Database Reference
In-Depth Information
and Callback activities. One can add more activities between Receive and Callback
based on the business process and logic.
The following figure depicts the typical BPEL structure for synchronous and asyn-
chronous BPELs. The client receives the immediate response for a synchronous
BPEL and the delayed response for an asynchronous BPEL.
Use synchronous BPEL processes if the BPEL process requires a request-response
model. However, creating asynchronous processes is a more flexible and fault-toler-
ant practice that usually avoids blocking the WebLogic threads.
Note
Asynchronous services are a call-and-forget service. The response may not re-
turn for an asynchronous service. The client can immediately perform other pro-
cessing work after making an asynchronous service call and doesn't need to an-
ticipate a response immediately.
An update on a database is an example of a synchronous process. BPEL waits
until it completes the database update activity and then replies and completes
the process.
An example of an asynchronous process can be, getting a credit score from
a credit agency system. The asynchronous BPEL provides information about a
person to the credit agency and drops the operation. The asynchronous process
continues to do processing and it determines when to accept the data from the
credit agency.
