ISSUE 31: Wiring from a reference with no binding to a service with a binding

[Scott Vorthmann <scottv@tibco.com>]

http://www.osoa.org/jira/browse/ASSEMBLY-31


On Nov 27, 2007, at 7:42 AM, Mike Edwards wrote:

>
> <This issue is transferred from the SCA Policy TC where it was  
> dubbed POLICY-34>
>
> RAISER  Michael Rowley (original)
>
> TARGET:  SCA Assembly Specification
>
> DESCRIPTION:
>
> The algorithm in the policy spec says that it is _not_ possible to  
> wire from a reference that does not declare a binding (i.e. uses  
> binding.sca) to a service that declares one or more bindings.  
> However, I think this should be possible.
>
> It is an unreasonable requirement to say that a service with a  
> binding can only be the target of a reference that has that same  
> binding. The default binding (binding.sca) should be treated as the  
> "I don't care" binding, and should work with any binding available  
> within the domain. Or, more precisely, any binding that can satisfy  
> the required intents.
>
> Section 4.8.1 of  the Policy frmework spec states:
>
> The wiring compatibility algorithm below determines the  
> compatibility of a wire by a pairwise choice of a binding instance  
> and the corresponding policySets on each side of the wire.
>
> This should be changed to the following:
>
> If either side of a wire does not specify a binding (or explicitly  
> specifies binding.sca) the wire is considered to be valid for the  
> purposes of policy processing. If both sides of the wire use  
> binding.sca then the policies will be determined by the union of  
> the required intents of both sides (policy sets aren't used with  
> binding.sca). Otherwise, the bindings and policies used for the  
> wire will be determined by adding the intents that are required by  
> the binding.sca end of the wire to the other end of the wire and  
> then following the section 4.10 algorithm in the Polcy Framework.
>
> If neither side of the wire uses binding.sca, then the wiring  
> compatibilty algorithm below is used for determining compatibility.  
> Note that there may be many binding instances present at each side  
> of the wire. This algorithm determines the compatibility of a wire  
> by a pairwise choice of a binding instance and the corresponding  
> policySets on each side of the wire.
>
> PROPOSAL:
>
> The following should be added to the Wires section of the Assembly  
> specification:
>
> If either end of a wire does not specify a binding (or explicitly  
> specifies binding.sca) the wire is regarded as valid.  In other  
> words, binding.sca is regarded as being compatible with
> any other type of binding.  Where other types of binding are  
> applied to each end of a wire, compatibility of the two bindings is  
> determined by the specifications for the two bindings
> involved, allied to the intent and policies attached at each end.   
> In general, a wire which has two different binding types at each  
> end (non binding.sca) is likely not to be valid.
>
> If both ends of the wire use binding.sca then the policies will be  
> determined by the union of the required intents of both ends  
> (policy sets aren't used with binding.sca).
> Otherwise, where one end of the wire uses binding.sca, the bindings  
> and policies used for the wire will be determined by adding the  
> intents that are required by the binding.sca end of the wire to the  
> other end of the wire and then following the algorithm defined in  
> the Policy Framework specification section 4.10.
>
> If neither end of the wire uses binding.sca, then the wiring  
> compatibilty algorithm described in section 4.10 of the Policy  
> Framework specification is used for determining compatibility. Note  
> that there may be many binding instances present at each side of  
> the wire. This algorithm determines the compatibility of a wire by  
> a pairwise choice of a binding instance and the corresponding  
> policySets on each side of the wire.
>
>
> Yours,  Mike.
>
> Strategist - Emerging Technologies, SCA & SDO.
> Co Chair OASIS SCA Assembly TC.
> IBM Hursley Park, Mail Point 146, Winchester, SO21 2JN, Great Britain.
> Phone & FAX: +44-1962-818014    Mobile: +44-7802-467431
> Email:  mike_edwards@uk.ibm.com
>
>
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