// =========================== Vertex Degree ============================
MapOperator projectEdge = MapOperator.builder(new ProjectEdge())
.input(edges).name("Project Edge").build();
ReduceOperator edgeCounter = ReduceOperator.builder(new CountEdges(), IntValue.class, 0)
.input(projectEdge).name("Count Edges for Vertex").build();
ReduceOperator countJoiner = ReduceOperator.builder(new JoinCountsAndUniquify(), IntValue.class, 0)
.keyField(IntValue.class, 1)
.input(edgeCounter).name("Join Counts").build();