小编lul*_*omo的帖子

我正在尝试设计一个基于密钥的锁定工具:类似于正常的可重入锁定,而不是lock()和unlock(),你锁定(密钥)和解锁(密钥),合同中没有人会如果key.equals(key1),能够同时锁定(key1).

这段代码会起作用吗？是否有更有效的解决方案？我特别不喜欢while循环,同时试图将锁定放在地图中...

package luca;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.locks.ReentrantLock;

public class KeyedReentrantLock<K> {
    private ConcurrentMap<K, ReentrantLock> lockMap = new ConcurrentHashMap<K, ReentrantLock>();

    public void lock(K key) {
        ReentrantLock oldLock = lockMap.get(key);
        if (oldLock != null && oldLock.isHeldByCurrentThread()){
            // increase lock count and return.
            oldLock.lock();
            return;
        }
        ReentrantLock newLock = new ReentrantLock();
        newLock.lock();
        while ((oldLock = lockMap.putIfAbsent(key, newLock)) != null){
            // wait for the old lock to be released;
            oldLock.lock();
            oldLock.unlock();
        }
        return;
    }

    public void unlock(K key){
        ReentrantLock lock = …