Operation contracts are formal constraints defined over software operations. These are created during the domain-modeling phase. Typically, an operation contract consists of 4 components: * Operation name: A name for the operation * Cross-References: List of use-cases that refer this operation * Preconditions: State of variables/system before this operation is invoked * Postconditions: State of variables/system after successful completion of the operation Typically, the Postconditions can be of 3 kinds: Name: appropriateName Responsibilities: Perform a function Exceptions: none