Extracting service candidates from procedural programs based on process dependency analysis

To support legacy migration to service-oriented architecture (SOA), this paper presents a method that derives candidates of SOA services from procedural programs. In SOA, every service is supposed to be a process (procedure) with (1) open interface, (2) self-containedness, (3) coarse granularity for business. We identify such services from the source code and its data flow diagram (DFD), by analyzing data and control dependency among processes. Specifically, we first obtain the DFD with reverse-engineering techniques. For each layer of the DFD we classify every data flow into three categories. Using the data category and control among procedures, we characterize four types of dependency. We finally apply six rules that aggregate mutually dependent procedures and extract them as a service. A case study with a liquor shop inventory control system extracts service candidates with various granularity.