Orchestrations subscribe and publish messages to the MessageBox. They can do this in a number of different ways dependent on what messaging pattern the developer wants to use. Orchestrations can be bound directly to the MessageBox, bound to Receive and Send Ports or configured to route messages between Orchestration instances. The only time the MessageBox is not involved is when you use the Call Orchestration shape to initiate execution of another Orchestration, as explained earlier in this chapter. For the next few sections we are going to examine Orchestration Ports and Subscription patterns.
Ports in Orchestrations describe how the Orchestration will communicate with the MessageBox and the direction of that communication, inbound or outbound. Ports are based on Port Types. The Port Type describes the Communication Pattern (one-way or request-response) and MessageType communicated. A Port Type can have a one-to-many relationship...