added translation capabilities

src/me/teridax/jcash/Main.java

@@ -3,6 +3,7 @@ package me.teridax.jcash;
 import me.teridax.jcash.gui.Loader;
 import me.teridax.jcash.gui.account.AccountController;
 import me.teridax.jcash.gui.login.LoginController;
+import me.teridax.jcash.lang.Locales;
 
 import javax.swing.*;
 import java.util.Objects;
@@ -12,6 +13,7 @@ import static javax.swing.JOptionPane.ERROR_MESSAGE;
 import static javax.swing.JOptionPane.showMessageDialog;
 import static me.teridax.jcash.Logging.LOGGER;
 import static me.teridax.jcash.Logging.initializeSystemLogger;
+import static me.teridax.jcash.lang.Translator.translate;
 
 public final class Main {
 
@@ -28,7 +30,7 @@ public final class Main {
     private Main() {
         // create main window and set defaults
         this.window = new JFrame();
-        this.window.setTitle("Bankautomat");
+        this.window.setTitle(translate("Cashmachine"));
         this.window.setLocationByPlatform(true);
         this.window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     }
@@ -36,6 +38,8 @@ public final class Main {
     public static void main(String[] args) {
         initializeSystemLogger(Level.FINE);
 
+        Locales.autodetectDefaultLocale();
+
         // create main instance and show the login screen
         instance();
         getInstance().showLoginScreen();
@@ -97,7 +101,7 @@ public final class Main {
 
             } catch (IllegalStateException e) {
                 LOGGER.fine("Unable to show login mask: " + e.getMessage());
-                showMessageDialog(null, e.getMessage(), "Closing JCash", ERROR_MESSAGE);
+                showMessageDialog(null, e.getMessage(), translate("Closing JCash"), ERROR_MESSAGE);
                 System.exit(0);
             }
         });
@@ -107,7 +111,7 @@ public final class Main {
      * Logs the user out of the database, hiding the main window.
      */
     public void logout() {
-        window.setContentPane(new JLabel("you're logged out"));
+        window.setContentPane(new JLabel(translate("you're logged out")));
         window.setVisible(false);
     }
 }

src/me/teridax/jcash/gui/Loader.java

@@ -2,6 +2,7 @@ package me.teridax.jcash.gui;
 
 import me.teridax.jcash.Logging;
 import me.teridax.jcash.banking.management.BankingManagementSystem;
+import me.teridax.jcash.lang.Translator;
 
 import javax.swing.*;
 import javax.swing.filechooser.FileNameExtensionFilter;
@@ -34,7 +35,7 @@ public class Loader {
         fileChooser.setDialogType(JFileChooser.OPEN_DIALOG);
         fileChooser.setAcceptAllFileFilterUsed(false);
 
-        if (fileChooser.showDialog(null, "Load database") == APPROVE_OPTION) {
+        if (fileChooser.showDialog(null, Translator.translate("Load database")) == APPROVE_OPTION) {
             // parse file content
             try {
                 return BankingManagementSystem.loadFromCsv(fileChooser.getSelectedFile().toPath());

src/me/teridax/jcash/gui/account/AccountView.java

@@ -10,6 +10,7 @@ import javax.swing.*;
 import java.awt.*;
 
 import static javax.swing.SwingConstants.RIGHT;
+import static me.teridax.jcash.lang.Translator.translate;
 
 public class AccountView extends JPanel {
 
@@ -52,10 +53,10 @@ public class AccountView extends JPanel {
 
         this.type.setText(account.getClass().getSimpleName());
         if (account instanceof CurrentAccount) {;
-            this.typeSpecialLabel.setText("Overdraft");
+            this.typeSpecialLabel.setText(translate("Overdraft"));
             this.typeSpecialProperty.setText( StringDecoder.LOCAL_NUMBER_FORMAT.format(((CurrentAccount) account).getOverdraft()) + " €");
         } else if (account instanceof SavingsAccount) {
-            this.typeSpecialLabel.setText("Interest rate");
+            this.typeSpecialLabel.setText(translate("Interest rate"));
             this.typeSpecialProperty.setText( ((SavingsAccount) account).getInterest() + " %" );
         } else {
             Logging.LOGGER.severe("Type of new primary account cannot be determined: " + account.getClass().getName());
@@ -84,14 +85,14 @@ public class AccountView extends JPanel {
         accountSelectionPanel.add(iban, BorderLayout.CENTER);
         accountSelectionPanel.add(accountSelection, BorderLayout.EAST);
 
