Re: NEW ISSUE :Clarify usage of assertions with no behavioral requirements on the requeste

Re: NEW ISSUE: New Attribute keyword to identify 'local' policies #3721Hello,

This is the resolution I think would adequately address this issue :

1. Add an example to a primer and/or policy guidelines
2. Explain why policy authors should make such assertions optional for those requesters which are not aware of them. 
3. Make any necessary changes to the wsp:optional related wording so that a policy author can use wsp:optional as a recognized but not a workaround way to mark such assertions.

Thanks, Sergey

  Target : WS-Policy Framework and policy guidelines

  Justification :

  There's a class of policy assertions which have no behavioral requirements on the requester but can be still usefully processed by 
  requesters which are aware
  of what assertions mean.
  For example : <oasis:Replicatable/>

  An assertion like this one can be a useful source of information for requesters. Providers having expected properties like 
  <oasis:Replicatable/> can be chosen/searched.
  At the same time, given the fact assertions like <oasis:Replicatable/>
  have no behavioral requirements on the provider it's important to ensure
  policy-aware clients which have no knowledge of these assertions can proceed
  consuming the service advertsing this assertion.

  Currently the way to advertise such an assertion is to use a normal form with two policy alternatives(simple case), with only one 
  alternative containing this assertion thus making it optional, or, in other words, giving a chance to requesters to ignore it.
  Such normal form expression is equivalent to a compact form with the optional assertion marked with wsp:optional attribute with a 
  value 'true'.

  However, at the moment the primer recommends using wsp:optional when one needs to mark asssertions which identify optional 
  capabilities/requirements with behavioral requirements on a requester should the requester wishes to use it.

  Thus marking assertions like <oasis:Replicatable/> with wsp:optional is considered to be a wrong approach.

  Proposal :

  Clarify the text describing the optionality in the policy guidelines and in the Framework spec on how a policy author should use 
  assertions like
  It's important that assertions like these can be usefully interpreted by knowledgeble requesters and safely ignored by requesters 
  unaware of them. 

Received on Friday, 6 October 2006 10:25:37 UTC