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.impl.DataPackageImpl#getQuery()
		 * @generated
		 */
		EClass QUERY = eINSTANCE.getQuery( );
		/**
		 * The meta object literal for the '<em><b>Definition</b></em>' attribute feature.
		 * <!-- begin-user-doc -->
		 * <!-- end-user-doc -->
		 * @generated
		 */
		EAttribute QUERY__DEFINITION = eINSTANCE.getQuery_Definition( );
		/**
		 * The meta object literal for the '<em><b>Rules</b></em>' containment reference list feature.
		 * <!-- begin-user-doc -->
		 * <!-- end-user-doc -->
		 * @generated
		 */
		EReference QUERY__RULES = eINSTANCE.getQuery_Rules( );
		/**
		 * The meta object literal for the '{@link org.eclipse.birt.chart.model.data.impl.RuleImpl <em>Rule</em>}' class.
		 * <!-- begin-user-doc -->
		 * <!-- end-user-doc -->
		 * @see org.eclipse.birt.chart.model.data.impl.RuleImpl
		 * @see org.eclipse.birt.chart.model.data.impl.DataPackageImpl#getRule()
		 * @generated
		 */
		EClass RULE = eINSTANCE.getRule( );
		/**
		 * The meta object literal for the '<em><b>Type</b></em>' attribute feature.
		 * <!-- begin-user-doc -->