Re: activity context

I am a fan of context and by having one for *all* 
  interactions, we can promote more of the stateless services. Here are 
  some of my thoughts on context:

Yes, it would be good if we could make progress on the context format. 
The basic structure could pass common features (such as the coordinator 
reference, timeout etc) in a strongly types fashion, and we can then allow model 
specific data in a less strongly typed manner (e.g., a CORBA any in the 
example), because any user of that data must check the type structure of the 
context anyway.

  
    1.    Context could be viewed as a set of 
  attribute assertions, some of them signed and even 
  encrypted.

Agreed. There's nothing to say that the model specific data couldn't be 
encrypted, for example.

  
    2.    Context is information other than 
  the actual transaction data and can include the user credentials, any previous 
  state, time of day, geographic location of the calling entity, 
  ...

I think that the general context should be a series of specific context 
instances, one for transactions (which only talks about transaction related 
stuff), one for security, etc.

  
    3.    The context of course would be an 
  XML document. I was thinking of something like :

  
        
  <context>

  
            
  <actionType>xxxx</actionType>

  
            
  ..

  
        
  </context>

  
    4.   Yes, context need not be that 
  elaborate, but we do need to divide context into related graphs so that 
  later the systems can use XPath/XPointer to get specific set of information 
  they need.

  
 

  
    5.    FYI, I think context is much more 
  important from a web services point-of-view and if W3C ever standardized the 
  context, we could use it at that time. For now we should be able to define a 
  simple context graph which is relevant to our 
work.

Agreed. Do you know where the W3C is with this at the 
moment?

  
    6.    If we start defining context 
  now,  i.e. what pieces of data do we need , we could "normalize" the 
  structure after we have identified say 70% of the 
  information.

All the best,

 

Mark.

 

----------------------------------------------
Dr. 
Mark Little ()
Transactions Architect, HP 
Arjuna Labs
Phone +44 191 2064538
Fax   +44 191 
2064203