Uno/Spec/Purpose Environment
Type: specification State: draft Claim: recommended
Feature
Environment type naming is extended by introducing a so called "purpose" part, actually changing the environment type name to become an Environment Descriptor, defining the environment Object Binary Interface (OBI) and the environment purpose.
Environments are described as
"<OBI>[:<purpose>]*"
meaning that purposes can be chained. This allows to have different environments of the same OBI types to be globally visible, differing in their purpose. For example:
-
"uno:affine" -
"uno:debug" -
"uno:log:affine" -
"gcc3:debug" -
"gcc3"
When requesting the above examples, every environment is globally visible, while partly representing the same type or purpose, every combination is unique. Semantically, the former string describing an environments OBI now becomes an Environment Descriptor.
Rationale
Currently every UNO environment is either anonymous or globally visible. All globally visible environments are uniquely identified by their OBI (type) name. That means, that every bridge specific environment (such as "gcc3") can only be visible once globally. To be able to use more than one OBI type specific environment in a global way, support for a differentiator is needed. Together with Cascaded Mappings purpose environments are a powerful instrument for isolating and controlling sets of objects.
API
String getTypeName(String envDcp); String getPurpose (String envDcp);
Compatibility
The character ':' gets a special meaning in all environment OBI type names. All Runtime functions dealing with environment OBI names, e.g.
getEnvironment getRegisteredEnvironments createEnvironment dumpEnvironmentByName
are to support Environment Descriptors. All parameter names are to reflect this semantics.
In case of not providing purposes in an environment descriptor, the env. descriptor degenerates to just an environment OBI name. This means, that the change is compatible with all former usages and bridges, in case it does not get utilized. To utilize this feature, bridges should use the appropriate accessor methods to get the OBI or purpose part from an environment descriptor.
Note: Purpose environments _must_ not be used with not purpose environment aware Language Bindings.
