Specification and Implementation of Workflow Control Patterns in Reo

Abstract

Abstract <br /><br /> Coordination models and languages are relatively new methods in modeling component-based software systems. These models and languages separate the communication aspect of systems from their computation aspect, and hence enable the modeling of concurrent, distributed, and heterogeneous systems. In this thesis, our goal is to show that Reo, a channel-based exogenous coordination language, is powerful enough to be used in the area of workflow management. In order to achieve this goal, we consider a set of workflow control patterns. We implement each of these patterns in terms of a Reo circuit and show that these Reo circuits capture the behavior of the corresponding workflow control patterns. We believe that the patterns we choose in this thesis are enough to show the strength of Reo as a workflow language. <br /><br /> We explain our approach in four steps. In the first step, we specify the general definition of workflow control patterns in terms of some Point Interval Temporal Logic formulas. In the second step, we convert each PITL formula to a constraint automaton. In the third step, we implement each workflow control pattern by a Reo circuit; each Reo circuit consists of a set of <em>components</em> and a set of <em>connectors</em> that connect and coordinate those components and provide its behavior as a relation on <em>timed data streams</em>; a timed data stream is a twin pair of a data stream and a time stream. In the forth step, we compositionally derive the constraint automata of that Reo circuit and finally, in the fifth step, we show the equivalence of the two constraint automata.