Constraints
In the context of UML, Object Constraint Language (OCL) is often used to define preconditions and postconditions for operations (methods) of a class. Preconditions and postconditions specify the requirements that must be satisfied before and after an operation is invoked. They help ensure the operation’s behavior is well-defined and adheres to certain constraints. Here’s an explanation of preconditions and postconditions in OCL:
- Preconditions:
- Preconditions define conditions that must be true before an operation can be executed. They describe the state of the system or object that must be in place for the operation to proceed.
- Preconditions are typically specified using OCL expressions and are associated with a specific operation in a UML class diagram. These expressions are evaluated before the operation is executed.
- If a precondition is not satisfied when the operation is invoked, the system should prevent the operation from executing and report an...