Re: minimum protocol framework

[Mark Little <mcl@arjuna.com>]

I think I agree the possibility of the division of labour, but does this imply all the branches (participants ?) are equal ?

 

For a classic transaction, they are - each resource/subordinate has a veto and they all get the same final signal. The only exception is where something votes read-only, when (for most protocols) it is usually ignored thereafter.

 

For a cohesion, our use-cases have tended to include things which are distinct - some parts (atomic groups) within the cohesion may be vital to the overall purpose, others may be optional (any 2 from 5), others may have a preferred/backup relationship (cancel the second unless the first refuses). That means the coordinator must distinguish each of these to the control logic and send appropriate messages back to each.

There is nothing to stop you registering different participants with different sub-terminator logics. I think a cleaner model would be based on this, rather than try to clutter the coordination/control logic with lots of "if this then that", "if timeperiod elapsed then this", "relationship is", ... I would prefer to see coordination/control logic for each type, and then some "superior" that talks to each to get the job done. It makes reasoning about the overall logic easier and its subcomponents.

 

Mark.

 

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Dr. Mark Little (mark@arjuna.com)
Transactions Architect, HP Arjuna Labs
Phone +44 191 2064538
Fax   +44 191 2064203