Sample of a source emitting random integers

RandomNumberSource.java

package streams;

import akka.stream.Attributes;
import akka.stream.Outlet;
import akka.stream.SourceShape;
import akka.stream.stage.AbstractOutHandler;
import akka.stream.stage.GraphStage;
import akka.stream.stage.GraphStageLogic;
import akka.stream.stage.OutHandler;

import java.util.Random;

public class RandomNumberSource extends GraphStage<SourceShape<Integer>> {

  public final Outlet<Integer> out = Outlet.create("RandomNumberSource.out");

  private final SourceShape<Integer> shape = SourceShape.of(out);

  @Override
  public SourceShape<Integer> shape() {
    return shape;
  }

  @Override
  public GraphStageLogic createLogic(Attributes inheritedAttributes) {
    return new GraphStageLogic(shape) {

      private final Random random = new Random();

      {
        setHandler(out, new AbstractOutHandler() {
          @Override
          public void onPull() throws Exception {
            push(out, random.nextInt());
          }
        });
      }

    };
  }

}