Essential Series. Springer-Verlag London Ltd.

Transcription

1 Essential Series Springer-Verlag London Ltd.

2 Also in this series: Essential Visual Basic 4.0 fast Essential Delphi 2.0 fast Essential Java fast Essential Visual Basic 5.0 fast Duncan Reed and Peter Thomas Essential HTML fast Essential Delphi 3 fast John Hunt Essential JavaBeans fast John Vince Essential Virtual Reality fast Essential Visual J fast

3 Essential Java 2 fast How to develop applications and applets with Java 2, Springer

4 , BSc(Hons), MPhil, PhD Department of Computer and Information Sciences, De Montfort University Kents Hill Campus, Hammerwood Gate, Kents Hill Milton Keynes, MK7 6HP, UK ISBN British Library Cataloguing in Publication Data Cowell, John, Essential Java 2 fast: how to develop applications and applets with Java 2. - (Essential series) 1.J ava (Computer program language) I.Title 005.2'76'2 ISBN Library of Congress Cataloging-in-Publication Data Cowell, John, Essential Java 2 fast: how to develop applications and applets with Java 2/. p. cm. ISBN DOI / Title. QA76.73.J38C '762--dc21 ISBN (ebook) CIP Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may on1y be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms oflicences issued by the Copyright Licensing Agency. Enquiries concerning reproduction outside those terms should be sent to the publishers. Springer-V erlag London 1999 Originally published by Springer-Verlag London Berlin Heidelberg in 1999 Microsoft, MS, Visual Basic, Windows, Windows 95 and Windows 98 are trademarks of Microsoft Corporation Ltd. Java and Hot Java are trademarks of Sun Microsystems Corporation Ltd. Pentium is a trademark of Intel Corporation Ud. The use of registered names, trademarks etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant laws and regulations and therefore free for general use. The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. Typesetting: Camera-ready by author 34/ Printed on acid-free paper SPIN

5 1 WHY JAVA 2 IS SPECIAL... 1 Introduction Is this book for you?... 2 What you need to run Java How to use this book... 3 An object-oriented approach... 4 Conventions AN OBJECT-ORIENTED APPLICATION... 6 Introduction... 6 A first application... 7 What can go wrong?... 8 How does the application work?... 8 Classes and objects... 9 The main method What's new Running the application Using classes and objects Naming conventions THE JAVA LANGUAGE Introduction Applications and applets Comments Terminating Java statements Data types The integer data types The floating point data types The boolean data type..., The char data type The String data type Names in Java Declaring data Arithmetic in Java Mixing data types Casting v

6 vi Assignment operators Using strings in Java Operator precedence Displaying information on your screen BRANCHING AND LOOPING Introduction The If... else statement Logical operators The switch statement Block statements Looping The for loop The while loop The do... while loop The break statement Arrays CREATING AND USING CLASSES AND OBJECTS Introduction... '" The Account class The displaydetails method The incredit method... '" The credit and debit methods The main method Using constructors Encapsulating data Calling methods Command line arguments for applications USIN'G.APPLETS Introduction... '" Writing applets The APPLET tag Key methods of the Applet class The init method The start method The stop method The destroy method The paint method Command line arguments for applets... 51

7 vii 7 THE GRAPHICS, COLOR AND FONT CLASSES Introduction The co-ordinate frame Importing classes The Graphics class Drawing lines Drawing rectangles Drawing circles and ovals Drawing arcs Drawing polygons The Color class Creating colours Displaying text and changing fonts Displaying images INHERITANCE AND POLYMORPHISM Introduction A hierarchy of computer components Defining the Memory subclass Polymorphism The MBoard class Extending a subclass Class and instance variables Static methods Overloading methods Access control Interfaces MOUSE AND KEYBOARD EVENTS Introduction The MouseEvent class The MouseListener interface Which button was pressed? The MouseAdapter class The MouseMotionListener interface The KeyEvent class The KeyAdapter class The KeyListener interface THE AWT COMPONENTS Introduction Event-driven programming

8 viii The A WT classes The Button class Handling events The Label class... '" The Scrollbar class Handling Scrollbar events The Checkbox class The List class Multiple selection in List objects The TextComponent class The TextArea class Using the TextListener interface The TextField class The Canvas class THE LAYOUT MANAGERS Introduction The FlowLayout class The BorderLayout class The CardLayout class The GridLayout class The GridBagLayout class WINDOWS, DIALOGS AND MENUS Introduction The Container class The Frame class Creating an application which uses a frame The WindowListener interface Creating an applet which uses a frame The MenuBar class The Dialog class The FileDialog class The Panel class THE SWING COMPONENTS Introduction Differences between Swing and A WT components The Swing components The Swing container classes The AbstractButton class The Swing and A WT buttons Changing the look and feel

9 ix The JButton class The IToggleButton, JRadioButton and JCheclcBox classes Displaying text The llabel class The ITextField class The ITextArea class The llist class..., The JColorChooser class The JFileChooser class JAVA EXCEPTIONS Introduction The Exception class The try and catch clauses... ", 198 Throwing an exception Creating new exceptions Throwing without catching WRITING THREADED APPLICATIONS 203 Introduction Pre-emptive scheduling.., The Runnable interface The Thread class Synchronizing threads The Thread class Creating animation The bouncing ball applet FILES AND STREAMS Introduction The File class The InputStream and OutputStream classes The DatalnputStream and DataOutputStream classes Using the DataOutputStream class Using the DatalnputStream class Reading text flies Reading from the keyboard Converting strings to other data types IN"DEX