Basic Text Components - The Definitive Guide to Java Swing - page 545

Figure 15-12 shows the screen after typing some information into the text component.
Figure 15-12. NavigationFilter sample
Keymap Interface
In “MVC-speak,” the keymap property of the text component is the Controller part. It maps
KeyStroke objects to individual actions through the Keymap interface. (The KeyStroke class
was discussed in Chapter 2.) When you register the KeyStroke to the JTextComponent with
registerKeyboardAction() , as in the PopupSample program shown in Listing 15-9 earlier in
this chapter, the text component stores this mapping from KeyStroke to Action in a Keymap .
For instance, the Backspace key is mapped to delete the previous character. If you want to
add another binding, you just register another keystroke.
■ Note In reality, the Keymap is just a front to the ActionMap / InputMap pair. The JTextComponent
relies on some internal workings to indirectly use the ActionMap / InputMap classes.
You can also add actions for keystrokes directly to the Keymap . This allows you to share a
key map across multiple text components, as long as they all share the same extended behavior.
public interface Keymap {
// Properties
public Action[ ] getBoundActions();
public KeyStroke[ ] getBoundKeyStrokes();
public Action getDefaultAction();
public void setDefaultAction(Action action);
public String getName();
public Keymap getResolveParent();
public void setResolveParent(Keymap parent);
// Other methods
public void addActionForKeyStroke(KeyStroke keystroke, Action action);
public Action getAction(KeyStroke keystroke);
public KeyStroke[ ] getKeyStrokesForAction(Action action);
public boolean isLocallyDefined(KeyStroke keystroke);
public void removeBindings();
public void removeKeyStrokeBinding(KeyStroke keystroke);
}