java.applet Reference.pdf

In this chapter:

• Introduction to the

Reference Chapters

• Package diagrams

java.applet Reference

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 pack-

age 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 1, 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

520

I NTRODUCTION

521

), 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 super-

classes. 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.

✩

Package diagrams

The following ﬁgures provide a visual representation of the relationships between

the classes in the AWT packages.

java.awt , as the mother of all AWT packages, is better represented by two dia-

grams, one for the graphics classes and one for the component and layout classes.

star (

522 java.applet Reference

java.awt.image

java.awt

Checkbox

Choice

List

ItemSelectable

Button

Panel

Canvas

ScrollPane

CheckboxGroup

Dialog

FileDialog

Container

Window

ImageObserver

Frame

Label

java.lang

Scrollbar

Adjustable

Component

TextArea

TextComponent

TextField

Object

MenuContainer

MenuComponent

MenuBar

MenuItem

PopupMenu

MenuShortcut

CheckboxMenuItem

FlowLayout

GridLayout

LayoutManager

Cloneable

GridBagConstraints

BorderLayout

LayoutManager2

java.io

CardLayout

Serializeable

GridBagLayout

KEY

CLASS

ABSTRACT CLASS

extends

INTERFACE

implements

Figure 18–1: Component and Layout classes of the java.awt package.

I NTRODUCTION

523

EventObject

AWTEvent

java.awt

java.awt.event

java.util

AWTEventMulticaster

ActionListener

java.lang

Color

SystemColor

AdjustmentListener

Cursor

ComponentListener

Dimension

ContainerListener

Object

Event

FocusListener

EventQueue

ItemListener

Font

KeyListener

FontMetrics

MouseListener

Graphics

MouseMotionListener

Image

TextListener

Cloneable

Insets

WindowListener

MediaTracker

Point

Polygon

PrintGraphics

PrintJob

Shape

Rectangle

Toolkit

Error

AWTError

java.io

Exception

AWTException

Serializeable

IllegalStateException

IllegalComponentStateException

KEY

CLASS

ABSTRACT CLASS

extends

INTERFACE

FINAL CLASS

implements

Figure 18–2: Graphics classes of java.awt package

524 java.applet Reference

java.lang

java.awt.image

ColorModel

DirectColorModel

Object

IndexColorModel

FilteredImageSource

ImageProducer

MemoryImageSource

Cloneable

CropImageFilter

ImageFilter

ReplicateScaleFilter

AreaAveragingScaleFilter

PixelGrabber

RGBImageFilter

ImageConsumer

ImageObserver

KEY

CLASS

ABSTRACT CLASS

extends

INTERFACE

INFREQUENTLY USED

implements

Figure 18–3: The java.awt.image package

java.lang

java.awt.datatransfer

Clipboard

Object

ClipboardOwner

DataFlavor

StringSelection

Transferable

Exception

UnsupportedFlavorException

KEY

CLASS

extends

INTERFACE

implements

Figure 18–4: The java.awt.datatransfer package

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