language is selectable in the settings

src/main/java/de/neemann/digital/core/element/Keys.java

@@ -2,6 +2,8 @@ package de.neemann.digital.core.element;
 
 import de.neemann.digital.core.io.IntFormat;
 import de.neemann.digital.core.memory.DataField;
+import de.neemann.digital.lang.Language;
+import de.neemann.digital.lang.Languages;
 
 import java.util.Locale;
 
@@ -201,6 +203,13 @@ public final class Keys {
     public static final Key<Boolean> SETTINGS_IEEE_SHAPES
             = new Key<>("IEEEShapes", Locale.getDefault().getLanguage().equals(Locale.US.getLanguage()));
 
+    /**
+     * The Gui Language
+     */
+    public static final Key<Language> SETTINGS_LANGUAGE
+            = new Key<>("Language", Languages.getInstance().getDefault());
+
+
     /**
      * output format for numbers
      */

src/main/java/de/neemann/digital/draw/elements/Circuit.java

@@ -18,6 +18,7 @@ import de.neemann.digital.draw.shapes.Drawable;
 import de.neemann.digital.draw.shapes.ShapeFactory;
 import de.neemann.digital.gui.components.AttributeDialog;
 import de.neemann.digital.lang.Lang;
+import de.neemann.digital.lang.Language;
 
 import java.awt.*;
 import java.io.*;
@@ -60,6 +61,8 @@ public class Circuit {
         xStream.alias("intFormat", IntFormat.class);
         xStream.alias("rotation", Rotation.class);
         xStream.aliasAttribute(Rotation.class, "rotation", "rotation");
+        xStream.alias("language", Language.class);
+        xStream.aliasAttribute(Language.class, "name", "name");
         xStream.alias("vector", Vector.class);
         xStream.aliasAttribute(Vector.class, "x", "x");
         xStream.aliasAttribute(Vector.class, "y", "y");

src/main/java/de/neemann/digital/gui/Main.java

@@ -386,8 +386,10 @@ public class Main extends JFrame implements ClosingWindowListener.ConfirmSave, E
         ToolTipAction editSettings = new ToolTipAction(Lang.get("menu_editSettings")) {
             @Override
             public void actionPerformed(ActionEvent e) {
-                if (new AttributeDialog(Main.this, Settings.SETTINGS_KEYS, Settings.getInstance().getAttributes()).showDialog())
+                if (new AttributeDialog(Main.this, Settings.SETTINGS_KEYS, Settings.getInstance().getAttributes()).showDialog()) {
+                    Lang.setLanguage(Settings.getInstance().getAttributes().get(Keys.SETTINGS_LANGUAGE));
                     JOptionPane.showMessageDialog(Main.this, Lang.get("msg_restartNeeded"));
+                }
             }
         }.setToolTip(Lang.get("menu_editSettings_tt"));
 

src/main/java/de/neemann/digital/gui/Settings.java

@@ -30,6 +30,7 @@ public final class Settings implements AttributeListener {
 
     static {
         INT_LIST.add(Keys.SETTINGS_IEEE_SHAPES);
+        INT_LIST.add(Keys.SETTINGS_LANGUAGE);
     }
 
     private static final class SettingsHolder {

src/main/java/de/neemann/digital/gui/components/EditorFactory.java

@@ -7,6 +7,8 @@ import de.neemann.digital.core.io.IntFormat;
 import de.neemann.digital.core.memory.DataField;
 import de.neemann.digital.core.memory.ROM;
 import de.neemann.digital.lang.Lang;
+import de.neemann.digital.lang.Language;
+import de.neemann.digital.lang.Languages;
 import de.neemann.gui.ErrorMessage;
 import de.neemann.gui.ToolTipAction;
 
@@ -36,6 +38,7 @@ public final class EditorFactory {
         add(DataField.class, DataFieldEditor.class);
         add(Rotation.class, RotationEditor.class);
         add(IntFormat.class, IntFormatsEditor.class);
+        add(Language.class, LanguageEditor.class);
     }
 
     private <T> void add(Class<T> clazz, Class<? extends Editor<T>> editor) {
@@ -305,4 +308,22 @@ public final class EditorFactory {
         }
     }
 
+    private static class LanguageEditor extends LabelEditor<Language> {
+        private JComboBox comb;
+
+        public LanguageEditor(Language language, Key<Rotation> key) {
+            comb = new JComboBox<>(Languages.getInstance().getSupportedLanguages());
+            comb.setSelectedIndex(Languages.getInstance().getIndexOf(language));
+        }
+
+        @Override
+        protected JComponent getComponent(ElementAttributes elementAttributes) {
+            return comb;
+        }
+
+        @Override
+        public Language getValue() {
+            return Languages.getInstance().getByIndex(comb.getSelectedIndex());
+        }
+    }
 }

src/main/java/de/neemann/digital/lang/Lang.java

@@ -4,11 +4,14 @@ import java.text.MessageFormat;
 import java.util.Locale;
 import java.util.MissingResourceException;
 import java.util.ResourceBundle;
+import java.util.prefs.Preferences;
 
 /**
  * @author hneemann
  */
 public final class Lang {
+    private static final Preferences PREFS = Preferences.userRoot().node("dig");
+    private static final String LANGUAGE = "lang";
 
     private static class InstanceHolder {
         static final Lang INSTANCE = new Lang();
@@ -25,6 +28,16 @@ public final class Lang {
         return InstanceHolder.INSTANCE.getKey(key, params);
     }
 
