Method isEmpty

guava/src/com/google/common/io/CharSource.java:416–430

Returns whether the source has zero chars. The default implementation first checks {@link #lengthIfKnown}, returning true if it's known to be zero and false if it's known to be non-zero. If the length is not known, it falls back to opening a stream and checking for EOF. <p>Note that, in cases where

()

   * @since 15.0
   */
  public boolean isEmpty() throws IOException {
    Optional<Long> lengthIfKnown = lengthIfKnown();
    if (lengthIfKnown.isPresent()) {
      return lengthIfKnown.get() == 0L;
    }
    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