Java Reference
In-Depth Information
• The parts components in turn can send messages to their own inventory and order
components to update their inventories and to order new parts from suppliers.
• Both the factory and the parts components can send messages to the accounting
component to update budget numbers.
• The business can publish updated catalog items to its sales force.
Using messaging for these tasks allows the various components to interact with one an-
other efficiently, without tying up network or other resources.
Figure 20-1
illustrates how
this simple example might work.
FIGURE 20-1. Messaging in an Enterprise Application
Manufacturing is only one example of how an enterprise can use the JMS API. Retail ap-
plications, financial services applications, health services applications, and many others
can make use of messaging.
How Does the JMS API Work with the Java EE Platform?
When the JMS API was introduced in 1998, its most important purpose was to allow Java
applications to access existing messaging-oriented middleware (MOM) systems, such as
MQSeries from IBM. Since that time, many vendors have adopted and implemented the
JMS API, so a JMS product can now provide a complete messaging capability for an en-
terprise.
Beginning with the 1.3 release of the Java EE platform, the JMS API has been an integral
part of the platform, and application developers have been able to use messaging with Java
EE components.
The JMS API in the Java EE platform has the following features.
• Application clients, Enterprise JavaBeans (EJB) components, and web components
can send or synchronously receive a JMS message. Application clients can in ad-
