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
{
	private static final long serialVersionUID = 1L;
	private static final int MILLIS_IN_SECOND = 1000;
	private static final int MILLIS_IN_MINUTE = MILLIS_IN_SECOND * 60;
	private static final int MILLIS_IN_HOUR = MILLIS_IN_MINUTE * 60;
	private static final int MILLIS_IN_DAY = MILLIS_IN_HOUR * 24;
	private static final int[] iaUnitTypes = {
			Calendar.MILLISECOND,
			Calendar.SECOND,
			Calendar.MINUTE,
			Calendar.HOUR_OF_DAY,
			Calendar.DATE,
			Calendar.MONTH,
			Calendar.YEAR
	};
	private static final SimpleDateFormat _sdf = new SimpleDateFormat( "MM-dd-yyyy HH:mm:ss" ); 
	/**
	 * A zero-arg default constructor
	 */
	public CDateTime( )
	{
		super( );
	}
	/**
	 * A constructor that creates an instance from a given
	 * <code>java.util.Date</code> value
	 *