Anonymous web server - Chapter 8 Object-Based Programming 411 8.9 Software Reusability
Chapter 8 Object-Based Programming 411 8.9 Software Reusability Java programmers concentrate on crafting new classes and reusing existing classes. Many class libraries exist, and others are being developed worldwide. Software is then constructed from existing, well-defined, carefully tested, well-documented, portable, widely available components. This kind of software reusability speeds the development of powerful, high-quality software. Rapid applications development (RAD) is of great interest today. Java programmers now have thousands of classes in the Java API from which to choose to help them implement Java programs. Indeed, Java is not just a programming language. It is a framework in which Java developers can work to achieve true reusability and rapid applications development. Java programmers can focus on the task at hand when developing their programs and leave the lower-level details to the classes of the Java API. For example, to write a program that draws graphics, a Java programmer does not require knowledge of graphics on every computer platform where the program will execute. Instead, a Java programmer concentrates on learning Java s graphics capabilities (which are quite substantial and growing) and writes a Java program that draws the graphics, using Java s API classes such as Graphics. When the program executes on a given computer, it is the job of the interpreter to translate Java commands into commands that the local computer can understand. The Java API classes enable Java programmers to bring new applications to market faster by using preexisting, tested components. Not only does this reduce development time, it also improves programmers ability to debug and maintain applications. To take advantage of Java s many capabilities, it is essential that programmers take the time to familiarize themselves with the variety of packages and classes in the Java API. There are many Web-based resources at java.sun.com to help you with this task. The primary resource for learning about the Java API is the Java API documentation, which can be found at java.sun.com/j2se/1.3/docs/api/index.html In addition, java.sun.com provides many other resources, including tutorials, articles and sites specific to individual Java topics. Java developers should also register (for free) at the Java Developer Connection developer.java.sun.com This site provides additional resources that Java developers will find useful, including more tutorials and articles, and links to other Java resources. See Appendix B for a more complete list of Java-related Internet and World Wide Web resources. Good Programming Practice 8.6 Avoid reinventing the wheel. Study the capabilities of the Java API. If the API already contains a class that meets the requirements of your program, use that class rather than creating your own. In general, to realize the full potential of software reusability, we need to improve cataloging schemes, licensing schemes, protection mechanisms that ensure master copies of classes are not corrupted, description schemes that system designers use to determine if existing objects meet their needs, browsing mechanisms that determine what classes are Copyright 1992 2002 by Deitel & Associates, Inc. All Rights Reserved. 7/3/01