Method isEmpty

corpus/java/training/guava/io/CharSource.java:334–348

Returns whether the source has zero chars. The default implementation returns true if #lengthIfKnown returns zero, falling back to opening a stream and checking for EOF if the length is not known. Note that, in cases where lengthIfKnown returns zero, it is possible that ch

()

   * @since 15.0
   */
  public boolean isEmpty() throws IOException {
    Optional<Long> lengthIfKnown = lengthIfKnown();
    if (lengthIfKnown.isPresent() && lengthIfKnown.get() == 0L) {
      return true;
    }
    Closer closer = Closer.create();
    try {
      Reader reader = closer.register(openStream());
      return reader.read() == -1;
    } catch (Throwable e) {
      throw closer.rethrow(e);
    } finally {
      closer.close();
    }
  }

  /**
   * Concatenates multiple {@link CharSource} instances into a single source. Streams returned from