*
     * @param series  the series (zero-based index, ignored).
     *
     * @return The number of items within the series.
     */
    public int getItemCount(int series) {
        return getItemCount();
    }
    
    /**
     * Returns the number of series in the dataset.
     *
     * @return The series count.
     */
    public int getSeriesCount() {
        return this.values.getColumnCount();
    }

    /**
     * Returns the key for a series.
     *
     * @param series  the series (zero-based index).
     *
     * @return The key for the series.
     */
    public Comparable getSeriesKey(int series) {
        return this.values.getColumnKey(series);
    }
    
    /**
     * Returns the x-value for an item within a series.  The x-values may or 
     * may not be returned in ascending order, that is up to the class 
     * implementing the interface.
     *
     * @param series  the series (zero-based index).
     * @param item  the item (zero-based index).
     *
     * @return The x-value.
     */
    public Number getX(int series, int item) {
        return new Double(getXValue(series, item));
    }
    
    /**
     * Returns the x-value (as a double primitive) for an item within a series.
     * 
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     * 
     * @return The value.
     */
    public double getXValue(int series, int item) {
        TimePeriod period = (TimePeriod) this.values.getRowKey(item);
        return getXValue(period);
    }

    /**
     * Returns the starting X value for the specified series and item.
     *
     * @param series  the series (zero-based index).
     * @param item  the item within a series (zero-based index).
     *
     * @return The starting X value for the specified series and item.
     */
    public Number getStartX(int series, int item) {
        return new Double(getStartXValue(series, item));
    }

    /**
     * Returns the start x-value (as a double primitive) for an item within 
     * a series.
     * 
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     * 
     * @return The value.
     */
    public double getStartXValue(int series, int item) {
        TimePeriod period = (TimePeriod) this.values.getRowKey(item);
        return period.getStart().getTime();
    }

    /**
     * Returns the ending X value for the specified series and item.
     *
     * @param series  the series (zero-based index).
     * @param item  the item within a series (zero-based index).
     *
     * @return The ending X value for the specified series and item.
     */
    public Number getEndX(int series, int item) {
        return new Double(getEndXValue(series, item));
    }

    /**
     * Returns the end x-value (as a double primitive) for an item within 
     * a series.
     * 
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     * 
     * @return The value.
     */
    public double getEndXValue(int series, int item) {
        TimePeriod period = (TimePeriod) this.values.getRowKey(item);
        return period.getEnd().getTime();
    }
 
    /**
     * Returns the y-value for an item within a series.
     *
     * @param series  the series (zero-based index).
     * @param item  the item (zero-based index).
     *
     * @return The y-value (possibly <code>null</code>).
     */
    public Number getY(int series, int item) {
        return this.values.getValue(item, series);
    }
    
    /**
     * Returns the starting Y value for the specified series and item.
     *
     * @param series  the series (zero-based index).
     * @param item  the item within a series (zero-based index).
     *
     * @return The starting Y value for the specified series and item.
     */
    public Number getStartY(int series, int item) {
        return getY(series, item);
    }
    
    /**
     * Returns the ending Y value for the specified series and item.
     *
     * @param series  the series (zero-based index).
     * @param item  the item within a series (zero-based index).
     *
     * @return The ending Y value for the specified series and item.
     */
    public Number getEndY(int series, int item) {
        return getY(series, item);
    }
    
    /**
     * Returns the x-value for a time period.
     *
     * @param period  the time period.
     *
     * @return The x-value.
     */
    private long getXValue(TimePeriod period) {
        long result = 0L;
        if (this.xPosition == TimePeriodAnchor.START) {
            result = period.getStart().getTime();
        }
        else if (this.xPosition == TimePeriodAnchor.MIDDLE) {
            long t0 = period.getStart().getTime();
            long t1 = period.getEnd().getTime();
            result = t0 + (t1 - t0) / 2L;
        }
        else if (this.xPosition == TimePeriodAnchor.END) {
            result = period.getEnd().getTime();
        }
        return result;
    }
    
    /**
     * Returns the minimum x-value in the dataset.
     *
     * @param includeInterval  a flag that determines whether or not the
     *                         x-interval is taken into account.
     * 
     * @return The minimum value.
     */
    public double getDomainLowerBound(boolean includeInterval) {
        double result = Double.NaN;
        Range r = getDomainBounds(includeInterval);
        if (r != null) {
            result = r.getLowerBound();
        }
        return result;
    }

    /**
     * Returns the maximum x-value in the dataset.
     *
     * @param includeInterval  a flag that determines whether or not the
     *                         x-interval is taken into account.
     * 
     * @return The maximum value.
     */
    public double getDomainUpperBound(boolean includeInterval) {
        double result = Double.NaN;
        Range r = getDomainBounds(includeInterval);
        if (r != null) {
            result = r.getUpperBound();
        }
        return result;
    }

    /**
     * Returns the range of the values in this dataset's domain.
     * 
     * @param includeInterval  a flag that controls whether or not the
     *                         x-intervals are taken into account.
     *
     * @return The range.
     */
    public Range getDomainBounds(boolean includeInterval) {
        List keys = this.values.getRowKeys();
        if (keys.isEmpty()) {
            return null;
        }
        
        TimePeriod first = (TimePeriod) keys.get(0);
        TimePeriod last = (TimePeriod) keys.get(keys.size() - 1);
        
        if (!includeInterval || this.domainIsPointsInTime) {
            return new Range(getXValue(first), getXValue(last));
        }
        else {
            return new Range(
                first.getStart().getTime(), last.getEnd().getTime()
            );
        }
    }
    
    /**
     * Tests this dataset for equality with an arbitrary object.
     * 
     * @param obj  the object (<code>null</code> permitted).
     * 
     * @return A boolean.
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof TimeTableXYDataset)) {
            return false;
        }
        TimeTableXYDataset that = (TimeTableXYDataset) obj;
        if (this.domainIsPointsInTime != that.domainIsPointsInTime) {
            return false;
        }
        if (this.xPosition != that.xPosition) {
            return false;
        }
        if (!this.workingCalendar.getTimeZone().equals(
            that.workingCalendar.getTimeZone())
        ) {
            return false;
        }
        if (!this.values.equals(that.values)) {
            return false;
        }
        return true;
    }
    
    /**
     * Returns a clone of this dataset.
     * 
     * @return A clone.
     * 
     * @throws CloneNotSupportedException if the dataset cannot be cloned.
     */
    public Object clone() throws CloneNotSupportedException {
        TimeTableXYDataset clone = (TimeTableXYDataset) super.clone();
        clone.values = (DefaultKeyedValues2D) this.values.clone();
        clone.workingCalendar = (Calendar) this.workingCalendar.clone();
        return clone;
    }

}