Java Swing, 2nd Edition

Creating Your Own Component

So you’ve been bitten by the bug. There isn’t a component anywhere in the Swing library that fits your needs, and you’ve decided that it’s time to write your own. Unfortunately, you’re dreading the prospect of creating one. Maybe you’ve heard somewhere that it is a complex task, or your jaw is still bouncing on the floor after browsing through some of the Swing component source code.

This section should help dispel those fears. Creating your own component isn’t hard—just extend the JComponent class with one of your own and away you go! On the other hand, getting it to behave or even display itself correctly can take a bit of patience and fine-tuning. So here is a step-by-step guide to steer you clear of the hidden “gotchas” that lurk in the task of creating a component.

When creating Swing components, it’s always a good idea to adhere to the JavaBeans standards. Not only can such components be used programmatically, but they can also be plugged into one of the growing number of GUI-builder tools. Therefore, whenever possible, we try to highlight areas that you can work on to make your components more JavaBeans-friendly.

Getting Started

First things first. If you haven’t already, you should read through the JComponent section of Chapter 3. This will help you get a feel for the kinds of features you can expect in a Swing component and which ones you might want to use (or even disable) in your own component. If you are creating a component that is intended ...