Bug 202254 Exception is thrown when category values are null and type of X axis is set to DateTime
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/model/data/impl/DataFactoryImpl.java
* <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 */
	public SampleData createSampleData( )
	{
		SampleDataImpl sampleData = new SampleDataImpl( );
		return sampleData;
	}
	/**
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 */
	public SeriesDefinition createSeriesDefinition( )
	{
		SeriesDefinitionImpl seriesDefinition = new SeriesDefinitionImpl( );
		return seriesDefinition;
	}
	/**
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 */
	public SeriesGrouping createSeriesGrouping( )
	{
		SeriesGroupingImpl seriesGrouping = new SeriesGroupingImpl( );
		return seriesGrouping;
	}
	/**
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 */