Applications:

From the time you begin programming you start to develop a style of writing programs much the same as someone who writes stories develops a style. If you write software only for your own use and you will be the only one maintaining it, then the most important thing about your style is that it produces results you are happy with. If, however, you write software that will be extended and/or maintained by others there are some important elements you should incorporate into your style. Your success in this will have a direct impact on the amount of mean nasty e-mails you receive and your ability succeed and prosper in software development.

High quality in software, in large measure, dependants on the consistency with which it is written. Certainly, there are other factors that will impact on the quality of your programs, but for now I'll concentrate on consistency. Part of your style will need to be consistency; that is doing things in the same way. Part of this comes naturally, as I have never yet met someone that likes to rewrite code they have already written. The usual practice is to use and build libraries of standard objects and methods that can easily be pulled from a library and reused in a new program. All programming environments come with such libraries and provide a means for you to add your own libraries of objects and methods. This saves you the effort of rewriting code and saves on debugging since before you put something into the library you make sure it is thoroughly tested.

Applets require certain methods (as in behavior of a class). Good programming practice as taught by the Sun Java Tutorial and other sources of training require certain additional methods and practices. For instance, browsers depend on applets having methods for initialization (init()), to start the applet (start()), to stop the applet (stop()), and to destroy the applet (destroy()). Add to this elements like code that is always neat; that has lots of white space, lots of comments, the brackets line up, and the various elements of a class, function, object, or method are in predictable places. These put you well on the road to software that is written consistently.

Using this model for programming an applet with the defined control mechanisms and the other features described above will serve well for application programs as well. In case you haven't read the other articles in my Java pages yet, the difference between an applet and an application is: An application will run on a computer with out the need for a web browser. An Applet only runs in the context of a web browser under the direct control the web browser. As it turns out, it is very straightforward to take a program of this structure and make both applet and application versions. This is another way in which consistence can be brought to your program code. Now certainly I have written applets that I doubt I will ever want application versions of and visa versa. This doesn't negate the value of this addition consistency in writing style.

All Java applications require a main() method. This is where the Java Virtual Machine (JVM) looks to start execution. A program structured as described above can be used as an applet or an application. The application version will have a main() method which controls the application via the init(), start(), etc. methods that are part of the consistent structure. In the case of an applet, it may use space allocated on a web page to present itself. An application version would include a JFrame to be the main application window. In the case of the Java Toy Compulator, this program is an applet that already uses a JFrame to display the applet in a separate window from the browser. In this case the application version was simpler to make since the window for the application to use was already programmed in.

Java provides nicely for programming consistency. Further, both applet and application versions of a given program can be created that differ in predictable ways that further enhance consistency in program creation.





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