Working with Locales in Swing (with change at runtime)?

Question

I thought about the best way to implement localisation with runtime in Swing.

I currently solve the problem like that:

JMenu menuData = new JMenu("Data");
    menuData.setName("mainframe.menu.data"); // property key
    localeChangedListener.add(menuData);

The LocaleChangedListener:

public class SwingLocaleChangedListener implements LocaleChangedListener {

    private ArrayList<AbstractButton>   abstractButtons;

    @Override
    public void localeChanged(ResourceBundle rb) {
        logger.info("Locale changed to '" + rb.getLocale() + "'");
        for (AbstractButton b : abstractButtons) {
            b.setText(rb.getString(b.getName()));
            b.setComponentOrientation(ComponentOrientation.getOrientation(rb.getLocale())); //EDIT: Line added
        }

    }

    public boolean add(AbstractButton b) {
        initAbstractButtons();
        return abstractButtons.add(b);
    }

    private void initAbstractButtons() {
        if (abstractButtons == null) {
            this.abstractButtons = new ArrayList<AbstractButton>();
        }
    }
}

And the registration of the Listener:

public class GuiBundleManager {

    private String                  filePrefix  = "language.lang";
    private ResourceBundle          rb         = null;
    private LocaleChangedListener   listener    = null;

    private static GuiBundleManager instance    = null;

    private GuiBundleManager() { 
        setLocale(Locale.getDefault());
    }

    public String getString(String key) {
        return rb.getString(key);
    }

    public String[] getStringArray(String key) {
        return rb.getStringArray(key);
    }

    public Locale getLocale() {
        return rb.getLocale();
    }

    public void setLocale(Locale l) {
        rb = ResourceBundle.getBundle(filePrefix, l);
        if (listener != null) {
            listener.localeChanged(rb);
        }
    }

    public LocaleChangedListener getLocaleChangedListener() {
        return listener;
    }

    public void setLocaleChangedListener(LocaleChangedListener listener) {
        this.listener = listener;
        if (listener != null) {
            listener.localeChanged(rb);
        }
    }

    public static GuiBundleManager get() {
        if (instance == null) {
            instance = new GuiBundleManager();
        }
        return instance;
    }
}

Another way I'm thinking of is using Component.setLocale() combined with an PropertyChangedListener:

public abstract class GUIComponentFactory {

    public JLabel createLocalisedJLabel(final String key) {
        final JLabel label = new JLabel(GuiBundleManager.get().getString(key));
        label.addPropertyChangeListener("locale", new PropertyChangeListener() {

            @Override
            public void propertyChange(PropertyChangeEvent e) {
                label.setText(GuiBundleManager.get().getString(key));
                label.setComponentOrientation(ComponentOrientation.getOrientation(e.getNewValue())); //Edit: Line added
                for(Component c : getComponents()){
                    c.setLocale(e.getNewValue());
                }
            }
        });
                return label;
    }
    .
    .
    .
}

Answer 1

Consider applyComponentOrientation(), which recursively "Sets the ComponentOrientation property of this component and all components contained within it." Examples may be found here.

Answer 2

Whatever approach you finally decide upon: you don't have to handle the resourceBundles yourself. Instead, add them to the UIManager and query that for the localized values:

// edited: it's the defaults which take the bundle, my bad I didn't check core api
// SwingX has a UIManagerExt which takes it directly :-)
UIManager.getDefaults().addResourceBundle("com.xypackage.resources.MyBundle");
...
label.setText(UIManager.get(key, label.getLocale());

There used to be (didn't check if it's fixed) a bug which prevented this to work reliably in webstartables.