Constraint-based processes require a set of rules that limit their behavior
to certain boundaries. In these processes, the control flow is defined
implicitly as a set of constraints or rules, and all possibilities that do
not violate any of the given constraints are allowed to be executed. The
present paper proposes a new approach to deal with constraint-based
processes. The proposed approach is based on Supervisory Control Theory, a
formal foundation for building controllers for discrete-event systems. The
controller proposed in this paper monitors and restricts execution sequences
of activities such that constraints are always obeyed. We demonstrate that
our approach may be used as a declarative language for constraint-based
processes. In order to provide support for users of such processes and to
facilitate the using of our control approach, we offer a set of constraints
modeled by automata. This set encompasses the constraints frequently needed
in workflow system.