Operation

In UML, an Operation is a Behavioral Feature of a Classifier that specifies the name, type, Parameters, and Constraints for invoking associated Behavior. The Operation specifies an invocation contract, while a Method or another Behavior realizes it.

SimpleModeling treats an Operation as a contract through which an Object provides a Responsibility. For a state-changing Operation, it makes Preconditions, preserved Invariants, Postconditions, Outcomes, and emitted Events explicit.

OperationDefinition in simplemodeling-lib defines Parameter semantics and the value-resolution boundary for a protocol Operation. ParameterDefinition declares name, kind, and Value Domain, while resolveParameter performs raw-value extraction, Multiplicity validation, normalization, and Constraint validation exactly once. This is a realization at the protocol boundary, not a representation of all UML Operation semantics.