+
+    /**
+     * Sets the GUI language
+     *
+     * @param language the language
+     */
+    public static void setLanguage(Language language) {
+        PREFS.put(LANGUAGE, language.getName());
+    }
+
     /**
      * gets an internationalized string
      *
@@ -40,9 +53,10 @@ public final class Lang {
     private ResourceBundle localeBundle;
 
     private Lang() {
-        Locale currentLocale = Locale.getDefault();
         defaultBundle = ResourceBundle.getBundle("lang/lang", Locale.ENGLISH);
         try {
+            String lang = PREFS.get(LANGUAGE, null);
+            Locale currentLocale = Languages.getInstance().getLocaleByName(lang);
             localeBundle = ResourceBundle.getBundle("lang/lang", currentLocale);
         } catch (MissingResourceException e) {
         }

src/main/java/de/neemann/digital/lang/Language.java

@@ -0,0 +1,54 @@
+package de.neemann.digital.lang;
+
+import java.util.Locale;
+
+/**
+ * @author hneemann
+ */
+public final class Language {
+
+    private final String name;
+    private transient Locale locale;
+
+    /**
+     * Creates a new instance
+     *
+     * @param name the languages name
+     */
+    public Language(String name) {
+        this.name = name;
+    }
+
+    /**
+     * Creates a new instance
+     *
+     * @param locale the locale
+     */
+    public Language(Locale locale) {
+        this(locale.getLanguage());
+        this.locale = locale;
+    }
+
+    @Override
+    public String toString() {
+        return name;
+    }
+
+    /**
+     * Returns the locale
+     *
+     * @return the locale
+     */
+    Locale getLocale() {
+        return locale;
+    }
+
+    /**
+     * returns the name
+     *
+     * @return the name
+     */
+    public String getName() {
+        return name;
+    }
+}

src/main/java/de/neemann/digital/lang/Languages.java

@@ -0,0 +1,106 @@
+package de.neemann.digital.lang;
+
+import java.util.ArrayList;
+import java.util.Locale;
+
+/**
+ * @author hneemann
+ */
+public final class Languages {
+
+    private static final class InstanceHolder {
+        private static final Languages INSTANCE = new Languages();
+    }
+
+    /**
+     * @return the languages instance
+     */
+    public static Languages getInstance() {
+        return InstanceHolder.INSTANCE;
+    }
+
+    private final ArrayList<Language> list = new ArrayList<>();
+    private String[] strArray;
+
+    private Languages() {
+        add(Locale.US);
+        add(Locale.GERMANY);
+    }
+
+    private void add(Locale locale) {
+        list.add(new Language(locale));
+    }
+
+    /**
+     * Returns a list of all supported languages
+     *
+     * @return the languages list
+     */
+    public String[] getSupportedLanguages() {
+        if (strArray == null) {
+            strArray = new String[list.size()];
+            for (int i = 0; i < strArray.length; i++)
+                strArray[i] = list.get(i).getLocale().getDisplayName();
+        }
+        return strArray;
+    }
+
+    /**
+     * Returns the index of the given language
+     *
+     * @param language the language
+     * @return the index
+     */
+    public int getIndexOf(Language language) {
+        for (int i = 0; i < list.size(); i++)
+            if (list.get(i).getName().equals(language.getName()))
+                return i;
+        return 0;
+    }
+
+    /**
+     * Returns the language by the languages index
+     *
+     * @param index the index
+     * @return the language
+     */
+    public Language getByIndex(int index) {
+        return list.get(index);
+    }
+
+    /**
+     * Returns the default language
+     *
+     * @return the systems language, if there is a translation, US otherwise
+     */
+    public Language getDefault() {
+        String lang = Locale.getDefault().getLanguage();
+        for (Language l : list) {
+            if (l.getLocale().getLanguage().equals(lang))
+                return l;
+        }
+        return list.get(0);
+    }
+
+    /**
+     * Returns a locale by the given name
+     *
+     * @param lang the language name
+     * @return the locale matching the language
+     */
+    public Locale getLocaleByName(String lang) {
+        return getLanguageByName(lang).getLocale();
+    }
+
+    private Language getLanguageByName(String lang) {
+        if (lang == null)
+            return getDefault();
+
+        for (Language l : list)
+            if (l.getName().equals(lang))
+                return l;
+
+        return getDefault();
+    }
+
+}

src/main/resources/lang/lang_de.properties

@@ -57,6 +57,8 @@ key_intFormat_dec=Dezimal
 key_intFormat_hex=Hexadezimal
 key_intFormat_bin=Bin\u00E4r
 key_intFormat_ascii=ASCII
+key_Language=Sprache
+
 attr_openCircuitLabel=Enthaltene Schaltung:
 attr_openCircuit=Anzeigen
 attr_openCircuit_tt=\u00D6ffnet die Schaltung in einem neuen Fenster.

src/main/resources/lang/lang_en.properties

@@ -51,6 +51,8 @@ key_intFormat_dec=decimal
 key_intFormat_hex=hex
 key_intFormat_bin=bin
 key_intFormat_ascii=ascii
+key_Language=Language
+
 attr_openCircuitLabel=Included circuit:
 attr_openCircuit=Show
 attr_openCircuit_tt=Opens the circuit in a new window.