code: public static String getVariablesMapExpression(Collection variables) {
          StringBuilder variablesMap = new StringBuilder("new  " + PropertiesMap.class.getName() + "()");
          for (Object variable : variables) {
              JRVariable jrvar = (JRVariable) variable;
              String varname = jrvar.getName();
              variablesMap.append(".with(\"").append(varname).append("\",$V{").append(varname).append("})");
          }
          return variablesMap.toString();
      }
docs: Collection of JRVariable
  
  @param variables
  @return