// concurrent/Batter.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
import java.util.concurrent.*;
import onjava.Nap;

public class Batter {
 static class Eggs {}
 static class Milk {}
 static class Sugar {}
 static class Flour {}
 static <T> T prepare(T ingredient) {
 new Nap(0.1);
 return ingredient;
 }
 static <T> CompletableFuture<T> prep(T ingredient) {
 return CompletableFuture
 .completedFuture(ingredient)
 .thenApplyAsync(Batter::prepare);
 }
 public static CompletableFuture<Batter> mix() {
 CompletableFuture<Eggs> eggs = prep(new Eggs());
 CompletableFuture<Milk> milk = prep(new Milk());
 CompletableFuture<Sugar> sugar = prep(new Sugar());
 CompletableFuture<Flour> flour = prep(new Flour());
 CompletableFuture
 .allOf(eggs, milk, sugar, flour)
 .join();
 new Nap(0.1); // Mixing time
 return
 CompletableFuture.completedFuture(new Batter());
 }
}