code: public String getExpressionString(String name, Object permission) {
  		String expression = properties.getProperty(CONFIG_EXPRESSION_PREFIX + name + "." + permission);
  
  		//Get generic permit
  		if (expression == null) {
  			expression = properties.getProperty(CONFIG_EXPRESSION_PREFIX + name);
  		}
  
  		//Get parent permit
  		if (expression == null && StringUtils.contains(name, ".")) {
  			String parent = StringUtils.substringBeforeLast(name, ".");
  			expression = getExpressionString(parent, permission);
  		}
  
  		LOG.debug("Get Expression String: [{}] for name: [{}] permission: [{}]", expression, name, permission);
  		return expression;
  	}
docs: Find the expression string recursively from the config file
  
  @param name
  @param permission
  @return