Bug 161219 Gantt chart with null datapoints fail to render
Create a dataset with two date columns, having some null date values Create a gantt chart Assign the dates to the gant series It fails to render and throw exception. Expected: null dates should be treated as: - 1 null date, 1 valid date ->one marker drawn, no line - 2 null dates -> skip rendering of datapoint If the decoration label is missing it should also not fail.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/util/CDateTime.java
/**
	 * Returns the year associated with this instance
	 * 
	 * @return The year associated with this instance
	 */
	public final int getYear( )
	{
		return get( Calendar.YEAR );
	}
	/**
	 * Returns the month (0-based) associated with this instance
	 * 
	 * @return The month associated with this instance
	 */
	public final int getMonth( )
	{
		return get( Calendar.MONTH );
	}
	/**
	 * Returns the day of the month associated with this instance
	 * 
	 * @return The day of the month associated with this instance
	 */
	public final int getDay( )
	{
		return get( Calendar.DATE );
	}
	/**
	 * Returns the hour (military) associated with this instance
	 *