static List<String> tokenize(String cron) throws IllegalArgumentException {
        StringTokenizer tokenize = new StringTokenizer(cron);
        List<String> result = new ArrayList<String>();
        while (tokenize.hasMoreTokens()) {
            result.add(tokenize.nextToken());
        }
        if (result.size() != NUMBER_TOKENS) {
            throw new IllegalArgumentException("Not a valid cron entry - wrong number of tokens(" + result.size()
                    + "): " + cron);
        }
        return result;
    }
@Test
    public void testTokenize() {
        String test = "*/5 * * * *";
        List<String> list = CronParser.tokenize(test);
        assertEquals(list.size(), 5);

        test = "*/5 * * * * *";
        try {
            list = CronParser.tokenize(test);
            fail("Should have throw an exception");
        } catch (Throwable e) {
        }

        test = "*/5 * * * *";
        try {
            list = CronParser.tokenize(test);
            fail("Should have throw an exception");
        } catch (Throwable e) {
        }

        test = "0 1 2 3 4";
        list = CronParser.tokenize(test);
        assertEquals(list.size(), 5);

        assertEquals(list.get(0), "0");
        assertEquals(list.get(1), "1");
        assertEquals(list.get(2), "2");
        assertEquals(list.get(3), "3");
        assertEquals(list.get(4), "4");
    }