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Re: Something else to consider

From: Umit Yalcinalp <umit.yalcinalp@oracle.com>
Date: Mon, 14 Jul 2003 14:22:46 -0700
Message-ID: <3F131F26.4060603@oracle.com>
To: "VAMBENEPE,WILLIAM (HP-Cupertino,ex1)" <vbp@hp.com>
CC: "'Sanjiva Weerawarana'" <sanjiva@watson.ibm.com>, Jim Webber <jim.webber@arjuna.com>, "'Savas Parastatidis'" <Savas.Parastatidis@newcastle.ac.uk>, public-ws-desc-state@w3.org


VAMBENEPE,WILLIAM (HP-Cupertino,ex1) wrote:

>I find this elegant, but my main question is how this meets the requirements
>we have listed. I can see many requirements that don't appear to be met by
>this, such as ability to query over multiple attributes and ability to
>attach metadata to attributes. Or am I missing something in this proposal?
>Do the get and set operations allow more advanced syntax to meet these
>requirements?
>
>Regards,
>
>William
>

It seems to me that we are defining a set of attributes and a well 
defined way to query/modify them without assuming the existence of 
operations in WSDL, right? As a result, our goal is then to specify 
well-defined messages that would instead express the same information as 
if the operation(s) were to exist in WSDL. Not specifying the message 
content would be unacceptable as it is an interoperability problem.

I had the same question as William with respect to this syntax. If I 
understood correctly, this approach favors defining get/setXX messages 
per attribute basis. Unless there is a well defined message where 
multiple attribute names can be referenced, it is not clear to me how a 
general query can be expressed. This favors using an operation unless we 
were to extend the attribute definitions to encapsulate both attributes 
and query messages that can be expressed, something along the lines of

<attributes>
    <attribute>...</attribute>
    <attribute>...</attribute>
     <attribute-query> to be defined </attribute-query>
</attribute>

I am also not clear about Savas' proposal and I have some questions:

-- How is the complexType in the body of get/set element used? For 
example, I would have expected the get message not to specify anything 
as it is obvious from the structure that there is an attribute that it 
is related to. Similarly, what are the body/element defns?
I would not expect anything in the body of a message that corresponds to 
this definition as it is clear from the defn which attribute that the 
get message is for.

-- The same question goes for the setter. Can a set message contain 
information other than the value of the attribute? Again the 
body/element defns appear to allow more than the traditional use of a 
setter would allow. I would like to understand better.

-- If the WSDL contains get/set operations, how would be distinguish 
them based on the message content alone?

Thanks.

--umit


>
>  
>
>>-----Original Message-----
>>From: Sanjiva Weerawarana [mailto:sanjiva@watson.ibm.com] 
>>Sent: Monday, July 14, 2003 7:02 AM
>>To: Jim Webber; 'Savas Parastatidis'; public-ws-desc-state@w3.org
>>Subject: Re: Something else to consider
>>
>>
>>
>>I think I like this too! Basically it says an attribute is a
>>different set of messages that are grouped together; one to
>><get> the attribute and one to (optionally) <set> the attribute.
>>An <operation> OTOH is a set of messages that are sent and 
>>(optionally)
>>received.
>>
>>Let's see what Steve thinks .. he's back from vacation but
>>is prolly buried in email.
>>
>>Sanjiva.
>>
>>----- Original Message -----
>>From: "Jim Webber" <jim.webber@arjuna.com>
>>To: "'Savas Parastatidis'" <Savas.Parastatidis@newcastle.ac.uk>;
>><public-ws-desc-state@w3.org>
>>Sent: Monday, July 14, 2003 3:13 PM
>>Subject: RE: Something else to consider
>>
>>
>>    
>>
>>>Savas:
>>>
>>>This seems a nice solution. But what about headers? In our 
>>>      
>>>
>>(offline) talk
>>we
>>    
>>
>>>covered some of these issues, but could you follow through 
>>>      
>>>
>>in this group
>>    
>>
>>>too?
>>>
>>>Jim
>>>
>>>      
>>>
>>>>-----Original Message-----
>>>>From: public-ws-desc-state-request@w3.org
>>>>[mailto:public-ws-desc-state-request@w3.org] On Behalf Of
>>>>Savas Parastatidis
>>>>Sent: 13 July 2003 23:36
>>>>To: public-ws-desc-state@w3.org
>>>>Subject: Something else to consider
>>>>
>>>>
>>>>
>>>>All,
>>>>
>>>>Drawing from Sanjiva's very good suggestion in the WSDL
>>>>mailing list for the removal of <message>, please allow me to
>>>>suggest another syntax for attributes for all of us to consider:
>>>>
>>>><attribute name="ncname">
>>>>    <get [(body="qname") | (element="qname")]>
>>>>        [<xsd:complexType> ... </xsd:complexType>]
>>>>    </get>
>>>>    <set [(body="qname") | (element="qname")]
>>>>        [<xsd:complexType> ... </xsd:complexType>]
>>>>    </set>
>>>></attribute >
>>>>
>>>>It's very similar to Sanjiva's syntax for the operation.
>>>>Absence of a get or a set will make the attribute write-only
>>>>or read-only respectively.
>>>>
>>>>It is still the case that binding will be required.
>>>>
>>>>
>>>>Going back to David's comments on the requirement for having
>>>>"static" attributes in a WSDL document... I would argue that
>>>>the only reason one would want to put a static value in an
>>>>interface document is because they want to make available
>>>>metadata information. I believe that the current draft of
>>>>WSDL already supports this through the <feature> and
>>>><property> elements, if I haven't misunderstood the intention
>>>>for their introduction.
>>>>
>>>>Regards,
>>>>.savas.
>>>>
>>>>
>>>>
>>>>        
>>>>
>
>  
>

-- 
Umit Yalcinalp                                  
Consulting Member of Technical Staff
ORACLE
Phone: +1 650 607 6154                          
Email: umit.yalcinalp@oracle.com
Received on Monday, 14 July 2003 17:23:17 UTC

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