public XYSeriesLabelGenerator getLegendItemLabelGenerator() {
        return this.legendItemLabelGenerator;
    }

    /**
     * Sets the legend item label generator and sends a
     * {@link RendererChangeEvent} to all registered listeners.
     *
     * @param generator  the generator (<code>null</code> not permitted).
     *
     * @see #getLegendItemLabelGenerator()
     */
    public void setLegendItemLabelGenerator(XYSeriesLabelGenerator generator) {
        if (generator == null) {
            throw new IllegalArgumentException("Null 'generator' argument.");
        }
        this.legendItemLabelGenerator = generator;
        fireChangeEvent();
    }

    /**
     * Returns the legend item tool tip generator.
     *
     * @return The tool tip generator (possibly <code>null</code>).
     *
     * @see #setLegendItemToolTipGenerator(XYSeriesLabelGenerator)
     */
    public XYSeriesLabelGenerator getLegendItemToolTipGenerator() {
        return this.legendItemToolTipGenerator;
    }

    /**
     * Sets the legend item tool tip generator and sends a
     * {@link RendererChangeEvent} to all registered listeners.
     *
     * @param generator  the generator (<code>null</code> permitted).
     *
     * @see #getLegendItemToolTipGenerator()
     */
    public void setLegendItemToolTipGenerator(
            XYSeriesLabelGenerator generator) {
        this.legendItemToolTipGenerator = generator;
        fireChangeEvent();
    }

    /**
     * Returns the legend item URL generator.
     *
     * @return The URL generator (possibly <code>null</code>).
     *
     * @see #setLegendItemURLGenerator(XYSeriesLabelGenerator)
     */
    public XYSeriesLabelGenerator getLegendItemURLGenerator() {
        return this.legendItemURLGenerator;
    }

    /**
     * Sets the legend item URL generator and sends a
     * {@link RendererChangeEvent} to all registered listeners.
     *
     * @param generator  the generator (<code>null</code> permitted).
     *
     * @see #getLegendItemURLGenerator()
     */
    public void setLegendItemURLGenerator(XYSeriesLabelGenerator generator) {
        this.legendItemURLGenerator = generator;
        fireChangeEvent();