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社区首页 >问答首页 >java生产者消费者问题-让线程在完成之前等待其他人完成

问java生产者消费者问题-让线程在完成之前等待其他人完成
EN

Stack Overflow用户
提问于 2014-08-15 21:58:19
回答 2查看 852关注 0票数 2

我目前正在处理多个线程的生产者消费者问题。最初有1000个字节可用，使用RAM nad驱动程序占用了500个字节，留给我来处理线程的500个字节。将有4个生产者，具体如下：

  1. 启动10秒BubbleWitch2会话的线程，它需要每秒100个字节的内存。
  2. 一个线程，用于启动每秒20秒的Spotify流，它需要每秒250个字节的RAM。
  3. 系统线程和管理线程，它们一起需要每秒50字节的RAM，并在调用之后执行一段随机时间。
  4. 安装一个新的2KB安全更新程序的线程，它将被存储到磁盘中，安装时需要每秒150个字节的RAM。假设系统中有足够的磁盘容量来支持这个线程。

该程序意味着在安全更新完成后停止执行。理想情况下，这应该在不设置线程优先级的情况下实现。它以前是工作的，但现在当我运行程序时，安全线程在中间完成，spotify正在结束笑。是否有可能导致这种情况的错误？我已经在下面列出了我的代码。我还没有将所有字节大小分配给线程和缓冲区。

我的主要方法。

代码语言：javascript
复制
/**
 * Created by User on 10/08/2014.
 */
public class ProducerConsumerTest {
        public static void main(String[] args) throws InterruptedException {
            Buffer c = new Buffer();
            BubbleWitch2 p1 = new BubbleWitch2(c, 1);
            Processor c1 = new Processor(c, 2);
            Spotify p2 = new Spotify(c, 3);
            SystemManagement p3 = new SystemManagement(c,4);
            securityUpdate p4 = new securityUpdate(c,5, p1,p2,p3);

            p1.setName("BubbleWitch2 ");
            p2.setName("Spotify ");
            p3.setName("System Management ");
            p4.setName("Security Update ");

            c1.start();
            p1.start();
            p2.start();
            p3.start();
            p4.start();

            p2.join();
            p3.join();
            p4.join();
            System.exit(0);

        }
    }

我的缓冲区/库洞类

代码语言：javascript
复制
/**
 * Created by User on 10/08/2014.
 */
class Buffer {
    private int contents;
    private boolean available = false;
    public synchronized int get() {
        while (available == false) {
            try {
                wait();
            }
            catch (InterruptedException e) {
            }
        }
        available = false;
        notifyAll();
        return contents;
    }
    public synchronized void put(int value) {
        while (available == true) {
            try {
                wait();
            }
            catch (InterruptedException e) {
            }
        }
        contents = value;
        available = true;
        notifyAll();
    }
}

我的消费者课

代码语言：javascript
复制
class Processor extends Thread {
    private Buffer cubbyhole;
    private int number;
    public Processor(Buffer c, int number) {
        cubbyhole = c;
        this.number = number;
    }
    public void run() {
        int value = 0;
        for (int i = 0; i < 60; i++) {
            value = cubbyhole.get();
            System.out.println("Processor #"
                    + this.number
                    + " got: " + value);
        }
    }
}

我的spotify制片人班

代码语言：javascript
复制
class Spotify extends Thread {
    private Buffer buffer;
    private int number;
    private int bytes;

    public Spotify(Buffer c, int number) {
        buffer = c;
        this.number = number;
    }

    public void run() {
        for (int i = 0; i < 20; i++) {
            buffer.put(i);
            System.out.println(getName() + this.number
                    + " put: " + i);
            try {
                sleep(1000);
            } catch (InterruptedException e) { }
        }
        System.out.println("*****************************");
        System.out.println("Spotify has finished executing.");
        System.out.println("*****************************");

