org.apache.flink.graph

Interface NeighborsFunction<K,VV,EV,O>

Type Parameters:

K - the vertex key type

VV - the vertex value type

EV - the edge value type

O - the type of the return value

All Superinterfaces:

Function, Serializable

public interface NeighborsFunction<K,VV,EV,O>
extends Function, Serializable

Interface to be implemented by the function applied to a vertex neighborhood in the Graph.groupReduceOnNeighbors(NeighborsFunction, EdgeDirection) method.

Method Summary

Modifier and Type	Method and Description
void	iterateNeighbors(Iterable<Tuple3<K,Edge<K,EV>,Vertex<K,VV>>> neighbors, Collector<O> out) This method is called per vertex and can iterate over all of its neighbors with the specified direction.

Method Detail

iterateNeighbors

void iterateNeighbors(Iterable<Tuple3<K,Edge<K,EV>,Vertex<K,VV>>> neighbors,
                      Collector<O> out)
               throws Exception

This method is called per vertex and can iterate over all of its neighbors with the specified direction.

If called with EdgeDirection.OUT the group will contain the out-edges and neighboring vertices of the grouping vertex. If called with EdgeDirection.IN the group will contain the in-edges and neighboring vertices of the grouping vertex. If called with EdgeDirection.ALL the group will contain all edges and neighboring vertices of the grouping vertex.

The method can emit any number of output elements, including none.

Parameters:

neighbors - the neighbors of the grouping vertex. The first filed of each Tuple3 is the ID of the grouping vertex. The second field is the neighboring edge, and the third field is the neighboring vertex.

out - the collector to emit results to

Throws:

Exception