public static RPCHook getAclRPCHook(String fileName) {
        JSONObject yamlDataObject;
        try {
            yamlDataObject = AclUtils.getYamlDataObject(fileName,
                JSONObject.class);
        } catch (Exception e) {
            log.error("Convert yaml file to data object error, ", e);
            return null;
        }
        return buildRpcHook(yamlDataObject);
    }
@Test
    public void getAclRPCHookTest() throws IOException {
        try (InputStream is = AclUtilsTest.class.getClassLoader().getResourceAsStream("conf/plain_acl_incomplete.yml")) {
            RPCHook incompleteContRPCHook = AclUtils.getAclRPCHook(is);
            Assert.assertNull(incompleteContRPCHook);
        }
    }