Core Concepts

A BPEL process consists of steps. Each step is called an activity. BPEL supports basic and structured activities. Basic activities represent basic constructs and are used for common tasks, such as those listed below:

• Invoking other web services, using <invoke>

• Waiting for the client to invoke the business process through sending a message, using <receive> (receiving a request)

• Generating a response for synchronous operations, using <reply>

• Manipulating data variables, using <assign>

• Indicating faults and exceptions, using <throw>

• Waiting for some time, using <wait>

• Terminating the entire process, using <terminate>

We can then combine these and other basic activities and define complex algorithms that exactly specify the steps of a business process. To combine basic activities BPEL supports several structured activities. The most important are:

• Sequence (<sequence>) for defining a set of activities that will be invoked in an ordered...