-        addInputRow(constraints, content, accountSelectionPanel, 1, new JLabel("IBAN", RIGHT));
+        addInputRow(constraints, content, accountSelectionPanel, 1, new JLabel(translate("IBAN"), RIGHT));
-        addInputRow(constraints, content, name, 2, new JLabel("Name/Family-name", RIGHT));
+        addInputRow(constraints, content, name, 2, new JLabel(translate("Name/Family-name"), RIGHT));
-        addInputRow(constraints, content, address, 3, new JLabel("Address", RIGHT));
+        addInputRow(constraints, content, address, 3, new JLabel(translate("Address"), RIGHT));
-        addInputRow(constraints, content, bankName, 4, new JLabel("Bank", RIGHT));
+        addInputRow(constraints, content, bankName, 4, new JLabel(translate("Bank"), RIGHT));
-        addInputRow(constraints, content, blz, 5, new JLabel("BLZ", RIGHT));
+        addInputRow(constraints, content, blz, 5, new JLabel(translate("BLZ"), RIGHT));
-        addInputRow(constraints, content, type, 6, new JLabel("Account", RIGHT));
+        addInputRow(constraints, content, type, 6, new JLabel(translate("Account"), RIGHT));
         addInputRow(constraints, content, typeSpecialProperty, 7, typeSpecialLabel);
-        addInputRow(constraints, content, balance, 8, new JLabel("Balance", RIGHT));
+        addInputRow(constraints, content, balance, 8, new JLabel(translate("Balance"), RIGHT));
 
         var buttonPanel = Box.createHorizontalBox();
         buttonPanel.add(Box.createHorizontalStrut(4));
@@ -129,10 +130,10 @@ public class AccountView extends JPanel {
 
         this.accountSelection = new JComboBox<>();
 
-        this.logout = new JButton("Logout");
+        this.logout = new JButton(translate("Logout"));
-        this.transfer = new JButton("Transfer");
+        this.transfer = new JButton(translate("Transfer"));
-        this.deposit = new JButton("Deposit");
+        this.deposit = new JButton(translate("Deposit"));
-        this.takeoff = new JButton("Takeoff");
+        this.takeoff = new JButton(translate("Takeoff"));
     }
 
     /**

src/me/teridax/jcash/gui/deposit/DepositView.java

@@ -8,6 +8,8 @@ import java.awt.*;
 import java.text.NumberFormat;
 import java.text.ParseException;
 
+import static me.teridax.jcash.lang.Translator.translate;
+
 public class DepositView {
 
     private JDialog dialog;
@@ -22,7 +24,7 @@ public class DepositView {
 
     public void showDialog() {
         dialog.setModalityType(Dialog.ModalityType.APPLICATION_MODAL);
-        dialog.setTitle("Deposit money");
+        dialog.setTitle(translate("Deposit money"));
         dialog.pack();
         dialog.setResizable(false);
         dialog.setLocationRelativeTo(null);
@@ -43,7 +45,7 @@ public class DepositView {
         c.fill = GridBagConstraints.HORIZONTAL;
         c.anchor = GridBagConstraints.CENTER;
         c.insets = new Insets(4, 4, 4, 4);
-        dialog.getContentPane().add(new JLabel("Deposit money"), c);
+        dialog.getContentPane().add(new JLabel(translate("Deposit money")), c);
 
         c.gridx = 0;
         c.gridy = 1;
@@ -51,7 +53,7 @@ public class DepositView {
         c.fill = GridBagConstraints.NONE;
         c.anchor = GridBagConstraints.LAST_LINE_END;
         c.weightx = 0;
-        dialog.getContentPane().add(new JLabel("Value", SwingConstants.RIGHT), c);
+        dialog.getContentPane().add(new JLabel(translate("Value"), SwingConstants.RIGHT), c);
 
         c.gridx = 1;
         c.gridy = 1;
@@ -83,8 +85,8 @@ public class DepositView {
     private void createComponents() {
         this.dialog = new JDialog();
 
