Preface

This book has been my full-time passion for more than a year. After Sun closed its office in Colorado Springs in August of 1997, I decided to forego traditional employment to give the Graphic Java series my complete attention. I was determined that the Swing volume would be the definitive guide to Swing, which meant that it had to be the most comprehensive, accurate and insightful Swing book available. I believe that to be the case, but of course, you will be the final judge.

Before I began writing, I spent a considerable amount of effort designing a book that would be beneficial to Swing novices in addition to developers with some Swing experience. As a software developer that has used numerous object oriented GUI frameworks, I realized that the fastest way to climb a framework's learning curve is to study code examples that illustrate specific concepts. As a result, code examples are the foundation upon which this book is built; nearly 300 code examples are discussed in detail—an average of approximately one code example every 5 pages.

However, code in examples and of themselves, cannot suffice as a reference for developers that have advanced along the Swing learning curve. As a result, every Swing component discussion is accompanied by a component summary that includes class diagrams, an examination of the component's properties and events and a class summary that discusses the public and protected methods implemented by the component.

The first part of this book explores fundamental aspects of Swing including:

• Swing applets and applications

• Swing and multithreading

• Swing's Model-View-Controller architecture

• Pluggable Look And Feel

• The JComponent class

• Borders, icons and actions

• Miscellaneous features including timers and Swing utilities

The second part of the book examines Swing's components in detail. Numerous code examples are discussed for every Swing component, from labels and buttons to tables, trees and the text package. For example, more than 150 pages containing 25 code examples are dedicated to the table component, and 120 pages and 20 code examples illustrate how to get the most out of the tree component.

Audience

This book assumes that the reader has a good grasp of the Java language including recent additions to the language such as inner classes. This book also assumes a rudimentary understanding of the AWT; specifically, the delegation event model and the Component and Container classes upon which all Swing components are based. See "Graphic Java 1.1 Mastering the JFC Volume I: AWT" for a thorough investigation of AWT infrastructure and components.

How To Use This Book

Before diving into the Swing components, it is useful to have an understanding of fundamental concepts such as Swing's Model-View-Controller (MVC) design and pluggable look and feel. The former is discussed in “Swing Component Architecture” and the latter is covered in “Pluggable Look and Feel”. It is also important to understand the services provided by the JComponent class, which is the ultimate superclass of all lightweight Swing components. The JComponent class is examined in “The JComponent Class”.

Component Summaries

Each Swing component is introduced with numerous code examples that illustrate various component features. Code examples are followed by component summaries, such as the JScrollPane component summary that is partially listed below.

Component summaries begin with a listing of the component's model, UI delegate, renderer and editor, in addition to the events fired by the component. If a component is a replacement for an AWT component, the AWT component is also listed.

Component Summary 13-1 JScrollPane

The static relationships that a component maintains with other objects is illustrated with a class diagram, such as the class diagram for the JScrollPane class shown above. Class diagrams are introduced in Appendix A, Class Diagrams.

Properties

Property tables, such as the property table for the JScrollPane class shown below, are used to communicate a component's properties. Property tables include property names, the property's data type and whether a property is boolean, bound (a property change event is fired when the property is changed), simple (no events are fired when the property is changed), constrained (changes to the property can be vetoed), or indexed (a parameter, usually an integer, is used to access to property).

Some properties can be specified when a component is instantiated, and a component may provide setter and getter methods for a property. The manner in which a property can be specified is listed in the Access column of a property table.

Property tables also include a column for property default values.

Property tables are followed by a short description of each of the properties listed in the table.

^[1] b = boolean / B = bound (fires PropertyChangeEvent) / C = constrained/ I = indexed / S = simple / Ch = fires ChangeEvent

^[2] C = settable at construction time / G = getter method / S = setter method

^[5] L&F = look and feel dependent

^[3] getColumnHeader.getView() returns the column header view

^[6] JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED

^[4] getRowHeader.getView() returns the row header view

^[7] JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED

columnHeader— An instance of JViewport for the column header.

columnHeaderView— An instance of Component used as the column header viewport's view.

corner— A component that is displayed in one of the scrollpane's corners. The corner is specified by one of the following strings:

• ScrollPaneConstants.UPPER_LEFT_CORNER

• ScrollPaneConstants.LOWER_LEFT_CORNER

• ScrollPaneConstants.UPPER_RIGHT_CORNER

• ScrollPaneConstants.LOWER_RIGHT_CORNER

horizontalScrollbar— The horizontal scrollbar used by the scrollpane. The scrollbar is an instance of JScrollPane.ScrollBar, an extension of JScrollBar that takes into account whether the view contained in the scrollpane implements the Scrollable interface.

The remaining property descriptions for the JScrollPane class are omitted.

Events

Code examples are presented that illustrate event handling for a component. For example, the Tree chapter provides five code examples that illustrate handling of tree mouse, editing, selection, and expansion events.

