Next Generation Wireless Applications: Creating Mobile Applications in a Web 2.0 and Mobile 2.0 World, 2nd Edition

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J2EE Presentation Layer

In Chapter 6 we looked at how we can build scalable and robust mobile applications using a software platform technology called J2EE. The essence of J2EE was the division of software into infrastructure services and business-specific services, as shown in Figure 8.1. The infrastructure services are inherent in the J2EE platform. They enable us to produce mobile applications that are multi-user, scalable, secure, fully redundant, database-connected, and so on, without having to include all these functions in the software we write.

In Chapter 7 we looked at protocols to support the link between the devices and the platform. Our main focus was on link–fetch–response paradigms supported by IP protocols like HTTP/TCP and wireless equivalents from the WAP family, like WSP/WTP.

In this chapter, we shall examine in more detail how J2EE supports these protocols and how we might structure our business software to take advantage of the power of J2EE whilst simultaneously supporting protocols like HTTP.

We shall also look in more detail at how the browser processes the content fetched from the server. We have mentioned the browser application as a key component in many mobile services, but we have not yet looked at how it works in any detail, or how it ties back to the J2EE programming paradigm. There are also some challenges that are very specific to the mobile environment, such as how to cope with many different devices types. This is a challenge for our application ...