-        this.cancel = new JButton("Cancel");
+        this.cancel = new JButton(translate("Cancel"));
-        this.deposit = new JButton("Deposit");
+        this.deposit = new JButton(translate("Deposit"));
         this.value = new JFormattedTextField(StringDecoder.LOCAL_NUMBER_FORMAT);
 
         this.dialog.setContentPane(new JPanel(new GridBagLayout()));

src/me/teridax/jcash/gui/login/LoginController.java

@@ -8,6 +8,7 @@ import java.util.Optional;
 
 import static javax.swing.JOptionPane.ERROR_MESSAGE;
 import static javax.swing.JOptionPane.showMessageDialog;
+import static me.teridax.jcash.lang.Translator.translate;
 
 public class LoginController {
 
@@ -52,14 +53,14 @@ public class LoginController {
         var iban = this.getIban();
         if (iban.isEmpty()) {
             Logging.LOGGER.severe("IBAN is invalid: " + iban);
-            showMessageDialog(null, "invalid IBAN", "Faulty login attempt", ERROR_MESSAGE);
+            showMessageDialog(null, translate("Invalid IBAN"), translate("Faulty login attempt"), ERROR_MESSAGE);
             return;
         }
 
         var pin = this.getPin();
         if (pin.isEmpty()) {
             Logging.LOGGER.severe("PIN is invalid: " + pin);
-            showMessageDialog(null, "invalid pin", "Faulty login attempt", ERROR_MESSAGE);
+            showMessageDialog(null, translate("Invalid pin"), translate("Faulty login attempt"), ERROR_MESSAGE);
             return;
         }
 
@@ -68,7 +69,7 @@ public class LoginController {
             this.listener.onAccountSelected(account.get());
         } else {
             Logging.LOGGER.severe("invalid login credentials: " + iban + " / " + pin);
-            showMessageDialog(null, "invalid login credentials", "Faulty login attempt", ERROR_MESSAGE);
+            showMessageDialog(null, translate("Invalid login credentials"), translate("Faulty login attempt"), ERROR_MESSAGE);
         }
     }
 

src/me/teridax/jcash/gui/login/LoginView.java

@@ -5,6 +5,8 @@ import javax.swing.text.NumberFormatter;
 import java.awt.*;
 import java.text.NumberFormat;
 
+import static me.teridax.jcash.lang.Translator.translate;
+
 public class LoginView extends JPanel {
 
     private JFormattedTextField blz;
@@ -23,16 +25,16 @@ public class LoginView extends JPanel {
         this.setBorder(BorderFactory.createEmptyBorder(8,8,8,8));
         this.setLayout(new BorderLayout(16, 16));
         this.add(new JScrollPane(content), BorderLayout.CENTER);
-        this.add(new JLabel("Bankautomat"), BorderLayout.NORTH);
+        this.add(new JLabel(translate("Cashmachine")), BorderLayout.NORTH);
 
         var constraints = new GridBagConstraints();
 
         constraints.gridwidth = 4;
         constraints.insets = new Insets(12,12,12,12);
 
-        addInputRow(constraints, content, blz, 1, "BLZ");
+        addInputRow(constraints, content, blz, 1, translate("BLZ"));
-        addInputRow(constraints, content, iban, 2, "IBAN");
+        addInputRow(constraints, content, iban, 2, translate("IBAN"));
-        addInputRow(constraints, content, pin, 3, "PIN");
+        addInputRow(constraints, content, pin, 3, translate("PIN"));
 
         constraints.gridy = 4;
         constraints.anchor = GridBagConstraints.PAGE_END;
@@ -46,7 +48,7 @@ public class LoginView extends JPanel {
         this.blz = new JFormattedTextField();
         this.iban = new JFormattedTextField(getNumberFormat());
         this.pin = new JPasswordField();
-        this.login = new JButton("Login");
+        this.login = new JButton(translate("Login"));
     }
 
     private NumberFormatter getNumberFormat() {

src/me/teridax/jcash/gui/takeoff/TakeoffDialog.java

@@ -5,6 +5,7 @@ import me.teridax.jcash.banking.accounts.Account;
 
 import static javax.swing.JOptionPane.ERROR_MESSAGE;
 import static javax.swing.JOptionPane.showMessageDialog;
+import static me.teridax.jcash.lang.Translator.translate;
 
 public class TakeoffDialog {
 
@@ -30,7 +31,7 @@ public class TakeoffDialog {
             view.dispose();
         } catch (IllegalArgumentException ex) {
             Logging.LOGGER.severe("Could not take off money: " + ex.getMessage());
-            showMessageDialog(null, "Reason: " + ex.getMessage(), "Could not take off money", ERROR_MESSAGE);
+            showMessageDialog(null, "Reason: " + ex.getMessage(), translate("Could not take off money"), ERROR_MESSAGE);
         }
     }
 }

