Bug 190769 [Regression]The attached report pop up exception when preview
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/data/dte/QueryResultSet.java
import org.eclipse.birt.data.engine.api.IResultMetaData;
import org.eclipse.birt.data.engine.api.IScriptExpression;
import org.eclipse.birt.data.engine.api.ISubqueryDefinition;
import org.eclipse.birt.report.engine.api.DataSetID;
import org.eclipse.birt.report.engine.data.IDataEngine;
import org.eclipse.birt.report.engine.executor.ExecutionContext;
import org.eclipse.birt.report.engine.extension.IBaseResultSet;
import org.eclipse.birt.report.engine.extension.IQueryResultSet;
public class QueryResultSet implements IQueryResultSet
{
	protected IBaseResultSet parent;
	protected DataSetID id;
	protected long rowId = -1;
	/**
	 * result iterator object
	 */
	protected IResultIterator rs = null;
	protected long[] rowIdOfGroups;
	/**
	 * data engine
	 */
	protected IDataEngine dataEngine = null;
	private ExecutionContext context;
	private IBaseQueryDefinition queryDefn;
	private IQueryResults queryResults;
	private static IResultMetaData emptyResultMetaData = new EmptyResultMetaData( );
	/**
	 * 
	 */
	protected static Logger logger = Logger.getLogger( QueryResultSet.class