Next Generation Application Integration: From Simple Information to Web Services

BPEL4WS Process Syntax

At its essence, the BPEL4WS process itself is a flowchart-like expression of an algorithm.^[3] Each step is known as an activity, and there are a bunch of primitive activities (subactivities if you will) that actually

^[3] Weerawarana, Sanjiva. August 2002. Understanding BPEL4WS, Part 1.

1.	Invoke Web services.
2.	The caller waits for a message to operate on the service's interface to be invoked by an external service.
3.	This generates a response of an input/output operation.
4.	Waits for a certain amount of time.
5.	Copies data from one place to another.
6.	Indicates that an error occurred.
7.	Then terminates the service.
8.	Or else does nothing.

The notation looks something like this:

1. <invoke>

2. <receive>

3. <reply>

4. <wait>

5. <assign>

6. <throw> ...