Most object-oriented (OO) practitioners recognize the value of Design by Contract as a methodology for improving software quality. It is at the heart of the Eiffel language and of the Object ...

The Object Constraint Language (OCL) is a formal language that expresses side effect-free constraints 3,6,7 in UML models. A side effect-free operation is defined as one that will not change the state ...

Four related requests for proposals (RFPs) exist for the UML 2.0: Infrastructure, Object Constraint Language (OCL), XML Metadata Interchange (XMI), and Superstructure.