public Set<T> getAdjacencyList(int vertex) {
        EdgeSet<T> e = getEdgeSet(vertex);
        return (e == null) 
            ? Collections.<T>emptySet() 
            : new AdjacencyListView(e);
    }
public Set < T > getAdjacencyList ( int vertex ) { EdgeSet < T > e = getEdgeSet ( vertex ) ; return ( e == null ) ? Collections . < T > emptySet ( ) : new AdjacencyListView ( e ) ; }
{@inheritDoc}