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Subject: Re: [sca-assembly] [Issue 95] "wiredByImpl" is an invalid attributefor a Composite Reference


Dave,

I'm not sure I understand why you say:
"... promotion as a concept is incompatible
with wiredByImpl which clearly wants the wiring configuration to be
  managed by the component implementation."

I suspect I'm probably not getting it. Here is how I see it:
Promotion is essentially an act of setting the CT associated with 
composite. A wiredByImpl reference can never be wired by a SCDL file 
(regardless of where the origins of that reference are). All one can do 
wrt wiredByImpl ref is change policy/intent/bindings -- this is true 
regardless of whether is it present in a atomic component or not.

I do think that we need to say that a promoted wiredByImpl must be 
explicitly mark as such (I suppose we could default it) -- in effect the 
CT associated with the composite must show wiredByImpl='true'.

-Anish
--

David Booz wrote:
> Another way to go here is to consider that the act of promotion is a 
> conscious act of creating public visibility for the purposes of 
> configuration. In this sense, promotion as a concept is incompatible 
> with wiredByImpl which clearly wants the wiring configuration to be 
> managed by the component implementation. Therefore, we could decide that 
> wiredByImpl + promotion is an error. I don't recall, did we discuss this 
> on the call? Perhaps we did and too much of Mom's cooking has dulled my 
> memory.
> 
> Dave Booz
> STSM, BPM and SCA Architecture
> Co-Chair OASIS SCA-Policy TC and SCA-J TC
> "Distributed objects first, then world hunger"
> Poughkeepsie, NY (845)-435-6093 or 8-295-6093
> e-mail:booz@us.ibm.com
> 
> Inactive hide details for Simon Nash ---11/30/2008 07:01:35 PM---Anish, 
> I agree with your comments about the meaning of wiredBySimon Nash 
> ---11/30/2008 07:01:35 PM---Anish, I agree with your comments about the 
> meaning of wiredByImpl on a
> 
> 
> From:	
> Simon Nash <oasis@cjnash.com>
> 
> To:	
> OASIS Assembly <sca-assembly@lists.oasis-open.org>
> 
> Date:	
> 11/30/2008 07:01 PM
> 
> Subject:	
> Re: [sca-assembly] [Issue 95] "wiredByImpl" is an invalid attribute for 
> a Composite Reference
> 
> ------------------------------------------------------------------------
> 
> 
> 
> Anish,
> I agree with your comments about the meaning of wiredByImpl on a
> composite reference.  This is the point I was trying to make
> (albeit not very successfully) on the call.
> 
> Regarding 0..0, I don't think this is the same as wiredByImpl.
> I think a wiredByImpl reference could be 0..1, 1..1, 0..n or 1..n.
> 
> If it is 1..n or 0..n, it's represented by an array in a Java
> component implementation; otherwise it's represented by a scalar.
> 
> If it is 0..1 or 0..n, the implementation is allowed to wire it but
> is not obliged to do so; otherwise, the implementation must wire it.
> 
>   Simon
> 
> Anish Karmarkar wrote:
>  > Mike,
>  >
>  > Apologies for misunderstanding your proposal on the call today.
>  > Unfortunately, line numbers on a 2007 .doc file don't mean a whole lot
>  > to me.
>  >
>  > IIUIC, what you are proposing is to get rid of the attribute wiredByImpl
>  > on a composite reference, while retaining the ability to promote a
>  > component reference that has wiredByImpl='true'.
>  >
>  > If this is correct, I think this is problematic. Without the
>  > wiredByImpl='true', the componentType associated with the composite will
>  > not contain information about the fact that the reference cannot be
>  > wired. Higher-level composites won't know the cardinality associated
>  > with the reference (which is 0..0) and therefore will be free to wire
>  > it. Unless, the spec says that wiredByImpl='true' automatically becomes
>  > part of the CT associated with the composite by the virtue of the fact
>  > that the underlying component reference has wiredByImpl='true'. We allow
>  > narrowing of constraints when promoting. A 0..0 cannot be narrowed any
>  > further, so wireByImpl='true' is indeed ripe for defaulting in such 
> cases.
>  >
>  > But as it stands I don't think there is any inconsistency in the spec
>  > (other than the fact that it does not say that you cannot change the
>  > value of wiredByImpl when promoting).
>  >
>  > Currently, wiredByImpl says:
>  > "wiredByImpl : boolean (0..1) - a boolean value, "false" by default,
>  > which indicates that the implementation wires this reference
>  > dynamically.  If set to "true" it indicates that the target of the
>  > reference is set at runtime by the implementation code (eg by the code
>  > obtaining an endpoint reference by some means and setting this as the
>  > target of the reference through the use of programming interfaces