src/me/teridax/jcash/gui/takeoff/TakeoffView.java

@@ -9,6 +9,7 @@ import java.text.ParseException;
 
 import static javax.swing.JOptionPane.ERROR_MESSAGE;
 import static javax.swing.JOptionPane.showMessageDialog;
+import static me.teridax.jcash.lang.Translator.translate;
 
 public class TakeoffView {
 
@@ -24,7 +25,7 @@ public class TakeoffView {
 
     public void showDialog() {
         dialog.setModalityType(Dialog.ModalityType.APPLICATION_MODAL);
-        dialog.setTitle("Takeoff money");
+        dialog.setTitle(translate("Takeoff money"));
         dialog.pack();
         dialog.setResizable(false);
         dialog.setLocationRelativeTo(null);
@@ -43,7 +44,7 @@ public class TakeoffView {
         c.fill = GridBagConstraints.HORIZONTAL;
         c.anchor = GridBagConstraints.CENTER;
         c.insets = new Insets(4, 4, 4, 4);
-        dialog.getContentPane().add(new JLabel("Takeoff money"), c);
+        dialog.getContentPane().add(new JLabel(translate("Takeoff money")), c);
 
         c.gridx = 0;
         c.gridy = 1;
@@ -51,7 +52,7 @@ public class TakeoffView {
         c.fill = GridBagConstraints.NONE;
         c.anchor = GridBagConstraints.LAST_LINE_END;
         c.weightx = 0;
-        dialog.getContentPane().add(new JLabel("Value", SwingConstants.RIGHT), c);
+        dialog.getContentPane().add(new JLabel(translate("Value"), SwingConstants.RIGHT), c);
 
         c.gridx = 1;
         c.gridy = 1;
@@ -83,8 +84,8 @@ public class TakeoffView {
     private void createComponents() {
         this.dialog = new JDialog();
 
-        this.cancel = new JButton("Cancel");
+        this.cancel = new JButton(translate("Cancel"));
-        this.takeoff = new JButton("Takeoff");
+        this.takeoff = new JButton(translate("Takeoff"));
         this.value = new JFormattedTextField(StringDecoder.LOCAL_NUMBER_FORMAT);
 
         this.dialog.setContentPane(new JPanel(new GridBagLayout()));
@@ -92,7 +93,7 @@ public class TakeoffView {
 
     public double getAmount() {
         if (value.getText().isBlank()) {
-            showMessageDialog(null, "invalid amount", "currency must not be blank", ERROR_MESSAGE);
+            showMessageDialog(null, translate("Invalid amount"), translate("Currency must not be blank"), ERROR_MESSAGE);
             return 0;
         }
 

src/me/teridax/jcash/gui/transfer/TransferDialog.java

@@ -3,9 +3,11 @@ package me.teridax.jcash.gui.transfer;
 import me.teridax.jcash.Logging;
 import me.teridax.jcash.banking.accounts.Account;
 import me.teridax.jcash.banking.management.BankingManagementSystem;
+import me.teridax.jcash.lang.Translator;
 
 import static javax.swing.JOptionPane.ERROR_MESSAGE;
 import static javax.swing.JOptionPane.showMessageDialog;
+import static me.teridax.jcash.lang.Translator.translate;
 
 public class TransferDialog {
 
@@ -35,7 +37,7 @@ public class TransferDialog {
             transferView.dispose();
         } catch (IllegalArgumentException ex) {
             Logging.LOGGER.severe("Could not transfer: " + ex.getMessage());
-            showMessageDialog(null, "invalid account", "Could not transfer", ERROR_MESSAGE);
+            showMessageDialog(null, translate("Invalid account"), translate("Could not transfer"), ERROR_MESSAGE);
         }
     }
 }

src/me/teridax/jcash/gui/transfer/TransferView.java

@@ -8,6 +8,7 @@ import java.awt.*;
 
 import static javax.swing.JOptionPane.ERROR_MESSAGE;
 import static javax.swing.JOptionPane.showMessageDialog;
+import static me.teridax.jcash.lang.Translator.translate;
 
