Bug 123219 Export data in attached file which has a table covers multiple page will throw exception.
Description: Export data in attached file which has a table covers multiple page will throw exception. Steps to reproduce: 1. Preview attached design file in viewer. 2. Select the table and click Export Data Expected result: No errors. Actual result: Exception Exception in: ReportEngineService.getMetaData( )
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/DataExtractionTask.java
* have the metadata be prepared
	 */
	protected boolean isMetaDataPrepared = false;
	
	/*
	 * map query to display name
	 */
	protected HashMap mapQueryToDispName;
	
	/*
	 * map query to value expressions
	 */
	protected HashMap mapQueryToValueExprs;
	
	/*
	 * map result set name to query
	 */
	protected HashMap mapResultSetNameToQuery;
	
	/**
	 * the logger
	 */
	protected static Logger logger = Logger.getLogger( DteDataEngine.class
			.getName( ) );
	
	public DataExtractionTask( ReportEngine engine, IReportRunnable runnable,
			ReportDocumentReader reader ) throws EngineException
	{
		super( engine, runnable );