The Process Element

The Process element is already present in your diagram. The New Project wizards always create a skeletal BPEL file that contains at least a process element. Therefore, the Process element is not part of the Palette. The Process element is assumed to be present, as it is the minimum requirement for a BPEL file.

The following screenshot shows the representation of a process in the Understanding the Travel Reservation Service sample.

Usage

1. Right-click the Process element and choose Add from the pop-up menu to add the following:

   • Variable

   • Correlation Set

   • Event Handlers

   • Fault Handlers

   • WSDL Import

   • Schema Import

2. Specify the name and the target namespace of the Process element in the Properties window, invoked by right-clicking the element and choosing Properties.

Processes

A BPEL process can be synchronous or asynchronous. A synchronous BPEL process blocks the client (the one which is using the process) until the process finishes and returns a result to the client. An asynchronous process does not block the client. Rather it uses a callback to return the result (if any). Usually we use asynchronous processes for longer-lasting processes and synchronous for processes that return a result in a relatively short time. If a BPEL process uses asynchronous web services, the process itself is usually also asynchronous.