StartSearch.java

public class StartSeach implements Node<SerialPipe, Collection<Haystack>> {
  public NodeResult execute(SerialPipe pipe, Collection<HayStack> haystacks){
    return pipe.fork(FindNeedle.class, haystacks);
  }  
}

FindNeedle.java

public class StartSeach implements Node<ParallelPipe, Haystack> {
  public NodeResult execute(ParallelPipe pipe, HayStack haystacks){
    // let's find the needle
    return pipe.join(HaystackSearched.class, needleFound);
  }  
}