Class Summaries

Each component summary concludes with a class summary that provides descriptions of the component's constructors and methods, such as the class summary for the JScrollPane class listed below.

Class Summary 13-2 JScrollPane

Constructors

public JScrollPane()

public JScrollPane(int vsbPolicy, int hsbPolicy)
public JScrollPane(Component view)
public JScrollPane(Component view, int vsbPolicy, int hsbPolicy)

JScrollPane provides four constructors. The integer values passed to JScrollPane constructors represent the vertical and horizontal scrollbar display policies, in that order. The component passed to the constructors is used as the viewport's view, meaning it is the component that is scrolled by the scrollpane.

The no-argument constructor constructs a scrollpane with a null component for the viewport's view, and scrollbar display policies that display both the horizontal and vertical scrollbars as needed.

Methods

Creation Methods

public JScrollBar createHorizontalScrollBar()
public JScrollBar createVerticalScrollBar()
protected JViewport createViewport()

Like most Swing components, JScrollPane provides create ... methods that create its subcomponents. Unlike most Swing components however, JScrollPane implements the methods that create its scrollbars as public instead of protected because the methods are invoked from the scrollpane's UI delegate.

The createHorizontalScrollBar and createVerticalScrollBar methods both return instances of JScrollPane.ScrollBar, which is an extension of JScrollBar that takes into account whether the scrollpane's view implements the Scrollable interface. See Interface Summary 13-2 for more information on the Scrollable interface.

The createViewport method returns an instance of JViewport that is used as the scrollpane's default viewport.

As with all Swing components that implement create ... methods, the methods can be overridden in extension classes to replace the default sub-components with custom versions.

The remaining method descriptions for the JScrollPane class are omitted.

Swing Bugs

Swing has come a long way in terms of quality. The early beta releases contained numerous bugs, many of which have subsequently been fixed. However, like any software, Swing still has its share of bugs. Throughout this book, I have tried to point out as many bugs as possible so that developers can avoid the frustration of debugging code only to discover that a problem is due to a Swing bug.

It is also important to keep in mind that this book is based on Swing 1.1 FCS. As we went to press, a 1.1.1 version of Swing was released that was mostly a bug fix release. Therefore, it is a certainty that some of the bugs cited in this book will have been fixed by the time this book is on the shelves.

Using the CDROM

The CD in the back of the book contains the following:

• 1.1.7 JDK and Swing 1.1.1

• 1.2 JDK and Swing 1.1 FCS

• Code examples from this book

Swing and The JDK

As mentioned previously, Swing 1.1.1 is mostly a bug fix release. Swing 1.1.1 does not work with the 1.2 JDK, and therefore the 1.1.7 JDK is included on the CD. Swing 1.1 FCS works with both the 1.1.7 and 1.2 versions of the JDK.

Code Examples From the Book

All of the code examples in this book that are accompanied by a CD-ROM icon^[1] are included on the CD in the back of the book. Figure P-1 shows the directory structure for the code examples. A directory exists for every chapter in the book,^[2] and subdirectories are included for each example, which should make it trivial to locate examples. For instance, Example 3-1 can be found in the booksrc/chapters/3/1 directory.

^[1] See Table P-2.

^[2] Except for chapter 1, which does not contain any code examples.

Every example is compiled and ready to run. Some of the directories representing code examples contain a README.txt file if the examples exhibit bugs or have been modified from their listing in the book.

The CD also contains two versions of the GridBagLab application that comes with “Graphic Java 1.1 Mastering the JFC Volume I: AWT”. One version uses external windows and another uses Swing internal frames. The application provides an example of a fairly complete Swing application and illustrates the use of Swing internal frames. Additionally, the application can be used to explore the intricacies of the GridBagLayout layout manager.

Applets Vs. Applications

Most of the code examples discussed in this book are applets, but a fair percentage of examples are applications. Applications are typically implemented instead of applets either because files are manipulated or dialogs are shown—applets have restricted access to files, and under JDK 1.2 dialogs displayed from an applet contain a warning string. Sometimes applications are implemented instead of applets simply for the sake of variety. Nearly all of the applications discussed in this book that do not manipulate files can easily be rewritten as applets. See “Applets Vs. Applications” for a discussion of the differences between Swing applets and applications.

Conventions Used in This Book

Table P-1 shows the coding conventions used in this book.

Note that, for the most part, methods are referred to without their arguments; however, arguments are included when the discussion warrants them.

Table P-2 shows the typographic conventions used in this book.

Table P-2. Typographic Conventions

Typeface or Symbol	Description
	Indicates that the accompanying code, command, or file is available on the CD that accompanies this book.
courier	Indicates a command, file name, class name, method, argument, Java keyword, HTML tag, file content, or code excerpt.
bold courier	Indicates a sample command-line entry.
italics	Indicates definitions, emphasis, a book title, or a variable that should be replaced with a valid value.