public String doLayout(ILoggingEvent event) {
        if (!isStarted()) {
            return CoreConstants.EMPTY_STRING;
        }
        return writeLoopOnConverters(event);
    }
@Test
    public void testWithLettersComingFromLog4j() {
        // Letters: p = level and c = logger
        pl.setPattern("%d %p [%t] %c{30} - %m%n");
        pl.start();
        String val = pl.doLayout(getEventObject());
        // 2006-02-01 22:38:06,212 INFO [main] c.q.l.pattern.ConverterTest - Some
        // message
        String regex = ClassicTestConstants.ISO_REGEX + " INFO " + MAIN_REGEX
                + " c.q.l.c.pattern.ConverterTest - Some message\\s*";
        assertTrue(val.matches(regex));
    }