package chat.util;
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import java.util.concurrent.atomic.AtomicReference;
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public class SpinLock {
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//java中原子（CAS）操作
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AtomicReference<Thread> owner = new AtomicReference<>();//持有自旋锁的线程对象
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private int count;
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public void lock() {
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Thread cur = Thread.currentThread();
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//lock函数将owner设置为当前线程，并且预测原来的值为空。unlock函数将owner设置为null，并且预测值为当前线程。当有第二个线程调用lock操作时由于owner值不为空，导致循环
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//一直被执行，直至第一个线程调用unlock函数将owner设置为null，第二个线程才能进入临界区。
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while (!owner.compareAndSet(null, cur)){
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}
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}
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public void unLock() {
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Thread cur = Thread.currentThread();
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owner.compareAndSet(cur, null);
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}
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}
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