 public class TransferView {
 
@@ -25,7 +26,7 @@ public class TransferView {
 
     public void showDialog() {
         dialog.setModalityType(Dialog.ModalityType.APPLICATION_MODAL);
-        dialog.setTitle("Transfer money");
+        dialog.setTitle(translate("Transfer money"));
         dialog.pack();
         dialog.setSize(dialog.getWidth() * 2, dialog.getHeight());
         dialog.setResizable(false);
@@ -45,7 +46,7 @@ public class TransferView {
         c.fill = GridBagConstraints.HORIZONTAL;
         c.anchor = GridBagConstraints.CENTER;
         c.insets = new Insets(4, 4, 4, 4);
-        dialog.getContentPane().add(new JLabel("Transfer money"), c);
+        dialog.getContentPane().add(new JLabel(translate("Transfer money")), c);
 
         c.gridx = 0;
         c.gridy = 1;
@@ -53,7 +54,7 @@ public class TransferView {
         c.fill = GridBagConstraints.NONE;
         c.anchor = GridBagConstraints.LAST_LINE_END;
         c.weightx = 0;
-        dialog.getContentPane().add(new JLabel("BLZ", SwingConstants.RIGHT), c);
+        dialog.getContentPane().add(new JLabel(translate("BLZ"), SwingConstants.RIGHT), c);
 
         c.gridx = 1;
         c.gridy = 1;
@@ -67,7 +68,7 @@ public class TransferView {
         c.fill = GridBagConstraints.NONE;
         c.anchor = GridBagConstraints.LAST_LINE_END;
         c.weightx = 0;
-        dialog.getContentPane().add(new JLabel("IBAN", SwingConstants.RIGHT), c);
+        dialog.getContentPane().add(new JLabel(translate("IBAN"), SwingConstants.RIGHT), c);
 
         c.gridx = 3;
         c.gridy = 1;
@@ -81,7 +82,7 @@ public class TransferView {
         c.fill = GridBagConstraints.NONE;
         c.anchor = GridBagConstraints.LAST_LINE_END;
         c.weightx = 0;
-        dialog.getContentPane().add(new JLabel("Betrag", SwingConstants.RIGHT), c);
+        dialog.getContentPane().add(new JLabel(translate("Betrag"), SwingConstants.RIGHT), c);
 
         c.gridx = 1;
         c.gridy = 2;
@@ -106,8 +107,8 @@ public class TransferView {
     private void createComponents() {
         this.dialog = new JDialog();
 
-        this.cancel = new JButton("Cancel");
+        this.cancel = new JButton(translate("Cancel"));
-        this.transfer = new JButton("Transfer");
+        this.transfer = new JButton(translate("Transfer"));
         this.value = new JFormattedTextField(StringDecoder.LOCAL_NUMBER_FORMAT);
         this.iban = new JFormattedTextField();
         this.blz = new JFormattedTextField();
@@ -118,7 +119,7 @@ public class TransferView {
     public double getAmount() {
         if (value.getText().isBlank()) {
             Logging.LOGGER.severe("Amount is empty");
-            showMessageDialog(null, "invalid amount", "currency must not be blank", ERROR_MESSAGE);
+            showMessageDialog(null, translate("invalid amount"), translate("currency must not be blank"), ERROR_MESSAGE);
             return 0;
         }
 

src/me/teridax/jcash/lang/Locales.java

@@ -0,0 +1,56 @@
+package me.teridax.jcash.lang;
+
+import java.util.Locale;
+
+/**
+ * Class for storing static information about the locale used by the application instance at runtime.
+ */
+@SuppressWarnings("unused")
+public class Locales {
+
+    /**
+     * Locale string used to identify a certain locale
+     */
+    private static String defaultLocale = "en_EN";
+
+    /**
+     * Sets the default locale to use for the application instance.
+     * This will instruct the translator to use the default locale as well as
+     * Java swing components.
+     * @param language the locale to use for language
+     * @param country the locale to use for country
+     */
+    public static void setDefaultLocale(String language, String country) {
+        var locale = language + "_" + country;
+
+        if (Translator.setTranslationLocale(locale)) {
+            // apply locale to JVM
+            Locale.setDefault(new Locale(language, country));
+            defaultLocale = locale;
+        }
+    }
+
+    public static String getDefaultLocale() {
+        return defaultLocale;
+    }
+
+    /**
+     * Tries to automatically detect the default locale.
+     * This will prefer the users locale over the systems locale.
+     * If both fail, the JVMs default locale will be used.
+     */
+    public static void autodetectDefaultLocale() {
+        var country = System.getProperty("user.country");
+        var language = System.getProperty("user.language");
+
+        var jvmLocale = Locale.getDefault();
+
+        if (null == country)
+            country = jvmLocale.getCountry();
+
+        if (null == language)
+            language = jvmLocale.getLanguage();
+
+        setDefaultLocale(language, country);
+    }
+}

