105 lines
2.5 KiB
Java
105 lines
2.5 KiB
Java
// enums/RoShamBo1.java
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// (c)2021 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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// Demonstration of multiple dispatching
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// {java enums.RoShamBo1}
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package enums;
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import java.util.*;
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import static enums.Outcome.*;
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interface Item {
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Outcome compete(Item it);
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Outcome eval(Paper p);
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Outcome eval(Scissors s);
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Outcome eval(Rock r);
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}
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class Paper implements Item {
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@Override public Outcome compete(Item it) {
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return it.eval(this);
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}
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@Override
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public Outcome eval(Paper p) { return DRAW; }
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@Override
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public Outcome eval(Scissors s) { return WIN; }
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@Override
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public Outcome eval(Rock r) { return LOSE; }
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@Override public String toString() {
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return "Paper";
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}
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}
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class Scissors implements Item {
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@Override public Outcome compete(Item it) {
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return it.eval(this);
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}
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@Override
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public Outcome eval(Paper p) { return LOSE; }
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@Override
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public Outcome eval(Scissors s) { return DRAW; }
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@Override
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public Outcome eval(Rock r) { return WIN; }
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@Override public String toString() {
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return "Scissors";
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}
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}
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class Rock implements Item {
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@Override public Outcome compete(Item it) {
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return it.eval(this);
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}
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@Override
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public Outcome eval(Paper p) { return WIN; }
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@Override
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public Outcome eval(Scissors s) { return LOSE; }
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@Override
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public Outcome eval(Rock r) { return DRAW; }
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@Override public String toString() {
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return "Rock";
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}
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}
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public class RoShamBo1 {
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static final int SIZE = 20;
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private static Random rand = new Random(47);
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public static Item newItem() {
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switch(rand.nextInt(3)) {
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default:
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case 0: return new Scissors();
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case 1: return new Paper();
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case 2: return new Rock();
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}
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}
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public static void match(Item a, Item b) {
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System.out.println(
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a + " vs. " + b + ": " + a.compete(b));
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}
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public static void main(String[] args) {
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for(int i = 0; i < SIZE; i++)
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match(newItem(), newItem());
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}
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}
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/* Output:
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Rock vs. Rock: DRAW
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Paper vs. Rock: WIN
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Paper vs. Rock: WIN
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Paper vs. Rock: WIN
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Scissors vs. Paper: WIN
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Scissors vs. Scissors: DRAW
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Scissors vs. Paper: WIN
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Rock vs. Paper: LOSE
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Paper vs. Paper: DRAW
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Rock vs. Paper: LOSE
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Paper vs. Scissors: LOSE
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Paper vs. Scissors: LOSE
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Rock vs. Scissors: WIN
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Rock vs. Paper: LOSE
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Paper vs. Rock: WIN
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Scissors vs. Paper: WIN
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Paper vs. Scissors: LOSE
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Paper vs. Scissors: LOSE
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Paper vs. Scissors: LOSE
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Paper vs. Scissors: LOSE
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*/
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