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Java Coffee Break Newsletter Volume 2 Issue 08
Java Coffee Break Newsletter Volume 2, Issue 8
http://www.javacoffeebreak.com/
ISSN 1442-3790
================================================================
In this issue
* We've moved - to www.javacoffeebreak.com
* Java in the news
* Book Reviews - Java Programming for Beginners
* Tutorial - Get your GUI Swinging!
* Q&A : How do I minimize and restore frames and JFrames?
================================================================
We've moved location
Over the past two years of publication, the Java Coffee Break
has gone from strength to strength. What started out as a small
hobby site has become a fully fledged e-zine publication. I'd
like to thank all my readers, both of the online site and this
newsletter, for their interest and support over the years.
With the large increase in visitors to the site, and subscribers
to this newsletter, the time has come for the Java Coffee Break
to move to its own domain name. You can now find all of our
published articles, tutorials, reviews & FAQ's at the a new
location,
http://www.javacoffeebreak.com/
================================================================
In the News
Here are a selection of recent news items that may be of
interest to Java developers.
/*/ HotSpot Performance Engine 1.0.1 now available
Sun has released an early access version of their HotSpot
performance engine, through the Java Developer Connection
(JDC). The list of features it boasts is impressive to say
the least
- "pauseless" garbage collection, and a fourfold increase
over that of Java2.
- dynamic compilation, and on-the-fly optimization of
performance critical code.
To download HotSpot for yourself, goto
http://developer.java.sun.com/developer/
================================================================
Book Reviews - Java Programming for Beginners
Java Gently
Author : Judy Bishop
Publisher : Addison-Wesley
ISBN : 0201342979
*This review relates to the first edition*
Java Gently teaches the principles of computer programming, and
the Java language, rather than just teaching Java in isolation.
Unlike other books, it requires no previous programming
experience, because it teaches fundamental concepts alongside
Java. It has a good emphasis on object orientated design; class
diagrams are used extensively throughout the book to make it easy
to understand how examples work. Working through the book will
teach you how to program - not just how to write simple applets.
This isn't a quick guide to Java, so not everyone will appreciate
this approach.
Examples in the book teach a wide range of topics, from simple
concepts like conditional branching and looping, to high level
concepts like exception handling, abstraction, data structures
and networking. The approach taken by the book introduces topics
gradually, and makes it easy to pick up the skills needed to
program in Java. Other books attempt to teach a narrow range of
topics, such as Java applets or user interfaces within a very
short time-frame, whereas this book has a more broad scope that
will make future programming easier. If Java is your first
programming language, and you're considering it as a career, you
should make this one of your first books.--David Reilly.
For more information about this title, or to order it, visit
http://www.davidreilly.com/goto.cgi?isbn=0201342979
Beginning Java 2
Author : Ivor Horton
Publisher : Wrox Press
ISBN : 1861002238
Review Courtesy of Amazon.com
Beginning Java 2 is one of the two best introductory Java 2 books
available. (The other is Peter van der Linden's Just Java 1.2.)
Assuming nothing more than curiosity and tenacity, this book
explains how to create programs with the Java programming
language. And not just simple, academic programs either--the
applets and applications that Ivor Horton describes in later
chapters take advantage of the latest features of Java 2.
After a brief introduction to the characteristics of Java,
Beginning Java 2 digs into variables, data types, operators,
control structures, and basic Java syntax--the stuff you
absolutely have to understand in order to get anything done.
Horton then explains streams, files, and threads before getting
into the graphical stuff, where he details how to build
attractive, functional user interfaces with the Swing components
(with solid coverage of the Java 2 event model). Later chapters
address Java2D graphics and database connectivity. The author
treats object orientation as integral to the rest of Java
programming, which is appropriate to the language.
Readers get to see how concepts work, as regular Try It Out
sections include illustrative code listings and the resulting
output. The author and publisher deserve kudos for printing the
complete source code of example programs rather than just key
excerpts. These example programs also appear on the publisher's
Web site. --David Wall
For more information about this title, or to order it, visit
http://www.davidreilly.com/goto.cgi?isbn=1861002238
Just Java 1.2
Author : Peter van der Linden
Publisher : Prentice Hall
ISBN : 0130105341
Review Courtesy of Amazon.com
So, you're starting from zero in an effort to learn the Java
programming language. What book will help you most? Just Java 1.2
should be on your desktop. It's one of a select group of
introductory Java books that honestly earns its cover price.
Shying away from complicated aspects of the language that are
seldom used in most practical situations, Peter van der Linden
focuses his considerable teaching skills upon the parts of the
language you really need to understand in order to be a good Java
programmer. He covers basic structure and syntax very well, and
gives similarly excellent attention to object orientation and the
means by which Java implements it. Applets, Beans, input/output
streams, basic graphics, Swing, and security all get superb
coverage.
In short, this book explains everything you really need to know
in order to write useful Java programs. With sharp text and very
good example programs, the author shows you how to get things
done. In the process, van der Linden--a funny guy--pauses often
to show you how to make an origami water-bomber or comment upon
software error messages like "runt packet."
The CD-ROM that comes with this book deserves much praise, as
well. Packed with honestly useful tools and all of the author's
examples, it employs a fine HTML-based interface that other books
ought to imitate. --David Wall.
For more information about this title, or to order it, visit
http://www.davidreilly.com/goto.cgi?isbn=0130105341
================================================================
Get your GUI Swinging!
By David Reilly
Swing offers Java developers greater flexibility and
control over the design of graphical user interfaces
(GUI), as well as a suite of graphical components
ranging from buttons to tables and trees. In this
tutorial, we'll help you to put the GRR in swinger!