src/me/teridax/jcash/lang/Translator.java

@@ -0,0 +1,122 @@
+package me.teridax.jcash.lang;
+
+import me.teridax.jcash.Logging;
+
+import java.nio.charset.StandardCharsets;
+import java.util.*;
+import java.util.stream.Collectors;
+
+public final class Translator {
+
+    /**
+     * Precomputed index of the locale used to statically translate a phrase
+     */
+    private static int localeTranslationIndex = 0;
+
+    /**
+     * List of all supported locales in the format: language_country. Examples: en_EN, fr_FR
+     * The index inside the list is directly related to the index of the translation array inside the list translations.
+     */
+    private static final List<String> languages = new ArrayList<>();
+    /**
+     *  Mapping of a default english phrase of the code en_EN which is associated with  a list of possible translations.
+     *  Index 0 of the translation is equivalent to the key itself since locale 0 is always en_EN.
+     */
+    private static final Map<String, String[]> translations = new HashMap<>();
+
+    static {
+        // read language file and parse
+        try (var stream = Objects.requireNonNull(Translator.class.getResourceAsStream("languages.csv"))) {
+            var text = new String(stream.readAllBytes(), StandardCharsets.UTF_8);
+
+            // parse each line
+            text.lines().forEach(line -> {
+                // read header i.e. the locales identifier
+                if (languages.isEmpty()) {
+                    // split string into columns by comma and trim each column
+                    languages.addAll(Arrays.stream(line.split(",")).map(String::trim).collect(Collectors.toList()));
+
+                    // check if default locale is present
+                    if (!languages.contains("en_EN")) {
+                        Logging.LOGGER.severe("Missing default en_EN locale");
+                        throw new IllegalArgumentException("Missing en_EN locale");
+                    }
+
+                    Logging.LOGGER.info("Read locales: " + Arrays.deepToString(languages.toArray()));
+                    return;
+                }
+
+                var translation = Arrays.stream(line.split(",")).map(String::trim).toArray(String[]::new);
+
+                // check if all translations are present
+                // it may happen at a locale does not provide a translation
+                if (translation.length != languages.size())
+                    Logging.LOGGER.warning("invalid translations: " + translation.length + " " + languages.size());
+
+                translations.put(translation[0], translation);
+            });
+
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * Translates the given phrase into the corresponding phrase of the selected locale of the translator.
+     * If no translation is found or no locale is defined for the translator this function will return the given phrase.
+     * @param phrase the text to translate
+     * @return the translated phrase, or the phrase itself in case no translation can be found
+     */
+    public static String translate(String phrase) {
+        try {
+            return translations.get(phrase)[localeTranslationIndex];
+
+        } catch (ArrayIndexOutOfBoundsException e) {
+            Logging.LOGGER.severe("Locale does not exist with index: " + localeTranslationIndex);
+        } catch (NullPointerException e) {
+            Logging.LOGGER.severe("No translation found for phrase: " + phrase);
+        }
+        return phrase;
+    }
+
+    /**
+     * Returns an array of all available locales for this translator
+     * @return an array of all available locales for this translator
+     */
+    public static String[] availableLocales() {
+        return languages.toArray(String[]::new);
+    }
+
+    /**
+     * Map the given locale string to an index indicating which array location to choose when fetching a result from
+     * the translation map.
+     * @param locale the locale string
+     * @return a matching index of the locale
+     * @throws IllegalArgumentException if the given locale is not part of the available locales
+     */
+    private static int mapLocaleToIndex(String locale) throws IllegalArgumentException {
+        for (int i = 0; i < languages.size(); i++) {
+            if (languages.get(i).equals(locale)) {
+                return i;
+            }
+        }
+
+        throw new IllegalArgumentException("Locale does not exist: " + locale);
+    }
+
+    /**
+     * Sets the default locale to use when translating.
+     * The locale must have the format language_COUNTRY like en_EN
+     * @param locale the locale to use when translating
+     * @return if the specified locale can be used by the translator
+     */
+    public static boolean setTranslationLocale(String locale) {
+        try {
+            localeTranslationIndex = Translator.mapLocaleToIndex(locale);
+            return true;
+        } catch (IllegalArgumentException ex) {
+            Logging.LOGGER.severe("unable to set locale for translation: " + locale + " because: " + ex.getMessage());
+            return false;
+        }
+    }
+}

