java并发之CopyOnWriteArraySet

CopyOnWriteArraySet是基于CopyOnWriteArrayList实现的，持有CopyOnWriteArrayList的内部对象，它的迭代器也是CopyOnWriteArrayList的迭代器，add操作通过addAllAbsent或者addIfAbsent去重。

例子

1package javalearn.javabase.concurrent;
2
3import lombok.extern.slf4j.Slf4j;
4
5import java.util.HashSet;
6import java.util.Iterator;
7import java.util.Set;
8import java.util.concurrent.CopyOnWriteArraySet;
9
10@Slf4j
11public class CopyOnWriteArraySetTest {
12    private static CopyOnWriteArraySet<String> set = new CopyOnWriteArraySet<>();
13
14    private static int capcity = 5;
15
16    //private static HashSet<String> set =new HashSet<>();
17    public static void main(String[] args) {
18        CopyOnWriteArraySetTest.InnerThread t1 = new InnerThread();
19        CopyOnWriteArraySetTest.InnerThread t2 = new InnerThread();
20        t1.start();
21        t2.start();
22        try {
23            Thread.sleep(1000);
24            log.info("collection:{} ",set.toString());
25
26        } catch (InterruptedException e) {
27            e.printStackTrace();
28        }
29
30
31    }
32
33    static class InnerThread extends Thread {
34        @Override
35        public void run() {
36            for (int i = 0; i < capcity; i++) {
37                set.add(String.valueOf(i));
38                set.add(String.valueOf(i));
39                iterator(set);
40            }
41        }
42    }
43
44    public static void iterator(Set set) {
45        Iterator iterator = set.iterator();
46        while (iterator.hasNext()) {
47            iterator.next();
48        }
49
50    }
51}
52

结果

21:10:09.967 [main] INFO javalearn.javabase.concurrent.CopyOnWriteArraySetTest - collection:[0, 1, 2, 3, 4]