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/util/DataAdapterFactory.java
/**
	 * Creates a new adapter for an object of class '{@link org.eclipse.birt.chart.model.data.SampleData <em>Sample Data</em>}'.
	 * <!-- begin-user-doc --> This default
	 * implementation returns null so that we can easily ignore cases; it's useful to ignore a case when inheritance
	 * will catch all the cases anyway. <!-- end-user-doc -->
	 * @return the new adapter.
	 * @see org.eclipse.birt.chart.model.data.SampleData
	 * @generated
	 */
	public Adapter createSampleDataAdapter( )
	{
		return null;
	}
	/**
	 * Creates a new adapter for an object of class '{@link org.eclipse.birt.chart.model.data.SeriesDefinition <em>Series Definition</em>}'.
	 * <!-- begin-user-doc -->
	 * This default implementation returns null so that we can easily ignore cases; it's useful to ignore a case when
	 * inheritance will catch all the cases anyway. <!-- end-user-doc -->
	 * @return the new adapter.
	 * @see org.eclipse.birt.chart.model.data.SeriesDefinition
	 * @generated
	 */
	public Adapter createSeriesDefinitionAdapter( )
	{
		return null;
	}
	/**
	 * Creates a new adapter for an object of class '{@link org.eclipse.birt.chart.model.data.SeriesGrouping <em>Series Grouping</em>}'.
	 * <!-- begin-user-doc --> This
	 * default implementation returns null so that we can easily ignore cases; it's useful to ignore a case when