checkArgument(maximumWeight >= 0, "maximum weight must not be negative");
    this.maximumWeight = maximumWeight;
    return this;
  }

  /**
   * Specifies the weigher to use in determining the weight of entries. Entry weight is taken into
   * consideration by {@link #maximumWeight(long)} when determining which entries to evict, and use

      successor(this, right, succ());
      height = max(2, height);
      distinctElements++;
      totalCount += count;
      return this;
    }

    @CanIgnoreReturnValue
    private AvlNode<E> addLeftChild(@ParametricNullness E e, int count) {
      left = new AvlNode<>(e, count);
      successor(pred(), left, this);
      height = max(2, height);
      distinctElements++;
      totalCount += count;

                final int width = reader.getWidth(0);
                final int height = reader.getHeight(0);
                if (width <= 0 || height <= 0) {
                    return Result.NO_IMAGE;
                }
                if (!fessConfig.validateThumbnailSize(width, height)) {
                    return Result.INVALID_SIZE;
                }

        }
    }

    private void assertImageSize(File file, int width, int height) throws IOException {
        BufferedImage img = ImageIO.read(file);
        logger.debug("width: {}, height: {}", img.getWidth(), img.getHeight());
        assertEquals("Image Width", width, img.getWidth());
        assertEquals("Image Height", height, img.getHeight());
    }

    java.math.BigDecimal getThumbnailHtmlImageMaxAspectRatioAsDecimal();

    default boolean validateThumbnailSize(final int width, final int height) {
        if (width <= 0 || height <= 0 || width < getThumbnailHtmlImageMinWidthAsInteger().intValue()
                || height < getThumbnailHtmlImageMinHeightAsInteger().intValue()) {
            return false;
        }

    return new ConstantWeigher(constant);
  }

  /** Returns a {@link Weigher} that uses the integer key as the weight. */
  static Weigher<Integer, Object> intKeyWeigher() {
    return new IntKeyWeigher();
  }

  /** Returns a {@link Weigher} that uses the integer value as the weight. */
  static Weigher<Object, Integer> intValueWeigher() {
    return new IntValueWeigher();
  }

            "five", 5,
            "six", 6,
            "seven", 7,
            "eight", 8),
        "one",
        1,
        "two",
        2,
        "three",
        3,
        "four",
        4,
        "five",
        5,
        "six",
        6,
        "seven",
        7,
        "eight",
        8);
    assertMapEquals(
        ImmutableBiMap.of(
            "one", 1,

            "one", 1,
            "two", 2,
            "three", 3,
            "four", 4,
            "five", 5,
            "six", 6,
            "seven", 7,
            "eight", 8),
        "eight",
        8,
        "five",
        5,
        "four",
        4,
        "one",
        1,
        "seven",
        7,
        "six",
        6,
        "three",

  @Override
  public void write(char[] cbuf, int off, int len) throws IOException {
    checkNotClosed();
    // It turns out that creating a new String is usually as fast, or faster
    // than wrapping cbuf in a light-weight CharSequence.
    target.append(new String(cbuf, off, len));
  }

  /*
   * Override a few functions for performance reasons to avoid creating unnecessary strings.
   */

  @Override

                final Integer height = getAttributeAsInteger(attributes, "height");
                final Integer width = getAttributeAsInteger(attributes, "width");
                if (!fessConfig.isThumbnailHtmlImageUrl(thumbnailUrl)) {
                    continue;
                }
                if (height != null && width != null) {
                    try {