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/util/DataSwitch.java
* @generated
	 */
	protected static DataPackage modelPackage;
	/**
	 * Creates an instance of the switch.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 */
	public DataSwitch( )
	{
		if ( modelPackage == null )
		{
			modelPackage = DataPackage.eINSTANCE;
		}
	}
	/**
	 * Calls <code>caseXXX</code> for each class of the model until one returns a non null result; it yields that result.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the first non-null result returned by a <code>caseXXX</code> call.
	 * @generated
	 */
	public Object doSwitch( EObject theEObject )
	{
		return doSwitch( theEObject.eClass( ), theEObject );
	}
	/**
	 * Calls <code>caseXXX</code> for each class of the model until one returns a non null result; it yields that result.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the first non-null result returned by a <code>caseXXX</code> call.
	 * @generated