public XYToolTipGenerator getToolTipGenerator(int series, int item) {
        // return the generator for ALL series, if there is one...
        if (this.toolTipGenerator != null) {
            return this.toolTipGenerator;
        }

        // otherwise look up the generator table
        XYToolTipGenerator generator
                = (XYToolTipGenerator) this.toolTipGeneratorList.get(series);
        if (generator == null) {
            generator = this.baseToolTipGenerator;
        }
        return generator;