@Override
        public int estimateLength() {
            if (mTimeZone != null) {
                return Math.max(mStandard.length(), mDaylight.length());
            }
            else if (mStyle == TimeZone.SHORT) {
                return 4;
            }
            else {
                return 40;
            }
        }
Returns an estimate for the maximum length date that this date
formatter will produce. The actual formatted length will almost always
be less than or equal to this amount.
@return an estimate of the maximum length
xmppserver/src/main/java/org/jivesoftware/util/FastDateFormat.java