W3C home > Mailing lists > Public > public-sws-ig@w3.org > January 2005

Re: The use of the parameterValue property

From: Evren Sirin <evren@cs.umd.edu>
Date: Wed, 12 Jan 2005 19:18:34 -0500
Message-ID: <41E5BE5A.8090705@cs.umd.edu>
To: Daniel Elenius <daele@ida.liu.se>
CC: public-sws-ig@w3.org

Daniel Elenius wrote:

> Evren Sirin wrote:
>
>>
>> Daniel Elenius wrote:
>>
>>>
>>> I brought this up a while ago on this list, and no-one objected to 
>>> deprecating this property, since we have valueData to do the job. 
>>> parameterValue is a leftover from earlier incarnations of OWL-S.
>>
>>
>>
>> I probably missed that message because I would object deprecating 
>> parameterValue. It is possible to use valueData instead of 
>> parameterValue but it is not always straight-forward because 
>> valueData can only be used with Perform construct whereas 
>> parameterValue can directly be attached to a process definition. The 
>> use case is this (and I'm not making up this case we actually have 
>> running examples similar to this one):
>>
>> Suppose there is a WSDL service with two inputs A and B and I want to 
>> define an AtomicProcess grounded in this service. But suppose that 
>> for my application the input B will always be some constant value. It 
>> is very easy to do this using parameterValue, define AtomicProcess P, 
>> two inputs X and Y (mapped to A and B respectively) and attach a 
>> parameterValue to Y to specify the constant value. If we want to do 
>> this using valueData then I have to define AtomicProcess P1 (similar 
>> to P above but no parameterValue), then define CompositeProcess P2 
>> that is a sequence of only one Perform (performing P1) and its input 
>> binding will specify the constant value. As you can see the second 
>> way is harder to do and it is nice to have a compact version of this 
>> functionality.
>>
> You don't need a Sequence if all you have is a single Perform, 

Ah, yes, you're right.

> but I grant that it is a little bit more work to use valueData. I'm 
> not sure it's a good idea to have these multiple ways to do the same 
> thing. If we do, we need to define what happens if there is both a 
> valueData and a parameterValue, and they conflict. 

I agree this is a problem.

> In my view, having parameterValue makes things *more* complicated if 
> you look at the big picture.

Maybe the definition of the parameterValue needs to be changed as the 
"default value" that will be used in case no other value is provided. In 
any case, a clarification about its use needs to be documented.

Evren

>
> Best,
> /Daniel
>
>> Regards,
>> Evren
>>
>>
>>>
>>> /Daniel
>>>
>>> Tatiana Vieira wrote:
>>>
>>>> Hi people,
>>>>  
>>>> Could anyone explain me the use of the parameterValue property? As 
>>>> I understood, the parameterType declares the type of the data the 
>>>> service will produce as output. But how can we use parameterValue? 
>>>> I didn't see any example and as OWL-S doesn't define any model for 
>>>> the result of a process, how/when can we use this property?
>>>>  
>>>> Thank you in advance,
>>>>  
>>>> Tatiana.
>>>>
>>>> ------------------------------------------------------------------------ 
>>>>
>>>> Yahoo! Acesso Grátis 
>>>> <http://br.rd.yahoo.com/mail/taglines/*http://br.acesso.yahoo.com/> 
>>>> - Internet rápida e grátis. Instale o discador do Yahoo! agora. 
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>
>
>
Received on Thursday, 13 January 2005 00:19:31 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Sunday, 16 March 2008 00:10:59 GMT