java concurrency of CopyOnWriteArraySet

java concurrency of CopyOnWriteArraySet

CopyOnWriteArraySet is implemented based CopyOnWriteArrayList holding CopyOnWriteArrayList internal object, which iterator is CopyOnWriteArrayList iterator, the Add operation or by addAllAbsent addIfAbsent deduplication.

example

package javalearn.javabase.concurrent;

import lombok.extern.slf4j.Slf4j;

import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;

@Slf4j
public class CopyOnWriteArraySetTest {
    private static CopyOnWriteArraySet<String> set = new CopyOnWriteArraySet<>();

    private static int capcity = 5;

    //private static HashSet<String> set =new HashSet<>();
    public static void main(String[] args) {
        CopyOnWriteArraySetTest.InnerThread t1 = new InnerThread();
        CopyOnWriteArraySetTest.InnerThread t2 = new InnerThread();
        t1.start();
        t2.start();
        try {
            Thread.sleep(1000);
            log.info("collection:{} ",set.toString());

        } catch (InterruptedException e) {
            e.printStackTrace();
        }


    }

    static class InnerThread extends Thread {
        @Override
        public void run() {
            for (int i = 0; i < capcity; i++) {
                set.add(String.valueOf(i));
                set.add(String.valueOf(i));
                iterator(set);
            }
        }
    }

    public static void iterator(Set set) {
        Iterator iterator = set.iterator();
        while (iterator.hasNext()) {
            iterator.next();
        }

    }
}

result

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