OSA reference

Attribute operations

These can be performed on one or more attributes specified when the operation is called. Those procedures that are invoked per attribute will be called once for each attribute listed in the client's request for each object in the request.

An operation of this type can be applied individually on each of the attributes specified on the command line, or on all the attributes at once. This synchronization of this application is left up to the OSA writer to decide. If the writer decides to have each attribute applied individually (on a per attribute basis), then each attribute application should be attempted regardless of the success or failure of any attribute's attempt. If the writer decides to have all the given attributes evaluated at once (on a per object basis), then the writer should write code that will either always apply all the attributes successfully, or none at all. The operations that modify or access an object's attributes are as follows:

Return a value or set of values for each specified attribute. If no attributes are specified, the values of all attributes of the current object are returned.

Replace the current value of the specified attribute with a new specified value.

Replace the current value(s) of the specified attribute(s) with a default value. If no attributes are specified, replace attribute values for the current object instance with defaults.

Add the specified value(s) to the current set of values associated with the specified attribute of the current object instance.

Remove the specified value(s) from the current set of values associated with of the specified attribute of the current object instance.

Limit the affected object instances as defined. This is the only operation of all the attribute accessing functions that can only be written on a per attribute synchronization.
In the passed data structure, only these parameters are important to per-attribute operations:

class name
The class to which the specified object instance belongs. This accommodates sharing procedures between classes.

object name
The object instance being worked on. The OSA should check the existence or validity of the object instance.

operation name
The operation being worked on. This accommodates procedures being shared by operations by providing a way for the procedure to identify which operation is calling it.

attribute token
The token for the attribute being worked on. Simple operations can act on each attribute in one procedure, but more complex operations can simply identify which attribute is being worked on and forward the relevant information to an appropriate subroutine.

attribute list
The attributes (and corresponding values) specified when the operation was called.

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