Synchronous web services provide an immediate response to an invocation. BPEL can connect to synchronous web services through a partner link, send data, and receive the reply in the same synchronous invocation.

A synchronous invocation requires the following components:

• Partner link

  Defines the location and the role of the web services with which the BPEL process service component connects to perform tasks, and the variables used to carry information between the web service and the BPEL process service component. A partner link is required for each web service that the BPEL process service component calls. You can create partner links in several ways, including the following:

  • In the SOA Composite Editor, when you drag a SOAP service from the Technology section of the Components window into the Exposed Services or External References swimlane. For more information, see Adding Service Binding Components or Adding Reference Binding Components.

  • In Oracle BPEL Designer, when you drag a Partner Link icon from the BPEL Constructs section of the Components window into the Partner Links swimlane. This second method is described in this chapter.

• Invoke activity

  Opens a port in the BPEL process service component to send and receive data. For example, this port is used to retrieve information verifying that a customer has acceptable credit using a credit card authorization service. For synchronous callbacks, only one port is needed for both the send and receive functions.