public int getItemCount() {
        return this.values.getRowCount();
    }

    /**
     * Returns the number of items in a series.  This is the same value
     * that is returned by {@link #getItemCount()} since all series
     * share the same x-values (time periods).
     *
     * @param series  the series (zero-based index, ignored).
     *
     * @return The number of items within the series.
     */
    public int getItemCount(int series) {
        return getItemCount();