question: public QLFDocument ( List < F > list , String docno , Map < String , String > extraProps ) { featureList = new MemoryLocalFeatureList < F > ( list ) ; iterator = list . iterator ( ) ; if ( extraProps != null ) props . putAll ( extraProps ) ; props . put ( "docno" , docno ) ; }
target:  Construct a new QLFDocument instance from the contents of the given feature list.