今更ながらPPAPを作ってみた。

Ppap.java

package satomaru.quiz;

import java.util.Random;
import java.util.function.Consumer;
import java.util.function.Supplier;

public final class Ppap {

	public enum Elements {
		APPLE, PEN, PINEAPPLE
	}

	private static final Elements[] EXPECTEDS = {
		Elements.PEN,
		Elements.PINEAPPLE,
		Elements.APPLE,
		Elements.PEN
	};

	public static void main(String[] args) {
		Random random = new Random();
		Elements[] elements = Elements.values();
		Ppap me = new Ppap();
		me.execute(() -> elements[random.nextInt(elements.length)] , System.out::println);
	}

	public boolean execute(Supplier<Elements> in, Consumer<Elements> out) {
		int progress = 0;

		do {
			Elements element = in.get();

			if (element == null) {
				return false;
			}

			out.accept(element);

			if (element == EXPECTEDS[progress]) {
				++progress;
			} else if (progress != 0) {
				progress = (element == EXPECTEDS[0]) ? 1 : 0;
			}
		} while (progress < EXPECTEDS.length);

		return true;
	}
}

PpapTest.java

package satomaru.quiz;

import static org.junit.Assert.*;

import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.junit.Before;
import org.junit.Test;

import satomaru.quiz.Ppap.Elements;

public class PpapTest {

	private Ppap tested;

	@Before
	public void setUp() {
		tested = new Ppap();
	}

	@Test
	public void test() {
		ArrayDeque<Elements> elements = new ArrayDeque<>();
		elements.add(Elements.PEN);
		elements.add(Elements.PINEAPPLE);
		elements.add(Elements.PEN);
		elements.add(Elements.PINEAPPLE);
		elements.add(Elements.APPLE);
		elements.add(Elements.PEN);
		elements.add(Elements.PINEAPPLE);
		elements.add(Elements.APPLE);
		elements.add(Elements.PEN);

		List<Elements> expected = Arrays.asList(
				Elements.PEN,
				Elements.PINEAPPLE,
				Elements.PEN,
				Elements.PINEAPPLE,
				Elements.APPLE,
				Elements.PEN
		);

		ArrayList<Elements> actual = new ArrayList<>();
		assertTrue(tested.execute(elements::poll, actual::add));
		assertEquals(expected, actual);
	}
}