SERSCIS

The figure below shows the architecture of the service composition component.

The software infrastructure consists of an Enterprise Service Bus (Apache ServiceMix), a BPEL Workflow Execution Engine (a customised version of Apache ODE), a Resource Registry (based on the WSO2 Governance Registry and accessed via a registry adapter) and a set of custom built core components. These are:

• The Workflow Composer selects the concrete services provided by the Resource/Service Registry at runtime. In particular, it implements a ranking mechanism to support this local selection step.
• It is the Router’s responsibility to forward messages to the appropriate endpoints. For outbound messages, which address an endpoint just by semantic information, the router handles the service binding and ensures the availability of suitable, dynamically created endpoints. For inbound messages it can be configured to route them via a policy enforcement point. It can also apply fault handling strategies in the case of communication faults.
• The Notification Agent collects notifications and events from various components and produces higher level notifications according to a set of rules. The higher level notifications are then evaluated by decision support and system governance.
• The Administration component provides interfaces for administering the orchestration components and the set of deployed workflow templates.