public static String getSuffixName(String dirPath, String filePath) {
        if (!FeConstants.runningUnitTest) {
            Preconditions.checkArgument(filePath.startsWith(dirPath),
                    "dirPath " + dirPath + " should be prefix of filePath " + filePath);
        }

        //we had checked the startsWith, so just get substring
        String name = filePath.substring(dirPath.length());
        if (name.startsWith("/")) {
            name = name.substring(1);
        }
        return name;
    }
@Test
    public void testGetSuffixName() {
        Assert.assertEquals("file", getSuffixName("/path/", "/path/file"));
        Assert.assertEquals("file", getSuffixName("/path", "/path/file"));
        Assert.assertEquals("file", getSuffixName("/dt=(a)/", "/dt=(a)/file"));
    }