src/me/teridax/jcash/lang/languages.csv

@@ -0,0 +1,48 @@
+en_EN,de_DE,es_ES,fr_FR,zh_Hans
+Bank,Bank,Banco,Banque,银行
+BLZ,BLZ,BLZ,CODE BANCAIRE,分类代码
+PIN,PIN,PIN,CODE PIN,密码
+Balance,Kontostand,Saldo,Solde du compte,账户余额
+Account type,Kontoart,Tipo de cuenta,Type de compte,账户类型
+Interest,Zins,Interés,Intérêt,利息
+Overdraft,Überziehungsbetrag,Importe del descubierto,Montant du découvert,透支金额
+Customer number,Kundennummer,Número de cliente,Numéro de client,客户编号
+Name,Name,Nombre,Nom,客户姓名
+Name,Vorname,Nombre,Prénom,姓名
+Street,Straße,Calle,Rue,街道
+PLZ,PLZ,PLZ,NPA,邮政编码
+City,Ort,Ubicación,Ville,城市
+Password,Passwort,contraseña,Mot de passe,密码
+Login,Anmelden,Inicio de sesión,S'inscrire,登录
+Current account,Girokonto,Cuenta corriente,Compte courant,活期账户
+Savings account,Sparkonto,Cuenta de ahorro,Compte d'épargne,储蓄账户
+Address,Adresse,Dirección,Adresse,地址
+Logout,Abmelden,desconectarse,Se désinscrire,退出登录
+Transfer,Überweisen,transferencia,Virement bancaire,转账
+Deposit,Einzahlen,depósito,Dépôt,存款
+Take off,Abheben,despegar,Retrait,取款
+Value,Betrag,Importe,Montant,金额
+Cancel,Abbrechen,Cancelar,Annuler,取消
+Load database,Datenbank auswählen,Seleccionar base de datos,Sélectionner la base de données,选择数据库
+Invalid account,Ungültiges Benutzerkonto,Cuenta de usuario no válida,Compte utilisateur non valide,用户账户无效
+Could not transfer,Überweiung fehlgeschlagen,Transferencia fallida,Échec du transfert,转账失败
+Transfer,Überweisen,Transferencia,Transfert,转帐
+invalid amount,Ungültiger Betrag,Importe no válido,Montant non valide,金额无效
+currency must not be blank,Betrag darf nicht leer sein,El importe no debe estar vacío,Le montant ne doit pas être vide,金额不能为空
+Transfer money,Geld überweisen,Transferencia de dinero,Transférer de l'argent,汇款
+Could not take off money,Geld konnte nicht abgehoben werden,No se ha podido retirar dinero,L'argent n'a pas pu être retiré,无法取款
+Takeoff money,Geld abheben,Retirar dinero,Retirer de l'argent,取款
+Takeoff,Abheben,Retirar,Retrait,取款
+Currency must not be blank,Betrag darf nicht leer sein,El importe no debe estar vacío,Le montant ne doit pas être vide,金额不能为空
+Cashmachine,Bankautomat,CAJERO,Distributeur automatique de billets,ATM
+Invalid IBAN,Ungültige IBAN,IBAN no válido,IBAN non valide,无效的IBAN
+Faulty login attempt,Ungültiger Authentifizierungsverzuch,Solicitud de autenticación no válida,Demande d'authentification non valide,验证请求无效
+Invalid PIN,Ungültiger PIN,PIN no válido,Code PIN non valide,密码无效
+Invalid login credentials,Ungültiges Passwort oder Nutzername,Contraseña o nombre de usuario no válidos,Mot de passe ou nom d'utilisateur non valide,密码或用户名无效
+Deposit money,Geld einzahlen,Depositar dinero,Dépôt d'argent,存款金额
+Interest rate,Zinsbetrag,Importe de los intereses,Montant des intérêts,利息金额
+Name/Family-name,Vorname/Name,Nombre y apellidos,Prénom/nom,名/姓
+Address,Adresse,Dirección,Adresse,地址
+Account,Konto,Cuenta,Compte,账户
+Closing JCash,JCash wird geschlossen,JCash está cerrado,JCash est fermé,JCash 已关闭
+you're logged out,Du bist abgemeldet,Ha cerrado la sesión,Tu es déconnecté,您已注销