Java™ Application Development on Linux - Dator

17.2 The IBM SWT Toolkit381Microsoft Windows. If you have ever written an X Window or MicrosoftWindows application in straight C (without a GUI framework library or classlibrary), you have written a main() function that contains an event loop. SWTactually puts simple method calls around this core message queue event loop.We’ll cover the details of this in the next section where we introduce theDisplay and Shell classes.17.2.6 “Hello, world” SWT StyleSWT consists mainly of classes that represent controls—such as buttons, textareas, scrollbars, and so on—and layout managers which are much like layoutmanagers in Swing. But there are two other classes: Display, which modelsthe interface between your Java application and the underlying windowingsystem, and Shell, which effectively represents a single window.The application in Example 17.1 is a parallel to the simple Swing programin the last chapter (Example 16.1).This simple program, like its parallel in the Swing chapter, is deceptive.Sure, this is a lot of code to say “Hello, world” but it is because what we aresetting up here is an event-driven program that must respond to any validuser input.17.2.6.1 Setting Up to Run an SWT <strong>Application</strong>One advantage of Swing that we haven’t pointed out up to now is that it is partof every Java runtime (well, not gcj; more on that later), so you have all theclasses on your classpath without any special setup. Not so with SWT. Theexact procedure for setting up to run an SWT application depends on whatdevelopment environment you are using.There is an excellent set of directions for running an SWT applicationunder Eclipse in the SWT FAQ. 8 No matter what your environment is, thereis a basic series of steps:1. Download the Eclipse SDK.2. Install it.8. http://dev.eclipse.org/viewcvs/index.cgi/~checkout~/platform-swt-home/faq.html?rev=1.83content-type=text/html#standalone. Note that this link is tothe current revision in CVS as of this writing. You should take a look at the parent page to seeif there is a newer revision.