Merge pull request #191 from doubleSlashde/bugfix/PTBAS-737_consistentLanguage_2

using consistent english language now. keeping dates in system locale

Author: Death111

src/main/java/de/doubleslash/keeptime/App.java

@@ -21,6 +21,7 @@
 import java.io.StringWriter;
 import java.time.LocalDate;
 import java.util.List;
+import java.util.Locale;
 import java.util.Optional;
 import java.util.stream.Collectors;
 
@@ -84,6 +85,9 @@ public class App extends Application {
    @Override
    public void init() throws Exception {
       LOG.info("Starting KeepTime.");
+
+      setLocaleToEnglish();
+
       final DefaultExceptionHandler defaultExceptionHandler = new DefaultExceptionHandler();
       defaultExceptionHandler.register();
 
@@ -102,6 +106,22 @@ public void init() throws Exception {
       model.setSpringContext(springContext);
    }
 
+   private void setLocaleToEnglish() {
+      final Locale systemDefaultLocale = Locale.getDefault();
+      final Locale wantedApplicationLocale = Locale.ENGLISH;
+
+      if (systemDefaultLocale.getLanguage().equals(wantedApplicationLocale.getLanguage())) {
+         LOG.debug("Application locale already is '{}'. Nothing to do.", wantedApplicationLocale);
+         return;
+      }
+
+      LOG.info("Setting application locale to '{}', was '{}'.", wantedApplicationLocale, systemDefaultLocale);
+      Locale.setDefault(wantedApplicationLocale);
+      Locale.setDefault(Locale.Category.DISPLAY, wantedApplicationLocale);
+      // keep system locale for format conversions (date, currency, numbers)
+      Locale.setDefault(Locale.Category.FORMAT, systemDefaultLocale);
+   }
+
    @Override
    public void start(final Stage primaryStage) {
       LOG.info("Initialising the UI");
@@ -117,12 +137,13 @@ public void start(final Stage primaryStage) {
       }
    }
 
-   public static void showErrorDialogAndWait(String title, String header, String content, final Exception e, Window window) {
+   public static void showErrorDialogAndWait(String title, String header, String content, final Exception e,
+         Window window) {
       final Alert alert = new Alert(AlertType.ERROR);
       alert.setTitle(title);
       alert.setHeaderText(header);
       alert.setContentText(content);
-      if(window != null) {
+      if (window != null) {
          alert.initOwner(window);
       }
       final StringWriter sw = new StringWriter();