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
* <!-- begin-user-doc -->
		 * <!-- end-user-doc -->
		 * @see org.eclipse.birt.chart.model.data.impl.GanttDataSetImpl
		 * @see org.eclipse.birt.chart.model.data.impl.DataPackageImpl#getGanttDataSet()
		 * @generated
		 */
		EClass GANTT_DATA_SET = eINSTANCE.getGanttDataSet( );
		/**
		 * The meta object literal for the '{@link org.eclipse.birt.chart.model.data.impl.NumberDataElementImpl <em>Number Data Element</em>}' class.
		 * <!-- begin-user-doc -->
		 * <!-- end-user-doc -->
		 * @see org.eclipse.birt.chart.model.data.impl.NumberDataElementImpl
		 * @see org.eclipse.birt.chart.model.data.impl.DataPackageImpl#getNumberDataElement()
		 * @generated
		 */
		EClass NUMBER_DATA_ELEMENT = eINSTANCE.getNumberDataElement( );
		/**
		 * The meta object literal for the '<em><b>Value</b></em>' attribute feature.
		 * <!-- begin-user-doc -->
		 * <!-- end-user-doc -->
		 * @generated
		 */
		EAttribute NUMBER_DATA_ELEMENT__VALUE = eINSTANCE.getNumberDataElement_Value( );
		/**
		 * The meta object literal for the '{@link org.eclipse.birt.chart.model.data.impl.NumberDataSetImpl <em>Number Data Set</em>}' class.
		 * <!-- begin-user-doc -->
		 * <!-- end-user-doc -->
		 * @see org.eclipse.birt.chart.model.data.impl.NumberDataSetImpl
		 * @see org.eclipse.birt.chart.model.data.impl.DataPackageImpl#getNumberDataSet()
		 * @generated