Bug 132515 Expression like "Toltal.rank(Tolta.ave(row[a]),ture,Null,1)" is return an error
Description: Add an expression like "Toltal.rank(Tolta.ave(row[a]),ture,Null,1)" is return an error.The nesting "Toltal" seem not to be work. Step to reproduce: 1.new a datasource and dataset 2.drag the dataset to layout veiw for a table 3.set a group on the table 4.Insert a data into the group header with the expression e.g. "Toltal.rank(Tolta.ave(row[a]),ture,Null,1)" Actual result: An error was thrown out Expected result: It should work correctly in order to support some requirments
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/executor/transform/group/GroupInstanceSorter.java
{
	private ResultSetPopulator populator;
	private GroupProcessorManager groupProcessor;
	GroupInstanceSorter( GroupProcessorManager gp )
	{
		this.populator = gp.getResultSetPopulator( );
		this.groupProcessor = gp;
	}
	/**
	 * Dealing with group sorting jobs.
	 * 
	 * @param cx
	 * @throws DataException
	 */
	void doGroupSorting( Context cx ) throws DataException
	{
		List groupLevels = new ArrayList( );
		List expressionList = new ArrayList( );
		populateGroupSortExpressions( expressionList, groupLevels );
		if ( expressionList.size( ) > 0 )
		{
			this.groupProcessor.calculateExpressionList( expressionList,
					groupLevels,
					IExpressionProcessor.SORT_ON_GROUP_EXPR );
			
			ArrayList[] groupArray = this.groupProcessor.getGroupCalculationUtil( )
					.getGroupInformationUtil( )
					.getGroupBoundaryInfos( );
			populateGroupBoundaryInfosSortings( cx, groupArray );