Temir.Dice created by valery1707 - https://repl.it/FIal/0

Temir.Dice.java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Random;
import java.util.stream.IntStream;

class Main {
	public static void main(String[] args) {
		Dice dice = new RandomDice(6);
		System.out.println("dice6.roll() = " + dice.roll());
		System.out.println("dice6.roll() = " + dice.roll());
		System.out.println("dice6.roll(2) = " + dice.roll(2));
		System.out.println("dice6.roll(6) = " + dice.roll(6));

		Dice history = new DiceWithHistory(new RandomDice(6));
		history.roll(2);
		history.roll(2);
		history.roll(5);
		System.out.println("history = " + history);

		history = new DiceWithHistory(new FrozenDice(6, 5));
		history.roll(2);
		history.roll(2);
		history.roll(5);
		System.out.println("frozen = " + history);
	}

	public interface Dice {
		Roll roll();

		Roll roll(int count);
	}

	public static class RandomDice implements Dice {
		private final int max;
		private final Random generator = new Random();

		public RandomDice(int max) {
			this.max = max;
		}

		@Override
		public Roll roll() {
			return roll(1);
		}

		@Override
		public Roll roll(int count) {
			//А вот так можно на Java8
//			return new Roll(generator
//					.ints(count, 0, max)
//					.map(v -> v + 1)
//					.toArray()
//			);
			int[] values = new int[count];
			for (int i = 0; i < count; i++) {
				values[i] = rollImpl();
			}
			return new Roll(values);
		}

		protected int rollImpl() {
			return generator.nextInt(max) + 1;
		}
	}

	public static class Roll {
		private final int count;
		private final int[] values;
		private final int min;
		private final int max;
		private final double ave;
		private final int sum;

		public Roll(int[] values) {
			count = values.length;
			this.values = values;
			//Тут куски Java8 - влом писать самому
			min = IntStream.of(values).min().getAsInt();
			max = IntStream.of(values).max().getAsInt();
			ave = IntStream.of(values).average().getAsDouble();
			sum = IntStream.of(values).sum();
		}

		@Override
		public String toString() {
			return "Roll{" +
				   "count=" + count +
				   ", values=" + Arrays.toString(values) +
				   ", min=" + min +
				   ", max=" + max +
				   ", ave=" + ave +
				   ", sum=" + sum +
				   '}';
		}
	}

	public static class DiceWithHistory implements Dice {
		private final RandomDice dice;
		private final List<Roll> history = new ArrayList<>();

		public DiceWithHistory(RandomDice dice) {
			this.dice = dice;
		}

		@Override
		public Roll roll() {
			Roll roll = dice.roll();
			history.add(roll);
			return roll;
		}

		@Override
		public Roll roll(int count) {
			Roll roll = dice.roll(count);
			history.add(roll);
			return roll;
		}

		@Override
		public String toString() {
			return "DiceWithHistory{" +
				   "history=" + history +
				   '}';
		}
	}

	public static class FrozenDice extends RandomDice {
		private final int value;

		public FrozenDice(int max, int value) {
			super(max);
			this.value = value;
		}

		@Override
		protected int rollImpl() {
			return value;
		}
	}
}