Some clarifications on Resource Shapes

["Jim Amsden" <jamsden@us.ibm.com>]

Today on the TC call, there were some discussions
about lack of clarity in the Resource Shapes specification. I make a few
changes I hope helps clear up how shapes are associated with resources,
and which associated shapes apply to the resources.

I update the Terminology section with:

applicability
Shapes associated with a resource apply to that resource
if the shape's oslc:describesproperty matches the type of the assocated resource, or the shape has no
oslc:describes property
in which case it applies to all associated resources. For all shapes that
"apply to" or describes an associated resource, that resource
should satisfy the constraints defined by those shapes. See Associating
and Applying Shapes for the definition of how
shapes are associated with resources, what associated shapes apply to a
resource, and what it means if multiple shapes apply to a single resource.

association
This specification defines three contexts in which a shape
may become associated with a described resource. The described resource
itself may link to a shape using the property oslc:instanceShape,
the described resource may be the entity request to or response from a
REST service whose service description links to a shape using the property
oslc:resourceShape,
or the the resource may be the object value of a Property whose oslc:valueShapelinks to the constraining shape. More than one shape may become associated
with a described resource in a given context. The shapes associated with
a resource are the set of shapes to be checked for applicability. Not all
the associated shapes are necessarily applicable. Refer to the definition
of applicability above. 

The previous definitions appeared incomplete.

I changed the first paragraph in section
6.2 Associated and Applying Shapes to:

In general, the relation between shapes and resources
is many-to-many. Given a resource R there MAY be zero or more shapes
S associated with it. This specification defines three ways to associate
shapes with a resource, namely using oslc:instanceShape,
oslc:resourceShape,
and oslc:valueShape.
Other specifications MAY define additional mechanisms.

1. Resource oslc:instanceShapeResourceShape - directly associates a constraining shape with a resource.
2. Service oslc:resourceShapeResourceShape - associates a constraining shape with the entity request or response response resource of a service (e.g., a creation or query service).
3. Property oslc:valueShapeResourceShape - associates a constraining shape with the resource that is the object value of a property of a some resource.

Not
all shapes associated with a resource are necessarily applicable to it.
Let S be associated with R. S is said to apply to R in the following
two cases:

This more complete and consistent with the updated definitions of applicability and association.

Anyone see any problems with these updates?

Jim Amsden, Senior Technical Staff Member
OSLC and Linked Lifecycle Data
919-525-6575