private static void visitDayOfWeekToken(int repetitions, JQueryDateTimePatternBuilder builder) {
        switch (repetitions) {
            case 1:
            case 2:
            case 3:
                builder.appendDayNameShort();
                break;
            default: // 4+
                builder.appendDayNameLong();
                break;
        }
    }
Day of week token 'E' and 'EE', 'EEE', and 'EEEE'. Four and more 'E' are
interpreted as a long day name, everything else as a short day name.
primefaces/src/main/java/org/primefaces/convert/CombinedDateTimePatternTokenVisitor.java