public static String createTempFileFromResource()

in runtime/java/treelite4j/src/main/java/ml/dmlc/treelite4j/NativeLibLoader.java [74:127]
39 lines of code
10 McCabe index (conditional complexity)

  public static String createTempFileFromResource(String path) throws
          IOException, IllegalArgumentException {
    // Obtain filename from path
    if (!path.startsWith("/")) {
      throw new IllegalArgumentException("The path has to be absolute (start with '/').");
    }

    String[] parts = path.split("/");
    String filename = (parts.length > 1) ? parts[parts.length - 1] : null;

    // Split filename to prexif and suffix (extension)
    String prefix = "";
    String suffix = null;
    if (filename != null) {
      parts = filename.split("\\.", 2);
      prefix = parts[0];
      suffix = (parts.length > 1) ? "." + parts[parts.length - 1] : null; // Thanks, davs! :-)
    }

    // Check if the filename is okay
    if (filename == null || prefix.length() < 3) {
      throw new IllegalArgumentException("The filename has to be at least 3 characters long.");
    }
    // Prepare temporary file
    File temp = File.createTempFile(prefix, suffix);
    temp.deleteOnExit();

    if (!temp.exists()) {
      throw new FileNotFoundException("File " + temp.getAbsolutePath() + " does not exist.");
    }

    // Prepare buffer for data copying
    byte[] buffer = new byte[1024];
    int readBytes;

    // Open and check input stream
    InputStream is = NativeLibLoader.class.getResourceAsStream(path);
    if (is == null) {
      throw new FileNotFoundException("File " + path + " was not found inside JAR.");
    }

    // Open output stream and copy data between source file in JAR and the temporary file
    OutputStream os = new FileOutputStream(temp);
    try {
      while ((readBytes = is.read(buffer)) != -1) {
        os.write(buffer, 0, readBytes);
      }
    } finally {
      // If read/write fails, close streams safely before throwing an exception
      os.close();
      is.close();
    }
    return temp.getAbsolutePath();
  }