sonarqube java，sonar，圈复杂度

Question

有谁能帮我把下面的方法的复杂度降低到10。。此外，还考虑到如果允许，则不会嵌套，因为这也会导致声纳问题。 这对我会有很大帮助

private void processIntransitFile(String fileName) {
        if (StringUtils.isNotBlank(fileName))
            return;

        // read Intransit folder and do the processing on these files
        try (BufferedReader bufferedReader = new BufferedReader(new FileReader(intransitDir + fileName))) {
            TokenRangeDTO tokenRangeDTO = new TokenRangeDTO();
            int count = 0;
            String header = "";
            String next;
            String line = bufferedReader.readLine();
            LinkedHashSet<String> tokenRanges = new LinkedHashSet<>();
            int trCount = 0;
            boolean first = true;
            boolean last = line == null;
            while (!last) {
                last = (next = bufferedReader.readLine()) == null;
                if (!first && !last) {
                    tokenRanges.add(line);
                }
                // read first line of the file
                else if (first && line.startsWith(H)) {
                    header = line;
                    first = false;
                } else if (first && !line.startsWith(H)) {
                    tokenRangeDTO.setValidationMessage(HEADER_MISSING);
                    first = false;
                }
                // read last line of the file
                else if (last && line.startsWith(T)) {
                    trCount = getTrailerCount(tokenRangeDTO, line, trCount);
                } else if (last && !line.startsWith(T)) {
                    tokenRangeDTO.setValidationMessage(TRAILOR_MISSING);
                }

                line = next;
                count++;
            }
            processInputFile(fileName, tokenRangeDTO, count, header, tokenRanges, trCount);
        } catch (IOException e) {
            LOGGER.error(IO_EXCEPTION, e);
        } catch (Exception e) {
            LOGGER.error("Some exception has occured", e);
        } finally {
            try {
                FileUtils.deleteQuietly(new File(intransitDir + fileName));
            } catch (Exception ex) {
                LOGGER.error(STREAM_FAILURE, ex);
            }
        }
    }

有谁能帮我把下面的方法的复杂度降低到10。。此外，还考虑到如果允许，则不会嵌套，因为这也会导致声纳问题。 这对我会有很大帮助