RE: [wsrf] Issue WSRF9

yes, that may be true in some cases,
but if the display knew it was maxOccurs>1, the GUI widget might be
different (eg table vs single widget)

sgg

++++++++

Steve Graham

(919)254-0615 (T/L 444)

STSM, On Demand Architecture

Member, IBM Academy of Technology

<Soli Deo Gloria/>

++++++++

"Murray, Bryan P." <>

06/22/2004 02:24 PM
        

        To:
       Steve Graham/Raleigh/IBM@IBMUS

        cc:
       <>

        Subject:
       RE: [wsrf] Issue WSRF9

I think in many cases, a "display
the properties and values" application can display a set of properties
without knowing the cardinality.

 

Bryan

-----Original Message-----

From: Steve Graham [mailto:] 

Sent: Tuesday, June 22, 2004 10:57 AM

To: Murray, Bryan P.

Cc: 

Subject: Re: [wsrf] Issue WSRF9

I agree with Bryan that the "display the properties and values"
is the most "obvious" use case to suggest some sort of runtime
support for additional meta-data on "dynamic" resource properties.
 There may be other use cases, but  I again agree with Bryan's
observation of the need for the application to have a-priori understanding
of the semantics of those resource properties. 

So, in the case of "display the properties and values" the application
would need to know not only the xsd details of the GED (eg type), but also
the cardinality of the resource property use of the GED (minOccurs and
maxOccurs).  The xsd details of the GED can be found (via WS-MetaDataExchange,
for example).  It is the cardinality (and maybe other details) of
the resource property that need to be discovered. 

sgg 

++++++++

Steve Graham

(919)254-0615 (T/L 444)

STSM, On Demand Architecture

Member, IBM Academy of Technology

<Soli Deo Gloria/>

++++++++

"Murray, Bryan P."
<> 

06/21/2004 01:07 PM

        

        To:        <>

        cc:        

        Subject:        [wsrf]
Issue WSRF9

                 I understand the
need to know which properties are currently

present 

                in the property
document given that the property document

supports 

                dynamic properties.
However, I would like to see a use-case

describing 

                the need to retrieve
at runtime the schema for any properties.

                The only reason
I can think of for retrieving properties which

an 

                application does
not already understand is if the application

simply 

                displays properties
to a human or copies the property somewhere.

If 

                the application
understands the namespace of the property it can

                locate the type
from the WSDL/schema for the namespace.

Otherwise, 

                simple properties
(no child XML elements) can be displayed

without 

                understanding their
type by just treating the text node as a

string. 

                The application
can choose to either not display complex

properties or 

                to list attributes
and child elements with their values.

Grandchild 

                elements or attributes
will ultimately make this too complicated

to do 

                at some point.

                Other, more complex,
applications will need to understand not

only the 

                syntax of the properties
they are retrieving, but also the

semantics 

                of those properties
in order to interact with them

appropriately. The 

                syntax can be found
in WSDL/schema files, but the semantics

needs to 

                be understood by
the programmer writing the property retrieval

code. I 

                am confused as
to how an application could interact with a

property it 

                does not understand
beyond simply displaying or copying its

value. If 

                an application
does understand a property that falls into the

xsd:any 

                portion of the
resource property document schema, it does not

need the 

                schema - it already
knows the type of this property.

                If there is no
need beyond displaying or copying the value of an

                unknown property
I suggest that we not provide the ability to

retrieve 

                the schema at runtime.

                Can someone offer
a use-case that shows where my thinking is 

                deficient?

                Bryan