code: void initFromDir() {
      for (File file : this.logDir.listFiles()) {
        if (!file.isDirectory() &&
            file.getName().matches("transaction\\.\\d+_\\d+")) {
          // Appends the file with valid name to log file list.
          this.logFiles.add(file);
        }
      }
      if (!this.logFiles.isEmpty()) {
        // Sorts the file by the zxid order.
        Collections.sort(this.logFiles);
      }
    }
docs: Initialize from the log directory.