JTextComponent - A Text-Editing Lightweight Component

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Swinging Duke

A Lightweight Text-Editing Component

The support of text in AWT prior to Swing was quite limited; basically, text support was a thin interface mapped over the plain-text support provided by the native platform. This design provided the benefit of internationalization support that was offered by the native system, but it failed to meet the needs of many developers. When developers take it upon themselves to create their own support, they often leave out such features as support for internationalization, and they can then have a difficult time upgrading their code to take advantage of such features as Java 2D support. In Swing, the JTextComponent class is designed to provide a 100% pure Java text solution that fills in the gaps left by the text support provided in the previous API.

Goals

These are some of the goals that are aimed for in the Swing implementation of the JTextComponent class:

To support the previous text API as much as possible, to make conversion of existing software as easy as possible.
To provide a rich set of components ranging from simple to complex applications so that features orthogonal to the type of text application (such as internationalization, key-binding preferences, and the like) are uniformly available. This goal effectively means that a capable set of interface definitions are needed for every aspect of a text-oriented editor so that implementations can be modified substantially to meet particular domain-specific needs.
To provide Swing's pluggable look-and-feel capabilities in a robust manner. A text component places additional needs upon a system with a pluggable look and feel -- beyond the needs of most other kinds of components, such as button components. A wholesale replacement of the look-and-feel such as that provided by the UIFactory is not always the kind of customization that is most desirable for a text component, which can have a relatively complex model on which a view is based. To refine the usefulness of a complex text component, it might be desirable to plug portions of the view to alternative implementations.

Incompatibilities with java.awt.TextComponent

TextEvent and TextListener have been replaced by the DocumentEvent and DocumentListener interfaces. The DocumentEvent interface provides substantially more information about the nature of the change, so that observers can efficiently update themselves to reflect the change.

The JTextComponent API

The JTextComponent API is generated by JavaDoc. It contains the bulk of the specification.