Modeling and Formally Checking Workflow Properties Using UML and OCL

In this paper, a new metamodel for workflows is described by using UML. The underlying UML class diagram is formally extended with OCL preand postconditions for operations and OCL invariants for system states. The metamodel allows the developer to specify processes, activities in processes and temporal relations between them. Known workflow patterns are formally captured in the metamodel and sophisticated temporal relations between activities can be expressed easily. Development of workflow models is explained as well as process instantiation and process execution on the basis of a tool realizing parts of the UML action semantics. Prototypical process execution and animation allows the designer to discover properties of the designed processes and activities in early phases of the development without the need for building a full implementation.