Title: Message
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
