Thoughts on issue BINDINGS-85

[Simon Holdsworth <simon_holdsworth@uk.ibm.com>]

My thoughts on issue BINDINGS-85, replace
deliveryMode by use of intents.

Interestingly the original proposed
resolution of the issue regarding the clash between deliveryMode and atLeastOnce
(BINDINGS-5) proposed that we drop deliveryMode.  The TC obviously
disagreed, given the eventual resolution was to keep deliveryMode and document
the clash.  However I can't see anywhere in the mailing list or minutes
where the position for removal was stated.

I don't think we would need new intents
to resolve this issue, the existing atLeastOnce and atMostOnce intents
would drive the setting of persistence of JMS messages, with atMostOnce
being non-persistent, and atLeastOnce/exactlyOnce being persistent.  I
can't think of any other case that would need explicit persistence setting
without the intent, and the original work that resulted in the definition
of the reliability intents took all that into account.

The functionality that we would lose
is that the deliveryMode can be specified per operation in the JMS binding,
whereas intents don't apply at the operation level (?).  Other than
that at the binding level the header and intents are interchangable.

One of my original concerns was over
consistency of setting JMS headers - having a mixture of configuration
properties and intents might be confusing, although we don't have a full
set of configuration properties anyway.  If we were to remove deliveryMode,
we should look at the other headers, time to live and priority however
these are multi-valued, and so I'm not sure that they could be replaced
by intents.

Regards, Simon

Simon Holdsworth
STSM, SCA Bindings Architect; Master Inventor; OASIS SCA Bindings TC Chair
MP 211, IBM UK Labs, Hursley Park, Winchester SO21 2JN, UK
Tel +44-1962-815059 (Internal 245059) Fax +44-1962-816898
Internet - Simon_Holdsworth@uk.ibm.com

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