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/impl/DataPackageImpl.java
/***********************************************************************
 * Copyright (c) 2004 Actuate Corporation.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * Actuate Corporation - initial API and implementation
 ***********************************************************************/
package org.eclipse.birt.chart.model.data.impl;
import org.eclipse.birt.chart.model.ModelPackage;
import org.eclipse.birt.chart.model.attribute.AttributePackage;
import org.eclipse.birt.chart.model.attribute.impl.AttributePackageImpl;
import org.eclipse.birt.chart.model.component.ComponentPackage;
import org.eclipse.birt.chart.model.component.impl.ComponentPackageImpl;
import org.eclipse.birt.chart.model.data.Action;
import org.eclipse.birt.chart.model.data.BaseSampleData;
import org.eclipse.birt.chart.model.data.BubbleDataSet;
import org.eclipse.birt.chart.model.data.DataElement;
import org.eclipse.birt.chart.model.data.DataFactory;
import org.eclipse.birt.chart.model.data.DataPackage;
import org.eclipse.birt.chart.model.data.DataSet;
import org.eclipse.birt.chart.model.data.DateTimeDataElement;
import org.eclipse.birt.chart.model.data.DateTimeDataSet;
import org.eclipse.birt.chart.model.data.DifferenceDataSet;