Design of a Dynamic Composition Handler for ESB-based Services

The capability to compose services dynamically is a unique feature of Service-Oriented Computing (SOC), where services are published, discovered, and composed at runtime to deliver the expected service functionality to service clients. With dynamic composition, published services are searched and the most appropriate services are selected and reused at runtime. Also, newly published services can be reused without changing the client programs, so it yields an opportunity for dynamic adaptation. Despite the benefits, current programming languages, SOC platforms, business process modeling languages, and tools have a limitation on supporting the full dynamic composition. Rather, they require either manual composition or static binding of available services. In this paper, we present a design of a Dynamic Composition Handler on Enterprise Service Bus (ESB). We analyze different types of service compositions to clarity what dynamic composition really holds in SOC. Then, we present a design of Dynamic Composition Handler which consists of four elements; Invocation Listener, Service Router, Service Discoverer, and Interface Adapter. Using the framework, services can be discovered, selected, composed, and adapted at runtime. Since practical dynamic composition method depends on certain standard middleware platforms, we adopt ESB for our framework. We believe that our framework enables practical dynamic composition and realizes the whole benefit of it.