SOA for Legacy IT Systems

The software architecture is illustrated in the following figure. The interface is exposed using XML to transfer across environment divides. The service mediator acts as the interface and exposes the service to other applications. It also controls the transaction, retrieves the XML message, parses the XML, authenticates the service request, sets up the context container, resolves and instantiates the requested service and returns the XML message.

The service mediator calls the service controller, which then calls the business domain components making up the application in turn. Components are completely decoupled: they communicate only via the context container. Each component reads its input data from the context container and writes its output data into the context container. Thus each component can be tested separately as long as the data required for a component is inserted into the context container.

The proposed software architecture allows the composition of new service components and existing software components. In fact, our solution enables us to establish a complete Service Oriented Architecture (SOA) in any existing IT systems with their existing applications.