class EmptyGraph extends GraphGeneratorBase<LongValue, NullValue, NullValue> {

	@Override
	public Graph<LongValue, NullValue, NullValue> generate() {
		Preconditions.checkState(vertexCount >= 0);

		// Vertices
		DataSet<Vertex<LongValue, NullValue>> vertices = GraphGeneratorUtils.vertexSequence(env, parallelism, vertexCount);

		// Edges
		DataSource<Edge<LongValue, NullValue>> edges = env
			.fromCollection(Collections.<Edge<LongValue, NullValue>>emptyList(), TypeInformation.of(new TypeHint<Edge<LongValue, NullValue>>(){}))
				.setParallelism(parallelism)
				.name("Empty edge set");

		// Graph
		return Graph.fromDataSet(vertices, edges, env);
	}

	public  EmptyGraph(ExecutionEnvironment env, long vertexCount);

}