Chapter 8: Application Development

This chapter will give practical advice on how to use certain development tools to build a pervasive solution for the WebSphere Portal Server.

Some of the tools introduced here are also used to build the sample application for the book. You will find detailed descriptions of these tools and even some step-by-step instructions on how to use them to build the sample application.

8.1 Application development methodology

Today, it is quite common in the industry to develop object-oriented software via an iterative and incremental process. This approach has different roots. For more information, refer to Object-Oriented Analysis and Design with Applications by Grady Booch, Object-Oriented Software Engineering by Ivar Jacobson, and Object-Oriented Modeling and Design by James Rumbaugh.

There is no defined standard process for development that everyone uses. Different teams typically adopt a recognized process using a vendor methodology or their services team methodology. IBM Global Services has its own methodology used in customer engagements that covers the development process. Rational Software Corporation , for example, uses its Rational Unified Process .

These methodologies generally divide the development process into different phases. Each phase is done in a sequential manner and is subdivided into further smaller phases. Some phases are only run through once. Others are done over and over again, forming the iterative and incremental part of the development process. The actual process and which phases you use might differ slightly depending on the development team or organization that uses the process. We can divide the whole process into the following phases:

• Solution outline

• Macro design

• Micro design

• Build cycle

• Deployment

Figure 8-1: Development process overview

In the Solution Outline phase, you decide the scope of the project, explore what the essential business needs are, come up with an idea of the base architecture, and get the commitment from the project sponsor to start.

Then you start with the macro design, which concentrates on the detailed requirements gathering, business process modeling, high-level analysis and design, base architecture, and a plan for the subsequent development phases, including a development release plan. These two phases are usually done once in a project.

Now the iterative and incremental part of the development starts. For each release of the developed e-business application, the micro design, build cycle, and deployment phases are completed. Usually, a subset of use cases that has to be developed to meet a part of the system requirements make up a release. Use cases are grouped according to relevance and timeliness of functionality. The releases are defined in the project plan produced in the previous phase. A release can be an internal one that is not deployed to any users. This is quite common for early stages of big projects. Others, such as alpha or beta releases, might be deployed to a certain number of test users. It might take several iterations until a first official release of the application is deployed to the users. In turn , there are often several releases to the users until all requirements are met, plus maintenance releases to fix errors and other defects.

For more information on the application development process in the context of IBM Patterns for e-business, refer to the publication Self-Service Patterns using WebSphere Application Server V4.0 , SG24-6175.