我编写了一个示例程序来演示我的问题。有一个调酒师线程和三个客户线程。它们在创建后同时运行。调酒师应该为每位顾客提供一杯饮料。
我的问题是调酒师类 run() 方法中的 wait() 方法永远不会唤醒。我原本打算让每个 Customer 类的 run() 方法中的 release() 方法唤醒它，但它似乎不起作用。它永远不会醒来。
我该如何解决这个问题？感谢任何可以提供建议或代码片段的人。
import java.util.concurrent.Semaphore;
import java.util.logging.Level;
import java.util.logging.Logger;
public class Bar {
Semaphore serving;
boolean isServing = false;
public static void main(String[] args) {
Bar bar = new Bar();
bar.run();
}
public void run() {
serving = new Semaphore(1);
Thread bartender = new Thread(new Bartender());
bartender.start();
threadSleep(1000);
Thread customer1 = new Thread(new Customer());
customer1.start();
threadSleep(2000);
Thread customer2 = new Thread(new Customer());
customer2.start();
threadSleep(2000);
Thread customer3 = new Thread(new Customer());
customer3.start();
}
public void threadSleep(int time) {
try {
Thread.sleep(time);
} catch (InterruptedException ex) {
Logger.getLogger(Bar.class.getName()).log(Level.SEVERE, null, ex);
}
}
public class Bartender implements Runnable {
public void run() {
while (true) {
if (serving.availablePermits() == 0) {
synchronized (this) {
try {
System.out.println("Waiting for Customer notify");
wait();
System.out.println("Serve drink");
} catch (InterruptedException ex) {
Logger.getLogger(Bar.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
}
}
public class Customer implements Runnable {
private boolean customerServed = false;
public void run() {
if (!customerServed) {
synchronized (this) {
try {
serving.acquire();
if (serving.availablePermits() == 0 && !serving.hasQueuedThreads()) {
notify();
isServing = true;
System.out.println("Customer: Recieves drink");
customerServed = true;
serving.release();
isServing = false;
}
} catch (InterruptedException ex) {
Logger.getLogger(Bar.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
}
}