public String convert(Object o) {
        StringBuilder buf = new StringBuilder();
        Converter<Object> p = headTokenConverter;
        while (p != null) {
            buf.append(p.convert(o));
            p = p.getNext();
        }
        return buf.toString();
    }
@Test
    public void convertMultipleDates() {
        Calendar cal = Calendar.getInstance();
        cal.set(2003, 4, 20, 17, 55);
        FileNamePattern fnp = new FileNamePattern("foo-%d{yyyy.MM, aux}/%d{yyyy.MM.dd}.txt", context);
        assertEquals("foo-2003.05/2003.05.20.txt", fnp.convert(cal.getTime()));
    }