C H A P T E R   3

Properties and Bindings

Heaven acts with vitality and persistence.
In correspondence with this
The superior person keeps himself vital without ceasing.

—I Ching

In Chapters 1 and 2, we introduced you to the JavaFX 2.0 platform. You downloaded the JavaFX 2.0 SDK and the JavaFX plugin for Netbeans. You wrote and ran your first JavaFX 2.0 GUI programs. You learned the fundamental building blocks of JavaFX 2.0: the Stage and Scene classes, and the Nodes that go into the Scene. And you have no doubt noticed the use of user-defined model classes to represent the application state and have that state communicated to the UI through properties and bindings.

In this chapter, we give you a guided tour of the JavaFX 2.0 properties and bindings framework. After recalling a little bit of history and presenting a motivating example that shows various ways that a JavaFX 2.0 Property can be used, we cover key concepts of the framework: Observable, ObservableValue, WritableValue, ReadOnlyProperty, Property, and Binding. We show you the capabilities offered by these fundamental interfaces of the framework. We then show you how Property objects are bound together, how Binding objects are built out of properties and other bindings—using the factory methods in the Bindings utility class, the fluent interface API, or going low-level by directly extending abstract classes that implement the Binding interface—and how they are used to easily propagate changes in one part of a program to other parts of the program without too much coding. We finish this chapter by introducing the JavaFX Beans naming convention, an extension of the original JavaBeans naming convention that makes organizing your data into encapsulated components an orderly affair.