Learn how to use Swing in your applications, to add
that professional touch.
What is Swing?
With the release of the Java 2 platform (and the Java Development
Kit 1.2), developers now have access to a wider range of
graphical user interface components, and greater flexibility and
control over their appearance. The previous graphics toolkit, the
Abstract Windowing Toolkit (AWT), was sufficient for simple
applets, but was a poor substitute for a commercial quality suite
of components. As part of the Java Foundation Classes (JFC), the
Swing library of components rectifies the shortcomings of AWT,
and gives developers the ability to create professional graphical
user interfaces that will be the envy of developers using other
languages like Visual Basic or Delphi.
The Swing API isn't a replacement for the AWT. Swing is designed
to be used in conjunction with existing AWT components, and to
compliment it. Not only does Swing offer new components, but it
also offers greater control over their appearance, and a
customizable "look and feel" (L&F), that allows applications to
swing from a "Java look and feel" to a "Windows look and feel"
on-the-fly. Developers even have the ability to create their own
L&F, for custom applications or games.
Getting started with Swing
Developing applications with Swing user-interfaces is actually
quite easy. You can even convert your existing applications over
to use the new Swing components. In this tutorial, we'll show how
to get your applications swinging.
Learning about Swing
The best way to learn about Swing is to actually use an
application that has a Swing GUI. A good starting place is the
SwingSet demo, that is shipped with JDK1.2.
[Figure 1 - SwingSet Demo]
http://www.javacoffeebreak.com/tutorials/swing/swing1.gif
If you don't already have JDK1.2 installed, you'll need to
install it to work with Swing applications. The latest version of
JDK1.2 can be found at http://java.sun.com/
Running the SwingSet Demo
The demo can be found in the demo/jfc/SwingSet directory, located
under your JDK1.2 installation directory. From a DOS Prompt or
shell window, change to this directory then run the SwingSet
application.
c:\>cd \jdk1.2\demo\jfc\SwingSet
c:\jdk1.2\demo\jfc\SwingSet>java SwingSet
The first thing you should notice is that the demonstration takes
awhile to load - a window with a progress bar will be shown as
the demonstration loads. The progress bar component is a nice way
of letting users know that a slow application is still chugging
along, and hasn't fallen over ;)
Once the demonstration loads, you can then click on different tab
buttons to view the various components and behaviors that make up
the Swing API. Take some time to experiment and click on some of
the components - you'll be pleasantly surprised at the
functionality that's available.
While you have the SwingSet demo running, take a look at the menu
options. You can now trigger a menu using only the keyboard (e.g.
ALT-F for the File menu). Take a look at the Options menu, and
the radio buttons provided. These allow you to dynamically change
the look-and-feel of components at run-time.
[Figure 2 - L&F Options]
http://www.javacoffeebreak.com/tutorials/swing/swing2.gif
Switch between the Java L&F (also referred to as 'Metal'), and
the Motif/Windows L&F. You'll notice that all of the components
(including menus) change appearance. This is a very powerful
feature of Swing, and gives users control over which GUI style is
used. Personally, I think that the Metal L&F is very comfortable
to use, though end-users may prefer to stick with Windows L&F.
Once you've had a play around with Swing, you'll be reluctant to
go back to the older AWT components. Remember however that only
the Java 2 Platform supports Swing (though older Java 1.1 Virtual
Machines can still run Swing if you include the components in the
codebase of your application, for a large download). For the
moment at least, it rules out developing Swing applets for normal
browsing, unless the Java Plug-in is used to run them under a
Java 2 Virtual Machine.
For the complete tutorial, including diagrams, goto
http://www.javacoffeebreak.com/tutorials/swing/
================================================================
Q&A: How do I minimize and restore frames and JFrames?
This question stumped me when I first took a look at it. There is
no minimize or restore method in JFrame, or java.awt.Frame for
that matter. However, I knew there had to be a way - as JFrames
frequently need to be restored programmatically. I suspected that
the problem was a difference in terminology, and after a little
searching, found the answer.
JFrame inherits the setState method from java.awt.Frame. This
method allows you to change the state of a window from
"iconified", back to "normal". This is, in actual fact, minimize
and restore - but the documentation uses different terms. To
minimize or restore a window, we simply call the setState method,
and pass it a state parameter to indicate whether we want to
minimize or restore the window.
For example, to minimize a Frame (or subclass, such as JFrame),
we pass the 'iconified' parameter
myFrame.setState ( Frame.ICONIFIED );
To restore the frame to its normal state, we call the setState
method with the 'normal' parameter
myFrame.setState ( Frame.NORMAL );
To demonstrate this effect, I've written a small demonstration,
which you can compile and run. In the following example, a new
frame is created, and then minimized. After a short delay, it is
restored again.
import java.awt.*;
public class FrameTest
{
public static void main (String args[]) throws
Exception
{
// Create a test frame
Frame frame = new Frame("Hello");
frame.add ( new Label("Minimize demo") );
frame.pack();
// Show the frame
frame.setVisible (true);
// Sleep for 5 seconds, then minimize
Thread.sleep (5000);
frame.setState ( Frame.ICONIFIED );
// Sleep for 5 seconds, then restore
Thread.sleep (5000);
frame.setState ( Frame.NORMAL );
// Sleep for 5 seconds, then kill window
Thread.sleep (5000);
frame.setVisible (false);
frame.dispose();
// Terminate test
System.exit(0);
}
}
================================================================
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