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/util/sort/IJSSortHelper.java
{
	/**
	 * 
	 * @return the target level
	 */
	public DimLevel getTargetLevel( );
	
	/**
	 * 
	 * @param row
	 * @return
	 * @throws DataException
	 */
	public Object evaluate( IResultRow row ) throws DataException;
	
	/**
	 * 
	 * @return
	 */
	public ISortDefinition getSortDefinition( );
	
	/**
	 * close this helper to clean up the registered javascript objects.
	 */
	public void close( );
}