class LogIndexer {

    public Log getLog(long logIndex) {
        if (logIndex < 0 || logIndex > curIndex()) {
            return Log.createBy(logIndex, "", "Log not exists");
        }

        String val = get(logIndex);
        int separator = val.indexOf(keySeparator);
        String txId = val.substring(0, separator);
        int indexOfReceipt = Integer.parseInt(val.substring(separator + 1));
        String log = receiptStore.get(txId).getLog().get(indexOfReceipt);

        return Log.createBy(logIndex, txId, log);
    }

    public  LogIndexer(LogStore logStore, ReceiptStore receiptStore);

}