JavaLangAccess.blockedOn（线程t，可中断的b）做什么？

Question

来自public javadoc：

void blockedOn(Thread t, Interruptible b)

     

设置线程的阻止字段。

我在java nio研究期间使用该方法进行了堆栈，特别是AbstractInterruptibleChannel源代码

Answer 1

如果查看OpenJDK，则调用

/* The object in which this thread is blocked in an interruptible I/O
 * operation, if any.  The blocker's interrupt method should be invoked
 * after setting this thread's interrupt status.
 */
private volatile Interruptible blocker;
private Object blockerLock = new Object();

/* Set the blocker field; invoked via sun.misc.SharedSecrets from java.nio code
 */
void blockedOn(Interruptible b) {
synchronized (blockerLock) {
    blocker = b;
}
}

这用于在线程中断时触发操作。

Answer 2

好像，我确实在java.lang.Thread源代码（Oracle / Sun JVM）中找到了答案：

/* The object in which this thread is blocked in an interruptible I/O
 * operation, if any.  The blocker's interrupt method should be invoked
 * after setting this thread's interrupt status.
 */
private volatile Interruptible blocker;
private Object blockerLock = new Object();

/* Set the blocker field; invoked via sun.misc.SharedSecrets from java.nio code
 */
void blockedOn(Interruptible b) {
    synchronized (blockerLock) {
         blocker = b;
    }
}
public void interrupt() {
    if (this != Thread.currentThread())
        checkAccess();

    synchronized (blockerLock) {
        Interruptible b = blocker;
        if (b != null) {
        interrupt0();        // Just to set the interrupt flag
        b.interrupt();
        return;
        }
    }
    interrupt0();
}

如果我错了，请纠正我，我的结论是：

• Interruptible只是线程中断事件的回调
• 只能使用以下代码将具体的可中断实例附加到具体类：sun.misc.SharedSecrets.getJavaLangAccess（）。blockedOn（threadInstance，intrInstance）;