Enhancing OCL for Specifying Pre- and Postconditions

This paper proposes a number of enhancements to UML's Object Constraint Language to improve its usability for specifying operations by pre- and postconditions. In particular, we propose notational shortcuts and semantic modifications to OCL so that it can be more effectively used by developers. Also, the paper discusses an approach for specifying, in OCL, events and exceptions which are output and raised by an operation.