package bunny.thread;

import java.util.concurrent.locks.ReentrantLock;

public class ThreadTest3 {
    private static int count = 0;
    private static Integer threadCount = 0;
    private static Integer lockCount = 0;
    private static Integer lockReentrantLockCount = 0;
    private static final Object lockObject = new Object();
    private static final ReentrantLock lock = new ReentrantLock();

    /**
     * * 资源竞争代码示例
     */
    public static void main(String[] args) {
        // 这是单线程下没有竞争的示例
        for (int i = 0; i < 10; i++) {
            for (int j = 0; j < 1000; j++) {
                count++;
            }
        }

        // 有资源竞争，值不确定是多少，每一次运行都不一样
        for (int i = 0; i < 10; i++) {
            new Thread(() -> {
                for (int j = 0; j < 1000; j++) {
                    threadCount++;
                }
            }).start();
        }

        // 使用对象锁解决这个问题
        for (int i = 0; i < 10; i++) {
            new Thread(() -> {
                synchronized (lockObject) {
                    for (int j = 0; j < 1000; j++) {
                        lockCount++;
                    }
                }
            }).start();
        }

        // 使用锁解决
        for (int i = 0; i < 10; i++) {
            new Thread(() -> {
                lock.lock();
                try {
                    for (int j = 0; j < 1000; j++) {
                        lockReentrantLockCount++;
                    }
                } finally {
                    lock.unlock();
                }
            }).start();
        }
        
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            System.out.println(e.getMessage());
        }
        System.out.println("count 值：" + count);
        System.out.println("threadCount 值：" + threadCount);
        System.out.println("lockCount 值：" + lockCount);
        System.out.println("lockReentrantLockCount 值：" + lockReentrantLockCount);
    }
}