BizTalk™ Unleashed

Message Flow Behavior

In this section, we review how messages flow into or out of a schedule through the ports. The XLANG Scheduler Engine, which hosts the schedule instance, manages the flow of messages in the running schedule. When an Action is performed, the running schedule intercepts messages that flow into or out of it, via a port. If the port is connected to a COM component, the schedule instance also holds (the proxy to) the component's interface needed for passing messages to it. Messages entering the schedule are captured as part of the schedule state; they are optionally parsed based on a schema, and the fields of the captured messages are available to populate outgoing messages or for use in Rule expressions within the schedule.