RE: [wsrf] Proposed resolution - re: InitialValues for properties in WS-RMD

[Daniel Jemiolo <danjemiolo@us.ibm.com>]

Bryan,

You are correct that the initial values
have no relevance to the client. However, I think that the use cases of
this spec are not limited to introspection by clients. RMD can also be
used by resource implementations to initialize WS-RP documents and enforce
metadata for some or all properties (depending on how/where the properties
are stored). It's a case of wanting to reuse an artifact we already have
rather than inventing something that's implementation-specific.

For example, if you had an IDE that
allowed you to design and generate WS-* interfaces and the many artifacts
that are required to deploy them, you could use the RMD document (and other
artifacts) to automate parts of the WS-* configuration at runtime. This
type of automation allows programmers to focus on their custom resource/manageability
logic and less on enforcement of basic WS-concepts and plumbing.

Also, Kirk is correct - the term "default"
values is semantically inaccurate. I will stick to "initial values".

Dan

"Murray, Bryan P." <bryan.murray@hp.com>

04/06/2006 03:20 PM

To	Daniel Jemiolo/Durham/IBM@IBMUS, <wsrf@lists.oasis-open.org>
cc
Subject	RE: [wsrf] Proposed resolution - re: InitialValues for properties in WS-RMD

Dan,
 
I will add this issue as you wrote
it to the issues list.
 
 
My comments on this issue:
 
Maybe I am getting confused by
the terminology, but to me something called "initial" values
in a metadata document would not be modified, added or removed over time.
The initial values would be used to initialize properties when a resource
was created. After creation, the initial values metadata has no further
use. The current value of the resource properties are available from the
resource, but the initialValue metadata has no meaning once the resource
has been created. With this understanding of the semantics, this metadata
has minimal value to a client interacting with a resource having these
initial values, as an instant after creation the resource is running and
having its values changed to reflect the state of the resource.
 
What am I missing? I don't understand
how the initial values is useful to a client. The metadata is only an advertisement
about the service, but why advertise something that has minimal value?
 
Bryan

---

From: Daniel Jemiolo [mailto:danjemiolo@us.ibm.com]
Sent: Thursday, April 06, 2006 11:40 AM
To: wsrf@lists.oasis-open.org
Subject: [wsrf] Proposed resolution - re: InitialValues for properties
in WS-RMD 


On the TC call on 4/3/06, I proposed that we (re-)add the concept of initial
values to the WS-RMD spec. This issue does not have a number yet. Below
is a description of the issue and the proposed resolution.

When programming against the RMD spec, it is often necessary to seed a
property with a set of initial values that are known at design time. A
better term might be "default" values. The difference between
these initial values and the concept of static values already in the spec
is that initial values should be mutable, while static values are not.

The definition of initial values in an RMD document would be just like
that of static values. For example, a property named MyProperty of type
integer might have the following definition: 


<wsrmd:Property path="myns:MyProperty" ... >
   <wsrmd:InitialValues> 
      <myns:MyProperty>123</myns:MyProperty>
      <myns:MyProperty>456</myns:MyProperty>
   </wsrmd:InitialValues> 
</wsrmd:Property> 


If the property is mutable, these initial values may be deleted or updated
over the resource's lifetime. Again, this is different from static values
because even on mutable properties, static instances are never deleted
or updated. 

The proposed resolution is to add the initial values concept to RMD by
copying the section on static values (8.4), doing a search-and-replace
(StaticValues -> InitialValues), and modifying the two introductory
sentences to describe the role of initial values. The schema and infoset
figures (in section 8 and appendices) will also need to be updated to reflect
this option. 





Dan Jemiolo
IBM Corporation
Research Triangle Park, NC


+++ I'm an engineer. I make slides that people can't read. Sometimes I
eat donuts. +++