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
* @return the meta object for class '<em>Date Time Data Element</em>'.
	 * @see org.eclipse.birt.chart.model.data.DateTimeDataElement
	 * @generated
	 */
	EClass getDateTimeDataElement( );
	/**
	 * Returns the meta object for the attribute '{@link org.eclipse.birt.chart.model.data.DateTimeDataElement#getValue <em>Value</em>}'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the meta object for the attribute '<em>Value</em>'.
	 * @see org.eclipse.birt.chart.model.data.DateTimeDataElement#getValue()
	 * @see #getDateTimeDataElement()
	 * @generated
	 */
	EAttribute getDateTimeDataElement_Value( );
	/**
	 * Returns the meta object for class '{@link org.eclipse.birt.chart.model.data.DateTimeDataSet <em>Date Time Data Set</em>}'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the meta object for class '<em>Date Time Data Set</em>'.
	 * @see org.eclipse.birt.chart.model.data.DateTimeDataSet
	 * @generated
	 */
	EClass getDateTimeDataSet( );
	/**
	 * Returns the meta object for class '{@link org.eclipse.birt.chart.model.data.DifferenceDataSet <em>Difference Data Set</em>}'.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @return the meta object for class '<em>Difference Data Set</em>'.
	 * @see org.eclipse.birt.chart.model.data.DifferenceDataSet
	 * @generated
	 */