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
* <ul>
	 *   <li>each class,</li>
	 *   <li>each feature of each class,</li>
	 *   <li>each enum,</li>
	 *   <li>and each data type</li>
	 * </ul>
	 * <!-- end-user-doc -->
	 * @generated
	 */
	interface Literals
	{
		/**
		 * The meta object literal for the '{@link org.eclipse.birt.chart.model.data.impl.ActionImpl <em>Action</em>}' class.
		 * <!-- begin-user-doc -->
		 * <!-- end-user-doc -->
		 * @see org.eclipse.birt.chart.model.data.impl.ActionImpl
		 * @see org.eclipse.birt.chart.model.data.impl.DataPackageImpl#getAction()
		 * @generated
		 */
		EClass ACTION = eINSTANCE.getAction( );
		/**
		 * The meta object literal for the '<em><b>Type</b></em>' attribute feature.
		 * <!-- begin-user-doc -->
		 * <!-- end-user-doc -->
		 * @generated
		 */
		EAttribute ACTION__TYPE = eINSTANCE.getAction_Type( );
		/**
		 * The meta object literal for the '<em><b>Value</b></em>' containment reference feature.
		 * <!-- begin-user-doc -->