Chapter 2. Architecture of the commerce.connect products 13
call.connect messaging is implemented using IBM’s implementation of the Java Message
Service (JMS), which itself uses MQSeries as the underlying messaging facility. You can
learn more about JMS at:
http://java.sun.com/products/jms/index.html
Figure 2-3 shows how call.connect uses messaging.
Figure 2-3 call.connect messaging usage
Adding a Sales Order Line scenario
This example explains what happens when an order line is added to a Sales Order by an
operator:
1. The SalesOrder EJB processes the addline in the normal way.
2. The Business Event Addline is published.
3. Control returns back to the client ready for further input.
4. The SalesOrder subscriber is a separate process that listens for SalesOrder events and
receives the Addline message.
5. The subscriber calls back into the SalesOrder EJB to perform a “check for unusual
quantity” request to see if the customer normally orders this amount of stock for the item
concerned.
6. If the quantity ordered is unusual, the SalesOrder subscriber notifies the PC client by
making a call back into the client. The client displays the notification text in the UI status
bar.
SalesOrder
Subscriber
WebSphere Application
Server
SalesOrder
SalesOrder
EJB
EJB
PC Client
Event
Queue
Client request
Order information
Call Business
Logic
Publish SalesOrder
Business Event