    }
}

我的泡泡剂制作课

代码语言：javascript
复制
import java.lang.*;
import java.lang.System;
/**
 * Created by User on 10/08/2014.
 */
class BubbleWitch2 extends Thread {
    private Buffer buffer;
    private int number;
    private int bytes;

    public BubbleWitch2(Buffer c, int number) {
        buffer = c;
        this.number = number;
    }

    public void run() {
        for (int i = 0; i < 10; i++) {
            buffer.put(i);
            System.out.println(getName() + this.number
                    + " put: " + i);
            try {
                sleep(1000);
            } catch (InterruptedException e) { }
        }
        System.out.println("*****************************");
        System.out.println("BubbleWitch2 has finished executing.");
        System.out.println("*****************************");
    }
}

我的系统管理制作人课程

代码语言：javascript
复制
  class SystemManagement extends Thread {
        private Buffer buffer;
        private int number, min = 1, max = 15;
        private int loopCount = (int) (Math.random() * ( max - min ));

        public SystemManagement(Buffer c, int number) {
            buffer = c;
            this.number = number;
        }

        public void run() {
            for (int i = 0; i < loopCount; i++) {
                buffer.put(i);
                System.out.println(getName() + this.number
                        + " put: " + i);
                try {
                    sleep(1000);
                } catch (InterruptedException e) { }
            }
            System.out.println("*****************************");
            System.out.println("System Management has finished executing.");
            System.out.println("*****************************");
        }
    }

我的安全更新类

代码语言：javascript
复制
/**
 * Created by User on 14/08/2014.
 */
import java.lang.*;
import java.lang.System;

/**
 * Created by User on 11/08/2014.
 */
class securityUpdate extends Thread {
    private Buffer buffer;
    private int number;
    private int bytes = 150;
    private int process = 0;

    public securityUpdate (Buffer c, int number, BubbleWitch2 bubbleWitch2, Spotify spotify, SystemManagement systemManagement) throws InterruptedException {
        buffer = c;
        this.number = number;
        bubbleWitch2.join();
        spotify.join();
        systemManagement.join();
    }

    public void run() {

        for (int i = 0; i < 10; i++) {
            buffer.put(i);
            System.out.println(getName() + this.number
                    + " put: " + i);
            try {
                sleep(1000);
            } catch (InterruptedException e) { }
        }
        System.out.println("*****************************");
        System.out.println("Security Update has finished executing.");
        System.out.println("*****************************");
    }
}

我希望它能够在没有硬编码的情况下在计数中最后运行，因为我需要在代码中计算以每秒150个字节的大小运行2000字节所需的时间，这将使硬编码变得无关紧要。有人有什么想法吗？

synchronization
producer-consumer
java
multithreading
time
EN

回答 2

Stack Overflow用户

回答已采纳

发布于 2014-08-16 05:47:10

使用executor框架尝试下面修改的代码，它更简单：-

代码语言：javascript
复制
public class ProducerConsumerTest {
    public static void main(String[] args) throws InterruptedException {
        BlockingQueue<Integer> c = new ArrayBlockingQueue<Integer>(1);
        CountDownLatch doneSignal = new CountDownLatch(3);

        Processor c1 = new Processor(c, 2, doneSignal);

        BubbleWitch2 p1 = new BubbleWitch2(c, 1, doneSignal);        
        Spotify p2 = new Spotify(c, 3, doneSignal);
        SystemManagement p3 = new SystemManagement(c,4, doneSignal);
        SecurityUpdate p4 = new SecurityUpdate(c,5, doneSignal);

        p1.setName("BubbleWitch2 ");
        p2.setName("Spotify ");
        p3.setName("System Management ");
        p4.setName("Security Update ");

        ExecutorService exec = Executors.newCachedThreadPool();
        exec.submit(c1);
        exec.submit(p1);
        exec.submit(p2);
        exec.submit(p3);        

        Future<?> securityFuture = exec.submit(p4);

        try {
            while(securityFuture.get()!=null) {

            }           
            exec.shutdown();
            while(exec.awaitTermination(1000, TimeUnit.MILLISECONDS)) {

