OnJava8-Examples/patterns/PaperScissorsRock.java

70 lines
1.7 KiB
Java

// patterns/PaperScissorsRock.java
// (c)2021 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.
// Demonstration of multiple dispatching.
import java.util.*;
import java.util.function.*;
import java.util.stream.*;
import enums.Outcome;
import static enums.Outcome.*;
import enums.Item;
import enums.Paper;
import enums.Scissors;
import enums.Rock;
import onjava.*;
import static onjava.Tuple.*;
class ItemFactory {
static List<Supplier<Item>> items =
Arrays.asList(
Scissors::new, Paper::new, Rock::new);
static final int SZ = items.size();
private static SplittableRandom rand =
new SplittableRandom(47);
public static Item newItem() {
return items.get(rand.nextInt(SZ)).get();
}
public static Tuple2<Item,Item> newPair() {
return tuple(newItem(), newItem());
}
}
class Compete {
public static Outcome match(Tuple2<Item,Item> p) {
System.out.print(p.a1 + " -> " + p.a2 + " : ");
return p.a1.compete(p.a2);
}
}
public class PaperScissorsRock {
public static void main(String[] args) {
Stream.generate(ItemFactory::newPair)
.limit(20)
.map(Compete::match)
.forEach(System.out::println);
}
}
/* Output:
Scissors -> Rock : LOSE
Scissors -> Paper : WIN
Rock -> Paper : LOSE
Rock -> Rock : DRAW
Rock -> Paper : LOSE
Paper -> Scissors : LOSE
Rock -> Paper : LOSE
Scissors -> Scissors : DRAW
Scissors -> Rock : LOSE
Scissors -> Paper : WIN
Scissors -> Rock : LOSE
Paper -> Scissors : LOSE
Rock -> Rock : DRAW
Scissors -> Scissors : DRAW
Paper -> Paper : DRAW
Scissors -> Paper : WIN
Scissors -> Rock : LOSE
Scissors -> Paper : WIN
Rock -> Paper : LOSE
Rock -> Scissors : WIN
*/