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
* @throws DataException
	 */
	private void populateGroupBoundaryInfoSortings( Context cx,
			ArrayList[] groupArray, int groupPosition, int groupIndex )
			throws DataException
	{
		Object[] sortKeys = new Object[this.populator.getQuery( ).getGrouping( )[groupPosition].getSorts( )
				.size( )];
		boolean[] sortDirections = new boolean[sortKeys.length];
		
		
		this.populator.getResultIterator( ).last( groupPosition + 1 );
		for ( int l = 0; l < sortKeys.length; l++ )
		{
			sortKeys[l] = ScriptEvalUtil.evalExpr( ( (ISortDefinition) this.populator.getQuery( )
					.getGrouping( )[groupPosition].getSorts( ).get( l ) ).getExpression( ),
					cx,
					this.groupProcessor.getExpressionProcessor( ).getScope( ),
					"GroupFilter",
					0 );
			sortDirections[l] = ( (ISortDefinition) this.populator.getQuery( )
					.getGrouping( )[groupPosition].getSorts( ).get( l ) ).getSortDirection( ) == ISortDefinition.SORT_ASC
					? true : false;
		}
		( (GroupBoundaryInfo) groupArray[groupPosition].get( groupIndex ) ).setSortCondition( sortKeys,
				sortDirections );
		this.populator.getResultIterator( ).next( );
	}
}