docs: protected Integer parseIntString(String string, boolean abortOnError, int def)
          throws TransformationOperationException {
          Integer integer = def;
          if (string == null) {
              logger.debug("Given string is empty so the default value is taken.");
          }
          try {
              integer = Integer.parseInt(string);
          } catch (NumberFormatException e) {
              StringBuilder builder = new StringBuilder();
              builder.append("The string ").append(string).append(" is not a number. ");
              if (abortOnError) {
                  builder.append("The step will be skipped.");
              } else {
                  builder.append(def).append(" will be taken instead.");
              }
  
              logger.warn(builder.toString());
              if (abortOnError) {
                  throw new TransformationOperationException(builder.toString());
              }
          }
          return integer;
      }