensation order mandated by the rules here is consistent with strict reverse order of completion, but not in depth-first order ..."
 
Here is an attempt to smooth this paragraph out:
----------------------
An effect of Rule 2 is to permit a depth-first traversal of the lexical scope tree for default
compensation, respecting the control dependency relation among peer scopes as dictated
by Rule 1. Since depth-first order implies that such compensation is only dependent on
the compensation of its nested scopes, default compensation order can be easily defined.
The default compensation order mandated by the rules here is consistent with strict
reverse order of completion. Strict reverse order of completion applied to compensation
of all scopes may be not in depth-first order and require interleaving of nested
compensations across peer scopes, which is not supported by this specification.
----------------------

(I attached the PDF and DOC version as well).
Let's see whether this text is accepted tomorrow.


Regards,
Alex Yiu