18.1 Introduction to the Reference Chapters

The preceding seventeen chapters cover just about all there is to know about AWT. We have tried to organize them logically, and provide all the information that you would expect in a reference manual--plus much more in the way of examples and practical information about how to do things effectively. However, there are many times when you just need a reference book, pure and simple: one that's organized alphabetically, and where you can find any method if you know the class and package that it belongs to, without having to second guess the author's organizational approach. That's what the rest of this book provides. It's designed to help you if you need to look something up quickly, and find a brief but accurate summary of what it does. In these sections, the emphasis is on brief; if you want a longer description, look in the body of the book.

The reference sections describe the following packages:

• java.applet (Chapter 18, java.applet Reference)

• java.awt (Chapter 19, java.awt Reference)

• java.awt.datatransfer (Chapter 20, java.awt.datatransfer Reference)

• java.awt.event (Chapter 21, java.awt.event Reference)

• java.awt.image (Chapter 22, java.awt.image Reference)

• java.awt.peer (Chapter 23, java.awt.peer Reference)

Within each package, classes and interfaces are listed alphabetically. There is a description and a pseudo-code definition for each class or interface. Each variable and method is listed and described. New Java 1.1 classes are marked with a black star (), as are new methods and new variables. Of course, if a class is new, all its methods are new. We didn't mark individual methods in new classes. Methods that are deprecated in Java 1.1 are marked with a white star ().

Inheritance presents a significant problem with documenting object-oriented libraries, because the bulk of a class's methods tend to be hiding in the superclasses. Even if you're very familiar with object-oriented software development, when you're trying to look up a method under the pressure of some deadline, it's easy to forget that you need to look at the superclasses in addition to the class you're interested in itself. Nowhere is this problem worse than in AWT, where some classes (in particular, components and containers) inherit well over 100 methods, and provide few methods of their own. For example, the Button class contains seven public methods, none of which happens to be setFont(). The font used to display a button's label is certainly settable--but to find it, you have to look in the superclass Component.

So far, we haven't found a way around this problem. The description of each class has an abbreviated class hierarchy diagram, showing superclasses (all the way back to Object), immediate subclasses, and the interfaces that the class implements. Ideally, it would be nice to have a list of all the inherited methods--and in other parts of Java, that's possible. For AWT, the lists would be longer than the rest of this book, much too long to be practical, or even genuinely useful. Someday, electronic documentation may be able to solve this problem, but we're not there yet.