            }
            exec.shutdownNow();
        } catch (ExecutionException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        System.exit(0);
    }
}
class Processor extends Thread {
    private BlockingQueue<Integer> cubbyhole;
    private int number;
    private CountDownLatch doneSignal;

    public Processor(BlockingQueue<Integer> c, int number,CountDownLatch doneSignal) {
        cubbyhole = c;
        this.number = number;
        this.doneSignal = doneSignal;
    }
    public void run() {
        int value = 0;
       // for (int i = 0; i < 60; i++) {
        while(true) {
            try {
                value = cubbyhole.take();
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                //e.printStackTrace();
            }
            System.out.println("Processor #"
                    + this.number
                    + " got: " + value);
        }
        //doneSignal.countDown();
    }
}

class Spotify extends Thread {
    private BlockingQueue<Integer> buffer;
    private int number;
    private int bytes;
    private CountDownLatch doneSignal;

    public Spotify(BlockingQueue<Integer> c, int number, CountDownLatch doneSignal) {
        buffer = c;
        this.number = number;
        this.doneSignal = doneSignal;
    }

    public void run() {
        for (int i = 0; i < 20; i++) {
            try {
                buffer.put(i);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            System.out.println(getName() + this.number
                    + " put: " + i);           
        }
        System.out.println("*****************************");
        System.out.println("Spotify has finished executing.");
        System.out.println("*****************************");
        doneSignal.countDown();
    }
}

class BubbleWitch2 extends Thread {
    private BlockingQueue<Integer> buffer;
    private int number;
    private int bytes;
    private CountDownLatch doneSignal;

    public BubbleWitch2(BlockingQueue<Integer> c, int number, CountDownLatch doneSignal) {
        buffer = c;
        this.number = number;
        this.doneSignal = doneSignal;
    }

    public void run() {
        for (int i = 0; i < 10; i++) {
            try {
                buffer.put(i);
            } catch (InterruptedException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
            System.out.println(getName() + this.number
                    + " put: " + i);

        }
        System.out.println("*****************************");
        System.out.println("BubbleWitch2 has finished executing.");
        System.out.println("*****************************");
        doneSignal.countDown();
    }
}

class SystemManagement extends Thread {
    private BlockingQueue<Integer> buffer;
    private int number, min = 1, max = 15;
    private int loopCount = (int) (Math.random() * ( max - min ));
    private CountDownLatch doneSignal;

    public SystemManagement(BlockingQueue<Integer> c, int number, CountDownLatch doneSignal) {
        buffer = c;
        this.number = number;
        this.doneSignal = doneSignal;
    }

    public void run() {
        for (int i = 0; i < loopCount; i++) {
            try {
                buffer.put(i);
            } catch (InterruptedException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
            System.out.println(getName() + this.number
                    + " put: " + i);

        }
        System.out.println("*****************************");
        System.out.println("System Management has finished executing.");
        System.out.println("*****************************");
        doneSignal.countDown();
    }
}

class SecurityUpdate extends Thread {
    private BlockingQueue<Integer> buffer;
    private int number;
    private int bytes = 150;
    private int process = 0;
    private CountDownLatch doneSignal;

    public SecurityUpdate (BlockingQueue<Integer> c, int number, CountDownLatch doneSignal) {
        buffer = c;
        this.number = number;
        this.doneSignal = doneSignal;
    }

    public void run() {
        try {
            doneSignal.await();         
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        for (int i = 0; i < 10; i++) {
            try {
                buffer.put(i);
            } catch (InterruptedException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
            System.out.println(getName() + this.number
                    + " put: " + i);

        }
        System.out.println("*****************************");
        System.out.println("Security Update has finished executing.");
        System.out.println("*****************************");
    }
}

如果你有什么问题，请告诉我。

票数 2
EN

Stack Overflow用户

发布于 2014-08-16 05:33:06

我不确定我是否完全理解这个问题，但是您正在加入securityUpdate的构造函数中的线程：

代码语言：javascript
复制
bubbleWitch2.join();
spotify.join();
systemManagement.join();

这些连接发生在线程启动之前，因此它们是不操作的。

同样，我在这里还没有完全理解这个问题，但似乎您正在尝试让securityUpdate等待这三个线程的完成。如果是这样的话，您可能希望将对join()的调用移到run()方法中。

或者类似的东西。祝好运。

票数 2
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：

https://stackoverflow.com/questions/25334793

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