6.8. Summary

This chapter starts with a general explanation of data pushing and moves on to cover topics that relate to messaging, messaging domains, and JMS. In the context of data pushing, polling, piggybacking, long polling, persistent connections, and Comet were discussed. The messaging domains of point-to-point communication and publish/subscribe interactions were described and compared. JMS is introduced and the essentials of the infrastructure, the administered objects, and the API were illustrated.

Then the chapter builds on an example that includes the usage of both JMSAdapter and the ActionScriptAdapter. Messaging within BlazeDS, the classes involved, the configurations, and custom classes were all explained with the help of this example. The example is the biggest part of the chapter. Although not necessarily complex, it brings most important features in BlazeDS to life.

The sample application can also be looked at as an aggregation of a few related but independents concepts, namely:

• Message-based integration between a Flex client and a Java server

• Use of JMS in conjunction with a Flex application

• Messaging between two Flex clients

• Usage of built-in messaging adapters in BlazeDS

After the entire example was presented, there was a small section on the two robust built-in messaging adapters, namely ActionScriptAdapter and JMSAdapter.

Finally there was a last, small section that focused on enhancements to BlazeDS for enterprise-grade data pushing. Continuations in Jetty were explored as an option for Comet implementation.

Hopefully, you are fairly familiar with the messaging features in BlazeDS after reading this chapter. I assume that you are inspired and excited to leverage this feature in building real-time Rich Internet Applications.