question: private static void findOuterShells ( List shellList ) { for ( Iterator i = shellList . iterator ( ) ; i . hasNext ( ) ; ) { EdgeRing er = ( EdgeRing ) i . next ( ) ; EdgeRing outerHoleER = er . getOuterHole ( ) ; if ( outerHoleER != null && ! outerHoleER . isProcessed ( ) ) { er . setIncluded ( true ) ; outerHoleER . setProcessed ( true ) ; } } }
target:  For each outer hole finds and includes a single outer shell. This seeds the travesal algorithm for finding only polygonal shells.