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/DataPackage.java
* @see org.eclipse.birt.chart.model.data.SeriesDefinition#getGrouping()
	 * @see #getSeriesDefinition()
	 * @generated
	 */
	EReference getSeriesDefinition_Grouping( );
	/**
	 * Returns the meta object for the attribute '{@link org.eclipse.birt.chart.model.data.SeriesDefinition#getSorting <em>Sorting</em>}'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the meta object for the attribute '<em>Sorting</em>'.
	 * @see org.eclipse.birt.chart.model.data.SeriesDefinition#getSorting()
	 * @see #getSeriesDefinition()
	 * @generated
	 */
	EAttribute getSeriesDefinition_Sorting( );
	/**
	 * Returns the meta object for class '{@link org.eclipse.birt.chart.model.data.SeriesGrouping <em>Series Grouping</em>}'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the meta object for class '<em>Series Grouping</em>'.
	 * @see org.eclipse.birt.chart.model.data.SeriesGrouping
	 * @generated
	 */
	EClass getSeriesGrouping( );
	/**
	 * Returns the meta object for the attribute '{@link org.eclipse.birt.chart.model.data.SeriesGrouping#isEnabled <em>Enabled</em>}'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the meta object for the attribute '<em>Enabled</em>'.
	 * @see org.eclipse.birt.chart.model.data.SeriesGrouping#isEnabled()
	 * @see #getSeriesGrouping()
	 * @generated
	 */