java - 在并发类的 run() 方法中放置什么？

Question

假设我们有一个名为 Teacher 的线程安全类，它实现了 Runnable。教师可以阅读或写入学生的书本。

public class Teacher implements Runnable {

boolean doneWithBook = false;
private Lock lock = new ReentrantLock();
private Condition cond = lock.newCondition();

public void readBook(Book book) {

    lock.lock();
    try {
        book.read();
        doneWithBook = false;
        cond.signalAll();
        System.out.println("Teacher read the book");
    } finally {
        lock.unlock();
    }
}

public void writeToBook(Book book) {

    lock.lock();
    try {
        book.write();
        doneWithBook = true;
        System.out.println("Teacher wrote to book.");
    } finally {
        lock.unlock();
    }
}

Teacher 实现了 Runnable，因此任务可以在其自己的单独线程上运行。我不明白的是要在 Runnable 的接口(interface) run() 方法中放入什么。如果我想读/写这本书怎么办？ run() 如何发挥作用？非常感谢示例。

@Override
public void run() {

  // now what???

}

Answer 1

好的，一般而言，您的任务实现了Runnable，因此在您的情况下，您可能会遇到以下情况:

public ReadTask implements Runnable
{
  private Teacher teacher;

  public ReadTask(Teacher teacher)
  {
    this.teacher = teacher;
  }

  public void run()
  {
    teacher.readBook();
  }
}

public WriteTask implements Runnable
{
  private Teacher teacher;

  public WriteTask (Teacher teacher)
  {
    this.teacher = teacher;
  }

  public void run()
  {
    teacher.writeToBook();
  }
}

然后你的调用代码将如下所示:

Teacher teacher = ...
new Thread(new ReadTask(teacher)).start();
new Thread(new WriteTask(teacher)).start();

另请注意，代码中的条件并没有真正实现任何目标。