code: public void copySingleFile(File asset) {
          try {
              if ( !asset.isDirectory() ) {
                  String targetPath = config.getDestinationFolder().getCanonicalPath() + File.separatorChar + assetSubPath(asset);
                  LOGGER.info("Copying single asset file to [{}]", targetPath);
                  copyFile(asset, new File(targetPath));
              } else {
                  LOGGER.info("Skip copying single asset file [{}]. Is a directory.", asset.getPath());
              }
          } catch (IOException io) {
              LOGGER.error("Failed to copy the asset file.", io);
          }
      }
docs: Copy one asset file at a time.
  
  @param asset The asset file to copy