public long copyTo(CharSink sink) throws IOException {
    checkNotNull(sink);

    Closer closer = Closer.create();
    try {
      Reader reader = closer.register(openStream());
      Writer writer = closer.register(sink.openStream());
      return CharStreams.copy(reader, writer);
    } catch (Throwable e) {
      throw closer.rethrow(e);
    } finally {
      closer.close();
    }
  }

  /**

   */
  public abstract InputStream openStream() throws IOException;

  /**
   * Opens a new buffered {@link InputStream} for reading from this source. The returned stream is
   * not required to be a {@link BufferedInputStream} in order to allow implementations to simply
   * delegate to {@link #openStream()} when the stream returned by that method does not benefit from

    // Slice it starting at offset 10.
    ByteSource slice = source.slice(10, 5);

    // Open a stream to the slice.
    InputStream in = slice.openStream();

    // Append 10 more bytes to the source.
    source.append(newPreFilledByteArray(5, 10));

    // The stream reports no bytes... importantly, it doesn't read the byte at index 5 when it

    // Slice it starting at offset 10.
    ByteSource slice = source.slice(10, 5);

    // Open a stream to the slice.
    InputStream in = slice.openStream();

    // Append 10 more bytes to the source.
    source.append(newPreFilledByteArray(5, 10));

    // The stream reports no bytes... importantly, it doesn't read the byte at index 5 when it

    // read the first 8 chars manually, since there's no equivalent to ByteSource.slice
    // TODO(cgdecker): Add CharSource.slice?
    StringBuilder builder = new StringBuilder();
    Reader reader = concatenated.openStream(); // no need to worry about closing
    for (int i = 0; i < 8; i++) {
      builder.append((char) reader.read());
    }
    assertEquals(expected, builder.toString());
  }

    // read the first 8 chars manually, since there's no equivalent to ByteSource.slice
    // TODO(cgdecker): Add CharSource.slice?
    StringBuilder builder = new StringBuilder();
    Reader reader = concatenated.openStream(); // no need to worry about closing
    for (int i = 0; i < 8; i++) {
      builder.append((char) reader.read());
    }
    assertEquals(expected, builder.toString());
  }

            this.src = src;
        }

        @Override
        public Path getPath() {
            return path;
        }

        @Override
        public InputStream openStream() throws IOException {
            return Files.newInputStream(src);
        }

        @Override
        public String getLocation() {
            return src.toString();
        }

            this.zipUrl = zipUrl;
            this.prefix = prefix;
        }

        private void loadFromZip(final URL zipUrl) {
            final ZipInputStream zis = new ZipInputStream(URLUtil.openStream(zipUrl));
            try {
                ZipEntry entry = null;
                while ((entry = ZipInputStreamUtil.getNextEntry(zis)) != null) {
                    entryNames.add(entry.getName());

    public static InputStream getResourceAsStream(final String path, final String extension) {
        assertArgumentNotEmpty("path", path);

        final URL url = getResource(path, extension);
        return URLUtil.openStream(url);
    }

    /**
     * コンテキストクラスローダからリソースを検索してストリームとして返します。 リソースが見つからなかった場合は<code>null</code>
     * を返します。
     *
     * @param path
     *            リソースのパス。{@literal null}や空文字列であってはいけません

      ByteSource
  {

    private final File file;

    private FileByteSource(File file) {
      this.file = checkNotNull(file);
    }

    @Override
    public FileInputStream openStream() throws IOException {
      return new FileInputStream(file);
    }

    @Override
    public Optional<Long> sizeIfKnown() {
      if (file.isFile()) {
        return Optional.of(file.length());