DILT: A Hybrid Model for Dynamic Composition and Execution of Heterogeneous Web Services

Business applications in domains such as e-Governance, require collaboration among both Governmental and non Governmental departments, which raises the need for composing SOAP-based as well as RESTful services. Existing works address this objective using static composition alone. However, it would be beneficial if users can specify the requirements during run-time, based on the outcome of the previous services executed. In general, business applications follow a predefined order and consequently the composition process can follow a template of business activities. Existing works on dynamic web service composition either separate the composition and execution phases distinctly or perform them in an interleaved fashion. The former approach cannot adapt to changes in run-time whereas the latter can select services based on the outcome of previous service executions. However, the interleaved approach does not support business activities that have a specific ordering among them. Hence, a novel hybrid model - Dynamic InterLeaved Template (DILT) - that enables interleaved composition and execution of web services based on predefined workflow templates has been proposed in this paper. This hybrid model lends itself naturally for composing both SOAP-based and RESTful services.