Linux Application Development For The Enterprise (Charles River Media Programming)

Similar to Chapter 5, this is also a lengthy chapter, covering many aspects of desktop and database development using one of the very powerful RAD tools—Borland Kylix. The chapter started with a mention of the desktop development scenario on the Linux platform and then shifted its attention toward the Borland Kylix platform, providing an overview of the type of applications that can be developed using this platform. Then the discussion continued with the goal of introducing the IDE and its components to Linux novices, as many veteran programmers might already be familiar with this platform. The menus, toolbars, Component palette, Object Inspector, Form Designer, code editor, and other wizards such as Project Options dialog and Object Repository are discussed in this section. The different files created in a Kylix project are identified with their default file extensions, with regard to both the Delphi and C++ compilers.

The CLX component library is the next topic discussed in this chapter, where the different sublibraries such as BaseCLX, VisualCLX, DataCLX, and NetCLX are presented. A majority of the discussion focuses on the first three component sets; the last set of components will be discussed in a future chapter, based on the subject matter relevance. A brief presentation of some of the most frequently used objects such as string lists, object lists, and streams is given, followed by a detailed discussion on the CLX object event model and exception handling topics. An example project is developed to demonstrate the exception handling concepts.

The discussion then turns toward developing GUI applications using this platform. The system global variables and resources such as application, screen, cursor, and clipboard are discussed to considerable extent, followed by the most powerful feature: drag-and-drop. A sample project is developed to demonstrate the implementation of drag-and-drop in Kylix applications. The next major topic in the chapter is developing database applications, in which the dbExpress framework is discussed in depth. The concepts of client-server development, two-tier and three-tier applications, client dataset, and provider components are the main topics of this section, in addition to a thorough presentation on datasets and their characteristics and the use of data modules. Two example projects are built to illustrate the database development. One example presents details on how to establish connection with an Enterprise class database system such as Oracle, while the other example concentrates on bringing out the power of a client dataset component as an in-memory dataset and demonstrating how it enables us to build briefcase-style applications. The examples are built using Delphi and C++ languages alternatively, and using Red Hat Linux 9.0 and SuSE Linux 8.2 alternatively.

The last topic presented in this chapter is developing desktop applications using Java IDEs. For the purpose of discussion and building a sample application, Borland JBuilder8 IDE is presented; however, the discussion is applicable to several other Java IDEs available currently. It has been mentioned that using an IDE for developing Java applications is very useful and productive, as it eliminates a large amount of mundane work and is also supportive of team development.

This chapter, coupled with Chapter 5, will give programmers a very good handle on the RAD-based development concepts, using a couple of the most powerful tools (Kylix and JBuilder) available for Linux programmers today.