context sharing (issue 46)

["Mark Little" <mark.little@arjuna.com>]

Issue 46 (and a related issue from Peter Furniss) is about the concurrency control implications of allowing a mutable context to be shared, either when it is passed by reference or passed by value. To be honest, when writing the original specifications we deliberately didn't address this because it isn't easy (!) but also because I don't believe there's a clear solution. Maybe there will be in a couple of years once people start to use implementations of WS-Context once it becomes a standard, but at the moment I don't think it's clear cut.

 

My preference on this issue would be two fold:

 

a) explicitly mention this potential issue in the specification and leave it up to the implementation as to how (and if) it wants to tackle it,

 

and

 

b) add an "immutable" or "readonly" flag to the context schema (default could be true), which means that the context cannot be augmented by application-level Web services. All other augmentation happens by ALS-es under the control of the Context Service anyway.

 

Mark.

 

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Mark Little,
Chief Architect, Transactions,
Arjuna Technologies Ltd.
 
www.arjuna.com