Bug 182895 Support sort on Level attribute.
Currently in OLAP engine we only support sort on level key value. We should go ahead to support sort on level attribute value.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/olap/data/api/CubeQueryExecutorHelper.java
}
	/*
	 * (non-Javadoc)
	 * @see org.eclipse.birt.data.olap.data.api.ICubeQueryExcutorHelper#excute(org.eclipse.birt.data.olap.data.impl.AggregationDefinition[], org.eclipse.birt.data.olap.data.impl.StopSign)
	 */
	public IAggregationResultSet[] execute(
			AggregationDefinition[] aggregations, StopSign stopSign )
			throws IOException, BirtException
	{
		IAggregationResultSet[] resultSet = onePassExecute( aggregations,
				stopSign );
		
		applyAggrFilters( aggregations, resultSet, stopSign );
		
		applyAggrSort( resultSet );
		
		return resultSet;
	}	
	
	/**
	 * @param resultSet
	 * @throws DataException
	 */
	private void applyAggrSort( IAggregationResultSet[] resultSet )
			throws DataException
	{
		if ( !this.columnSort.isEmpty( ) )
		{
			IAggregationResultSet column = AggrSortHelper.sort( this.columnSort,
					resultSet );