>  > defined by the relevant Client and Implementation specification).  If
>  > "true" is set, then the reference should not be wired statically within
>  > a composite, but left unwired."
>  >
>  > Which seems right to me. There is implementation code associated with a
>  > composite reference: it is the code associated with the corresponding
>  > promoted component reference (however levels deep).
>  >
>  > OTOH, the existence of wiredByImpl when we already have the multiplicity
>  > attribute (on both component reference as well as composite reference)
>  > always seemed a little strange to me. wiredByImpl is really saying
>  > multiplicity of 0..0, why not then just say exactly that. I know this
>  > was discussed during the OSOA days, but I don't recall why addition of a
>  > new attribute was chosen over 0..0.
>  >
>  > I'll be bold and make a proposal to remove wiredByImpl altogether and
>  > use 0..0 on the multiplicity attribute instead (with the usual narrowing
>  > rules for promotion).
>  >
>  > I'm hoping that, if there was a good argument for choosing wiredByImpl
>  > over 0..0 in OSOA, someone will bring it up here.
>  >
>  > Comments?
>  >
>  > -Anish
>  > --
>  >
>  > Mike Edwards wrote:
>  >>
>  >> Raiser:                Mike Edwards
>  >>
>  >> Target:                Assembly spec: 
> sca-assembly-1.1-spec-cd01-rev3.doc
>  >>
>  >> Description:
>  >>
>  >> The current spec has the attribute @wiredByImpl as an attribute of a
>  >> Composite reference element.
>  >> This cannot be valid, since there @wiredByImpl=true implies that the
>  >> composite itself will act to wire
>  >> the reference at runtime.  However, this can never happen since there
>  >> is no active code in the
>  >> composite which could do this.
>  >>
>  >> It is valid for a reference on a component within the composite to
>  >> have @wiredByImpl on one of its
>  >> references, but this applies to wiring of the component reference -
>  >> and NOT to wiring of any
>  >> promotion of that reference.
>  >>
>  >> Proposal:
>  >>
>  >> Remove @wiredByImpl from <reference/> within a <composite/>.
>  >>
>  >> Specifically:
>  >>
>  >> Line 1337 - remove  wiredByImpl="xs:boolean"?
>  >>
>  >> Lines 1399 - 1405 - remove
>  >>
>  >> Lines 3825 - 3826 - remove
>  >>
>  >> Lines 3971 - 4006 - replace with:
>  >>
>  >>     <complexType name="ComponentReference">
>  >>
>  >>             <complexContent>
>  >>
>  >>                             <sequence>
>  >>
>  >>                                     <element ref="sca:interface"
>  >> minOccurs="0" maxOccurs="1" />
>  >>
>  >>                                     <element name="operation"
>  >> type="sca:Operation" minOccurs="0"
>  >>
>  >>                                             maxOccurs="unbounded" />
>  >>
>  >>                                     <element ref="sca:binding" />
>  >>
>  >>                                     <element ref="sca:callback"
>  >> minOccurs="0" maxOccurs="1" />
>  >>
>  >>                                     <any namespace="##other"
>  >> processContents="lax" minOccurs="0"
>  >>
>  >>                                             maxOccurs="unbounded" />
>  >>
>  >>                             </sequence>
>  >>
>  >>                             <attribute name="name" type="NCName"
>  >> use="required" />
>  >>
>  >>                   <attribute name="autowire" type="boolean"
>  >> use="optional" />
>  >>
>  >>                             <attribute name="wiredByImpl"
>  >> type="boolean" use="optional"
>  >>
>  >>                         default="false"/>
>  >>
>  >>                             <attribute name="target"
>  >> type="sca:listOfAnyURIs" use="optional"/>
>  >>
>  >>                             <attribute name="multiplicity"
>  >> type="sca:Multiplicity"
>  >>
>  >>                                     use="optional" default="1..1" />
>  >>
>  >>                             <attribute name="requires"
>  >> type="sca:listOfQNames" use="optional"/>
>  >>
>  >>                         <attribute name="policySets"
>  >> type="sca:listOfQNames"
>  >>
>  >>                                 use="optional"/>
>  >>
>  >>                             <anyAttribute namespace="##other"
>  >> processContents="lax" />
>  >>
>  >>             </complexContent>
>  >>
>  >>     </complexType>
>  >>
>  >>
>  >> 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
>  >>
>  >>
>  >> ------------------------------------------------------------------------
>  >>
>  >> /
>  >> /
>  >>
>  >> /Unless stated otherwise above:
>  >> IBM United Kingdom Limited - Registered in England and Wales with
>  >> number 741598.
>  >> Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6
>  >> 3AU/
>  >>
>  >>
>  >>
>  >>
>  >>
>  >>
>  >
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