class DefaultMessageStore implements MessageStore {

    public MessageExt lookMessageByOffset(long commitLogOffset) {
        SelectMappedBufferResult sbr = this.commitLog.getMessage(commitLogOffset, 4);
        if (null != sbr) {
            try {
                // 1 TOTALSIZE
                int size = sbr.getByteBuffer().getInt();
                return lookMessageByOffset(commitLogOffset, size);
            } finally {
                sbr.release();
            }
        }

        return null;
    }

    public  DefaultMessageStore(final MessageStoreConfig messageStoreConfig, final BrokerStatsManager brokerStatsManager,
        final MessageArrivingListener messageArrivingListener, final BrokerConfig brokerConfig);

}