实现简单的对象锁_JAVA_编程开发_程序员俱乐部

class="java" name="code">
package com.zj.study.framework.lock.customlock;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.AbstractQueuedLongSynchronizer;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

public class ObjectLock implements Lock {
	private final Sync sycn;

	public ObjectLock(String lockKey) {
		super();
		sycn = new Sync(lockKey);
	}

	private static ConcurrentHashMap<String, Object> lockMap = new ConcurrentHashMap<>();

	private static class Sync extends AbstractQueuedLongSynchronizer {
		private final String lockKey;

		public Sync(String lockKey) {
			this.lockKey = lockKey;
		}

		@Override
		protected boolean tryAcquire(long arg) {
			if (lockMap.putIfAbsent(lockKey, lockKey) == null) {
				setExclusiveOwnerThread(Thread.currentThread());
				return true;
			}
			return false;
		}

		@Override
		protected boolean tryRelease(long arg) {
			if (lockMap.get(lockKey) == null)
				throw new UnsupportedOperationException();

			setExclusiveOwnerThread(null);
			setState(0);
			lockMap.remove(lockKey);
			return true;
		}

		@Override
		protected boolean isHeldExclusively() {
			return lockMap.contains(lockKey);
		}

		Condition newCondition() {
			return new ConditionObject();
		}

	}

	@Override
	public void lock() {
		sycn.acquire(1);
	}

	@Override
	public void lockInterruptibly() throws InterruptedException {
		sycn.acquireInterruptibly(1);
	}

	@Override
	public boolean tryLock() {
		return sycn.tryAcquire(1);
	}

	@Override
	public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {
		return sycn.tryAcquireNanos(1, unit.toNanos(time));
	}

	@Override
	public void unlock() {
		sycn.release(1);
	}

	@Override
	public Condition newCondition() {
		return sycn.newCondition();
	}

}

package com.zj.study.framework.lock.customlock;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;

import com.zj.study.framework.lock.Tools;

public class TestObjectLock {

	public void test() {
		final Lock lock1 = new ObjectLock("1");
		final Lock lock2 = new ObjectLock("2");
		class Worker extends Thread {
			public void run() {
				int r = Tools.getRandomInt(2);
				Lock lock;
				if (r == 0)
					lock = lock1;
				else
					lock = lock2;

				while (true) {
					lock.lock();
					try {
						try {
							TimeUnit.SECONDS.sleep(1);
							System.out.println(Thread.currentThread().getName() + "++获取到lock" + (r + 1) + "锁");
							TimeUnit.SECONDS.sleep(1);
						} catch (InterruptedException e) {
							e.printStackTrace();
						}
					} finally {
						lock.unlock();
					}
					try {
						TimeUnit.SECONDS.sleep(2);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
			}
		}

		for (int i = 0; i < 10; i++) {
			Worker w = new Worker();
			w.setDaemon(true);
			w.start();
		}

		for (int i = 0; i < 10; i++) {
			try {
				TimeUnit.SECONDS.sleep(1);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			System.out.println();
		}

	}

	public static void main(String[] args) {
		TestObjectLock testMyLock = new TestObjectLock();
		testMyLock.test();
	}

}