Aspect-Oriented Modeling of Mutual Exclusion in UML State Machines

Mutual exclusion is a very common requirement in parallel systems. Yet its modeling is a tedious task in UML state machines, one of the most popular languages for behavior modeling. We present HiLA, an aspect-oriented extension of UML state machines, to address this problem. In HiLA, mutual exclusion can be modeled in a highly modular and declarative way. That is, the logic of mutual exclusion is modeled at a dedicated place rather than by model elements scattered all over the state machine, and the modeler only needs to specify which states to mutually exclude rather than how to exclude them.