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Difference between revisions of "ContextId"
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== Definition == | == Definition == | ||
* A [[ContextId]] is a kind of [[Attribute]] that uniquely identifies a [[Context]]. | * A [[ContextId]] is a kind of [[Attribute]] that uniquely identifies a [[Context]]. | ||
− | * The value of a [[ContextId]] | + | * The value of a [[ContextId]] is a [[Context]] |
* Two different [[ContextId]]s may refer to the same [[Context]]. | * Two different [[ContextId]]s may refer to the same [[Context]]. | ||
* If the value of a [[ContextId]] is resolvable, its value should dereference the information necessary to discover how to access a [[Context]]. See [[Context Discovery]]. | * If the value of a [[ContextId]] is resolvable, its value should dereference the information necessary to discover how to access a [[Context]]. See [[Context Discovery]]. |
Revision as of 12:53, 22 April 2008
{{#eclipseproject:technology.higgins}}
Version
This page describes the concept of a ContextId as used in Higgins Global Graph 1.1.
Definition
- A ContextId is a kind of Attribute that uniquely identifies a Context.
- The value of a ContextId is a Context
- Two different ContextIds may refer to the same Context.
- If the value of a ContextId is resolvable, its value should dereference the information necessary to discover how to access a Context. See Context Discovery.
Details
- It is not required for a ContextIds to resolve to a Context instance in which case this is referred to as an abstract ContextId. However, most Contexts are not abstract, and can be resolved a network (or local) data access service to discover the information necessary to access the Context.
ContextIds and IdAS
- The Identity Attribute Service (IdAS) can be used as a service to access a Context given a ContextId.
- If two ContextId's values are equal, they refer to the same underlying Context, although not necessarily the same Context "container" instance returned by IdAS. This means that, as a requester of information, different clients of IdAS may see different subsets of the Context based on the authorization passed in during authentication.
- A given ContextId may be used against multiple Context Providers to produce the same Context (although, as mentioned, different Context instances).