### Question:
TimeTableXYDataset extends AbstractIntervalXYDataset implements Cloneable, PublicCloneable, IntervalXYDataset, DomainInfo,
                   TableXYDataset { public void clear() { if (this.values.getRowCount() > 0) { this.values.clear(); fireDatasetChanged(); } } TimeTableXYDataset();  TimeTableXYDataset(TimeZone zone);  TimeTableXYDataset(TimeZone zone, Locale locale); boolean getDomainIsPointsInTime(); void setDomainIsPointsInTime(boolean flag); TimePeriodAnchor getXPosition(); void setXPosition(TimePeriodAnchor anchor); void add(TimePeriod period, double y, Comparable seriesName); void add(TimePeriod period, Number y, Comparable seriesName,
                    boolean notify); void remove(TimePeriod period, Comparable seriesName); void remove(TimePeriod period, Comparable seriesName,
            boolean notify); void clear(); TimePeriod getTimePeriod(int item); @Override int getItemCount(); @Override int getItemCount(int series); @Override int getSeriesCount(); @Override Comparable getSeriesKey(int series); @Override Number getX(int series, int item); @Override double getXValue(int series, int item); @Override Number getStartX(int series, int item); @Override double getStartXValue(int series, int item); @Override Number getEndX(int series, int item); @Override double getEndXValue(int series, int item); @Override Number getY(int series, int item); @Override Number getStartY(int series, int item); @Override Number getEndY(int series, int item); @Override double getDomainLowerBound(boolean includeInterval); @Override double getDomainUpperBound(boolean includeInterval); @Override Range getDomainBounds(boolean includeInterval); @Override boolean equals(Object obj); @Override Object clone();  }### Answer:
@Test public void testClear() { TimeTableXYDataset d = new TimeTableXYDataset(); d.add(new Year(1999), 1.0, "Series 1"); assertEquals(d.getItemCount(), 1); assertEquals(d.getSeriesCount(), 1); d.add(new Year(2000), 2.0, "Series 2"); d.clear(); assertEquals(0, d.getItemCount()); assertEquals(0, d.getSeriesCount()); }