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
* <!-- end-user-doc -->
		 * @generated
		 */
		EReference SAMPLE_DATA__ORTHOGONAL_SAMPLE_DATA = eINSTANCE.getSampleData_OrthogonalSampleData( );
		/**
		 * The meta object literal for the '<em><b>Ancillary Sample Data</b></em>' containment reference list feature.
		 * <!-- begin-user-doc -->
		 * <!-- end-user-doc -->
		 * @generated
		 */
		EReference SAMPLE_DATA__ANCILLARY_SAMPLE_DATA = eINSTANCE.getSampleData_AncillarySampleData( );
		/**
		 * The meta object literal for the '{@link org.eclipse.birt.chart.model.data.impl.SeriesDefinitionImpl <em>Series Definition</em>}' class.
		 * <!-- begin-user-doc -->
		 * <!-- end-user-doc -->
		 * @see org.eclipse.birt.chart.model.data.impl.SeriesDefinitionImpl
		 * @see org.eclipse.birt.chart.model.data.impl.DataPackageImpl#getSeriesDefinition()
		 * @generated
		 */
		EClass SERIES_DEFINITION = eINSTANCE.getSeriesDefinition( );
		/**
		 * The meta object literal for the '<em><b>Query</b></em>' containment reference feature.
		 * <!-- begin-user-doc -->
		 * <!-- end-user-doc -->
		 * @generated
		 */
		EReference SERIES_DEFINITION__QUERY = eINSTANCE.getSeriesDefinition_Query( );
		/**
		 * The meta object literal for the '<em><b>Series Palette</b></em>' containment reference feature.
		 * <!-- begin-user-doc -->