protected void describe() {
UpdateFlowFactory uf = new UpdateFlowFactory();
ExOperatorFactory f = new ExOperatorFactory();
CoreOperatorFactory c = new CoreOperatorFactory();
Confluent<Ex1> in = c.confluent(pIn1, pIn2);
Simple simple = uf.simple(in);
Checkpoint<Ex1> cp = c.checkpoint(simple.out);
Cogroup cog = f.cogroup(cp, c.empty(Ex2.class));
c.stop(cog.r2);
pOut1.add(cog.r1);
}