A Chemical Based Middleware for Workflow Instantiation and Execution

Service-Oriented Architecture (SOA) is widely adopted today for building loosely coupled distributed applications. With this approach, new applications can be built by creating a business process that defines a concrete workflow composed of different partner services available via the network. In this scenario, the bindings between the business process and partner services are predefined by statically referencing the corresponding endpoints. This paper proposes a middleware architecture for dynamical workflow instantiation and execution. Using this middleware, partner services are selected and bound in the run-time and the aggregated QoS values are ensured to satisfy the requester's end-to-end QoS requirement. The selection is based on both non-functional requirement (such as price and response time) of the global composition, and Quality of Service (QoS) performance of each candidate service. The implementation is based on chemical computing, a parallel and autonomic computing paradigm that allows to model workflow instantiation and execution as an evolving and adaptable process.