code: private String getProperty(String variable, EvaluationContext context, boolean ignoreWarnings, boolean useEnvironment) throws ConfigEvaluatorException {
          return stringUtils.convertToString(getPropertyObject(variable, context, ignoreWarnings, useEnvironment));
      }
docs: Returns the value of the variable as a string, or null if the property
  does not exist.
  
  @param variable the variable name