Bug 138828 Export data column are disordered
Steps to reproduce: 1.Add a sample data source and a data set with table "CUSTOMERS" 2.Preview in Web Viewer 3.Click "Export data", choose columns "CUSTOMERNAME","PHONE","CITY","STATE" to be exported, click "OK" Expected result: The exported columns is alphabetic order or the same order as selected columns Actual result: The exported columns is disordered. they are "STATE","CITY","CUSTOMERNAME","PHONE".
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/service/ReportEngineService.java
* @param filters
	 * @param locale
	 * @param outputStream
	 * @throws RemoteException
	 */
	public void extractData( IReportDocument document, String resultSetName,
			Set columns, Locale locale, OutputStream outputStream )
			throws RemoteException
	{
		assert document != null;
		assert resultSetName != null && resultSetName.length( ) > 0;
		assert columns != null && !columns.isEmpty( );
		String[] columnNames = new String[columns.size( )];
		Iterator iSelectedColumns = columns.iterator( );
		for ( int i = 0; iSelectedColumns.hasNext( ); i++ )
		{
			columnNames[i] = (String) iSelectedColumns.next( );
		}
		IDataExtractionTask dataTask = null;
		IExtractionResults result = null;
		IDataIterator iData = null;
		try
		{
			synchronized ( this.getClass( ) )
			{
				dataTask = engine.createDataExtractionTask( document );
			}
			dataTask.selectResultSet( resultSetName );
			dataTask.selectColumns( columnNames );
			dataTask.setLocale( locale );