public boolean tryMergePartFiles()

in hugegraph-hubble/hubble-be/src/main/java/org/apache/hugegraph/service/load/FileMappingService.java [177:238]
58 lines of code
10 McCabe index (conditional complexity)

    public boolean tryMergePartFiles(String dirPath, int total) {
        File dir = new File(dirPath);
        File[] partFiles = dir.listFiles();
        if (partFiles == null) {
            throw new InternalException("The part files can't be null");
        }
        if (partFiles.length != total) {
            return false;
        }

        File newFile = new File(dir.getPath() + ".all");
        File destFile = new File(dir.getPath());
        if (partFiles.length == 1) {
            try {
                // Rename file to dest file
                FileUtils.moveFile(partFiles[0], newFile);
            } catch (IOException e) {
                log.error("Failed to rename file from {} to {}",
                          partFiles[0], newFile, e);
                throw new InternalException("load.upload.move-file.failed", e);
            }
        } else {
            Arrays.sort(partFiles, (o1, o2) -> {
                String file1Idx = StringUtils.substringAfterLast(o1.getName(),
                                                                 "-");
                String file2Idx = StringUtils.substringAfterLast(o2.getName(),
                                                                 "-");
                Integer idx1 = Integer.valueOf(file1Idx);
                Integer idx2 = Integer.valueOf(file2Idx);
                return idx1.compareTo(idx2);
            });
            try (OutputStream os = new FileOutputStream(newFile, true)) {
                for (int i = 0; i < partFiles.length; i++) {
                    File partFile = partFiles[i];
                    try (InputStream is = new FileInputStream(partFile)) {
                        IOUtils.copy(is, os);
                    } catch (IOException e) {
                        log.error("Failed to copy file stream from {} to {}",
                                  partFile, newFile, e);
                        throw new InternalException(
                                  "load.upload.merge-file.failed", e);
                    }
                }
            } catch (IOException e) {
                log.error("Failed to copy all file-parts stream to {}",
                          newFile, e);
                throw new InternalException("load.upload.merge-file.failed", e);
            }
        }
        // Delete origin directory
        try {
            FileUtils.forceDelete(dir);
        } catch (IOException e) {
            log.error("Failed to force delete file {}", dir, e);
            throw new InternalException("load.upload.delete-temp-dir.failed", e);
        }
        // Rename file to dest file
        if (!newFile.renameTo(destFile)) {
            throw new InternalException("load.upload.rename-file.failed");
        }
        return true;
    }