[GRAAP-WG] SLA Template

[Dominic Battre]

Hello everybody,

for the AssessGrid project, we are working on SLA support for our 
resource management system.

At the very moment, I am in the stage of generating an extensive SLA 
template to get a good feeling about the current WSAG specification. (I 
didn't follow the development for some time because I was busy with 
other projects).

I would like to send you my results for comment once they are available, 
but right now I have encountered the first problem already.  Maybe you 
can help me with this:

I would like to add a CreationConstraint that models a boolean flag, 
whether some fault tolerance mechanisms need to be activated.

The respective XML fragment looks like this:

<wsag:Item wsag:Name="Checkpointing">
<wsag:Location>//assessgrid:FTService/assessgrid:Requested</wsag:Location>
<wsag:ItemConstraint>
     <!-- I don't quite know how to put true / false here -->
</wsag:ItemConstraint>
</wsag:Item>

So what do I put there to allow only true and false?

My first idea was to use a xs:restriction like

<xs:restriction base="xs:string">
     <xs:enumeration value="true"/>
     <xs:enumeration value="false"/>
</xs:restriction>

but to my surprise my editor (WTP of Eclipse) tells me that 
xs:restriction is not a valid tag at this place - despite being 
explicitly mentioned in the WSAG specification.  Now, who is right?  The 
syntax checker of the editor or the WSAG spec, or both, meaning that I 
am wrong?

The error message is:
cvc-complex-type.2.4.a: Invalid content was found starting with element
  'xs:restriction'. One of
'{"http://www.w3.org/2001/XMLSchema":simpleType,
   "http://www.w3.org/2001/XMLSchema":minExclusive,
   "http://www.w3.org/2001/XMLSchema":minInclusive,
   "http://www.w3.org/2001/XMLSchema":maxExclusive,
   "http://www.w3.org/2001/XMLSchema":maxInclusive,
   "http://www.w3.org/2001/XMLSchema":totalDigits,
   "http://www.w3.org/2001/XMLSchema":fractionDigits,
   "http://www.w3.org/2001/XMLSchema":length,
   "http://www.w3.org/2001/XMLSchema":minLength,
   "http://www.w3.org/2001/XMLSchema":maxLength,
   "http://www.w3.org/2001/XMLSchema":enumeration,
   "http://www.w3.org/2001/XMLSchema":whiteSpace,
   "http://www.w3.org/2001/XMLSchema":pattern,
   "http://www.w3.org/2001/XMLSchema":group,
   "http://www.w3.org/2001/XMLSchema":all,
   "http://www.w3.org/2001/XMLSchema":choice,
   "http://www.w3.org/2001/XMLSchema":sequence}' is expected.

This matches mostly with the specification except for the xs:restriction.

Coming back to the problem of modeling "Put true or false there", what 
would be the best way?  If I understand the xs:group, xs:all, xs:choice, 
xs:sequence correctly, they all operate on complex types.  Does this 
leave anything but the xs:pattern alternative?  (Note that true/false is 
just a special case for any kind of enumeration.)

Thanks,

Dominic

P.S. In case you have some example files of templates, I would be very 
interested in having a look at them.