source: josm/trunk/src/org/openstreetmap/josm/gui/preferences/LanguagePreference.java@ 2553

// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.gui.preferences;

import static org.openstreetmap.josm.tools.I18n.tr;

import java.awt.Component;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Locale;
import java.util.logging.Logger;

import javax.swing.Box;
import javax.swing.DefaultComboBoxModel;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JComboBox;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.ListCellRenderer;
import javax.swing.SwingUtilities;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.gui.PleaseWaitRunnable;
import org.openstreetmap.josm.io.OsmTransferException;
import org.openstreetmap.josm.tools.GBC;
import org.openstreetmap.josm.tools.I18n;
import org.xml.sax.SAXException;

public class LanguagePreference implements PreferenceSetting {
    static private final Logger logger = Logger.getLogger(LanguagePreference.class.getName());

    public static class Factory implements PreferenceSettingFactory {
        public PreferenceSetting createPreferenceSetting() {
            return new LanguagePreference();
        }
    }

    /** the combo box with the available locales */
    private JComboBox langCombo;
    /** the model for the combo box */
    private LanguageComboBoxModel model;
    /** true, if the available translations have been loaded; false otherwise */
    private boolean translationsLoaded = false;

    public void addGui(final PreferenceDialog gui) {
        model = new LanguageComboBoxModel();
        langCombo = new JComboBox(model);
        langCombo.setRenderer(new LanguageCellRenderer(langCombo.getRenderer()));

        LafPreference lafPreference = gui.getSetting(LafPreference.class);
        final JPanel panel = lafPreference.panel;
        panel.add(new JLabel(tr("Language")), GBC.std().insets(20, 0, 0, 0));
        panel.add(GBC.glue(5,0), GBC.std().fill(GBC.HORIZONTAL));
        panel.add(langCombo, GBC.eol().fill(GBC.HORIZONTAL));
        panel.add(Box.createVerticalGlue(), GBC.eol().fill(GBC.BOTH));

        // this defers loading of available translations to the first time the tab
        // with the available translations is selected by the user
        //
        gui.displaycontent.addChangeListener(
                new ChangeListener() {
                    public void stateChanged(ChangeEvent e) {
                        int i = gui.displaycontent.getSelectedIndex();
                        String title = gui.displaycontent.getTitleAt(i);
                        if (title.equals(tr("Look and Feel"))) {
                            initiallyLoadAvailableTranslations();
                        }
                    }
                }
        );
    }

    public boolean ok() {
        if (!translationsLoaded)
            // keep the current language, don't update preferences
            return true;
        if(langCombo.getSelectedItem() == null)
            return Main.pref.put("language", null);
        else
            return Main.pref.put("language",
                    ((Locale)langCombo.getSelectedItem()).toString());
    }

    /**
     * Load available translations if not loaded yet.
     */
    public void initiallyLoadAvailableTranslations() {
        if (!translationsLoaded) {
            reloadAvailableTranslations();
        }
        translationsLoaded = true;
    }

    /**
     * Asynchronously loads available translations
     * 
     */
    protected void reloadAvailableTranslations() {
        Main.worker.submit(new AvailableTranslationsLoader());
    }

    /**
     * Asynchronous task to lookup the available translations.
     * 
     */
    private class AvailableTranslationsLoader extends PleaseWaitRunnable {
        public AvailableTranslationsLoader() {
            super(tr("Looking up available translations..."));
        }

        @Override
        protected void cancel() {
            // can't cancel
        }

        @Override
        protected void realRun() throws SAXException, IOException, OsmTransferException {
            final List<Locale> locales = new ArrayList<Locale>(
                    Arrays.asList(I18n.getAvailableTranslations(getProgressMonitor()))
            );
            locales.add(0,Locale.ENGLISH);
            Runnable r = new Runnable() {
                public void run() {
                    model.setAvailableLocales(locales);
                    model.selectLanguage(Main.pref.get("language"));
                }
            };
            try {
                SwingUtilities.invokeAndWait(r);
            } catch(InvocationTargetException e) {
                throw new RuntimeException(e.getCause());
            } catch(InterruptedException e) {
                throw new RuntimeException(e);
            }
        }

        @Override
        protected void finish() {}
    }

    private static class LanguageComboBoxModel extends DefaultComboBoxModel {
        private final List<Locale> data = new ArrayList<Locale>();

        public LanguageComboBoxModel() {}

        public void setAvailableLocales(List<Locale> locales) {
            data.clear();
            if (locales != null) {
                data.add(null); // the default locale
                data.addAll(locales);
            }
            fireContentsChanged(this, 0, getSize());
        }

        public void selectLanguage(String language) {
            setSelectedItem(null);
            if (language != null) {
                for (Locale locale: data) {
                    if (locale == null) {
                        continue;
                    }
                    if (locale.toString().equals(language)) {
                        setSelectedItem(locale);
                        return;
                    }
                }
            }
        }

        @Override
        public Object getElementAt(int index) {
            return data.get(index);
        }

        @Override
        public int getSize() {
            return data.size();
        }
    }

    static private class LanguageCellRenderer extends DefaultListCellRenderer {
        private ListCellRenderer dispatch;
        public LanguageCellRenderer(ListCellRenderer dispatch) {
            this.dispatch = dispatch;
        }
        @Override
        public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected,
                boolean cellHasFocus) {
            Locale l = (Locale) value;
            return dispatch.getListCellRendererComponent(list,
                    l == null ? tr("Default (Auto determined)") : l.getDisplayName(),
                            index, isSelected, cellHasFocus);
        }
    }
}