public class Basis {

  public static String insertString(String message, String title, String vorgabe) {
     TextInputDialog dialog = new TextInputDialog(vorgabe);
     dialog.setTitle(title);
     dialog.setContentText(message);
     dialog.setHeaderText(title);
     dialog.setResizable(true);
     java.util.Optional<String> result = dialog.showAndWait();

     if (result.isPresent()) {
        return (String)result.get();
     }
     else {
       return null; 
    }
  } 
      public static void errorBox( String message, String title) {
         Dialog alert = new Alert(Alert.AlertType.ERROR,message);
         alert.setTitle(title);
         alert.setHeaderText(title);
         alert.setResizable(true);
         alert.show();
//        a.setContentText(content);
      } // ErrorBox

      public static double getDoubleNumber(String str_zahl) {
	try {
		double zahl = Double.parseDouble(str_zahl);
		return zahl;
	}
	catch (NumberFormatException e) {
		return Double.NaN;
	}  // try
      }  // getDoubleNumber      


    public static Integer getIntegerNumber(String str_zahl) {
	try {
                int zahl = Integer.parseInt(str_zahl);
		return zahl;
	}
	catch (NumberFormatException e) {
		return null;
	}  // try
      }  // getIntegerNumber      
}