迭代器适配器方法惯用法

package t20211225;

import java.util.*;

/**
 * @Author: DengJia
 * @Date: 2021/12/26 10:04
 * @Description: 顺序迭代、逆序迭代、乱序迭代
 */

public class IterableClass implements Iterable<String> {
    protected String[] words = ("1 2 3 4 5 6 7 8 9 0").split(" ");

    @Override
    public Iterator<String> iterator() {
        return new Iterator<String>() {
            private int index = 0;

            @Override
            public boolean hasNext() {
                return index < words.length;
            }

            @Override
            public String next() {
                return words[index++];
            }

            @Override
            public void remove() {
                throw new UnsupportedOperationException();
            }
        };
    }

    public static void main(String[] args) {
        MultiIterableClass mic = new MultiIterableClass();
        System.out.print("顺序迭代：");
        for (String s : mic) {
            System.out.print(s + " ");
        }
        System.out.print("\n逆序迭代：");
        for (String s : mic.reversed()) {
            System.out.print(s + " ");
        }
        System.out.print("\n乱序迭代：");
        for (String s : mic.randomized()) {
            System.out.print(s + " ");
        }
    }
}

class MultiIterableClass extends IterableClass {
    public Iterable<String> reversed() {
        return () -> new Iterator<String>() {
            int current = words.length - 1;

            @Override
            public boolean hasNext() {
                return current > -1;
            }

            @Override
            public String next() {
                return words[current--];
            }

            @Override
            public void remove() {
                throw new UnsupportedOperationException();
            }
        };
    }

    public Iterable<String> randomized() {
        return () -> {
            // 洗牌
            List<String> shuffled = new ArrayList<>(Arrays.asList(words));
            Collections.shuffle(shuffled, new Random(47));
            return shuffled.iterator();
        };
    }
}

顺序迭代：1 2 3 4 5 6 7 8 9 0 
逆序迭代：0 9 8 7 6 5 4 3 2 1 
乱序迭代：4 6 3 1 8 7 2 5 0 9