[問題] 多執行續的消費者和生產者

[obelisk0114 (追風箏的孩子)]

生產者每秒可以生產一樣產品 (product),

消費者每秒消費 0, 1, 2..., m 樣產品 (order)

若生產者來不及生產, 消費者必須等待

消費者一次買完所需, 除非產品不夠 (process)

ex1: 產品 4, 消費 2 => 產品 2

ex2: T1 消費 2
     T2 產品 1, 完成 1
     T2 產品 1, 完成 1
     T1 消費 1 (新的)
     T2 產品 1, 完成 1 (處理新的 T1)

我需要列印前 n 秒結果

主要程式1 Clerk

private int product = 0;
private int order = 0;
private int process = 0;

// Manufacture
public synchronized void setProduct() {
    product++;
    process = Math.min(product, order);
    order -= process;
    System.out.printf("%d car available, %d requests processed!\n",
product, process);
    product -= process;

    if (order == 0) {
        notify();
    }

    n--;
    if (n == 0) {        // 感覺是不好的寫法
        System.exit(0);
    }
}

// Consumer
public synchronized void getProduct(int size) {
    System.out.printf("%d orders received\n", size);
    order = size;
    if (product + 1 < size) {
        try {
            wait();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

主要程式2 Consumer

private Clerk clerk;

public Consumer(Clerk clerk) {
    this.clerk = clerk;
}

public void run() {
    System.out.println("ready to take orders..");

    for (int i = 1; i <= n; i++) {
        try {
            Thread.sleep(1000);
        }
        catch(InterruptedException e) {
            e.printStackTrace();
        }

        int size = (int) (Math.random() * (m + 1));
        clerk.getProduct(size);
    }
}

主要程式3 Manufacture

private Clerk clerk;

public Manufacture(Clerk clerk) {
    this.clerk = clerk;
}

public void run() {
    System.out.println("ready to manufacture cars..");

    for (int i = 1; i <= n; i++) {
        try {
            Thread.sleep(1000);
        }
        catch(InterruptedException e) {
            e.printStackTrace();
        }

        clerk.setProduct();
    }
}

Bug:

有時會產生奇怪的結果,下面是其中一次的結果

ready to take orders..
ready to manufacture cars..
1 orders received
1 car available, 1 requests processed!
1 car available, 0 requests processed! (應該要先 orders)
0 orders received
2 car available, 0 requests processed!
0 orders received
3 car available, 0 requests processed!
2 orders received
4 car available, 2 requests processed!
0 orders received
3 car available, 0 requests processed!
0 orders received
4 car available, 0 requests processed!
0 orders received
5 car available, 0 requests processed!
1 orders received
2 orders received
6 car available, 2 requests processed! (順序又反轉了)
5 car available, 0 requests processed!

請各位大大看看要如何修改

謝謝

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推 swpoker: 程式進入點勒，main?要貼完整程式碼好嗎
public class Sales {

    public static void main(String[] args) {
        Clerk clerk = new Clerk();

        // Consumer
        Thread consumerThread = new Thread(new Consumer(clerk));

        // Manufacture
        Thread producerThread = new Thread(new Manufacture(clerk));

        consumerThread.start();
        producerThread.start();

    }

}
※ 編輯: obelisk0114 (47.148.240.220), 10/14/2018 08:58:42
推 swpoker: order檢查要放在前面啊
將 Clerk 的 setProduct 改成以下

public synchronized void setProduct() {
    if (order == 0) {
        notify();
    }

    product++;
    process = Math.min(product, order);
    order -= process;
    System.out.printf("%d car available, %d requests processed!\n",
product, process);
    product -= process;

    n--;
    if (n == 0) {
        System.exit(0);
    }
}

也會出現下面

ready to take orders..
ready to manufacture cars..
1 car available, 0 requests processed!
1 orders received
2 car available, 1 requests processed!
2 orders received
2 car available, 2 requests processed!
1 orders received
1 car available, 1 requests processed!
2 orders received
1 car available, 1 requests processed!
1 car available, 1 requests processed!
1 car available, 0 requests processed!
2 car available, 0 requests processed!
2 orders received
1 orders received
3 car available, 1 requests processed!
3 car available, 0 requests processed!
※ 編輯: obelisk0114 (47.148.240.220), 10/14/2018 17:04:12
→ zop: 我的話，只會設計跑一個生產者的thread，每秒生產之後去檢查
→ zop: 消費者最早未結的需求，數量符合就結單，一直到數量不符，並
→ zop: 且產生一個新的需求。
→ obelisk0114: 消費者消費數量是隨機的, 兩者每秒都在行動
→ obelisk0114: 只是生產的產品不夠多, 消費者就需要等待
→ zop: 製造跟購買中間，其實要多一個負責販賣的
→ obelisk0114: Clerk 程式是負責販賣, 我覺得問題應該在它那邊
用 BlockingQueue 可以得到結果, 但是只會有 Consumer 在 print

manufacture 只管生產,不去 print

這樣應該不算兩個 thread 都有 print ?
※ 編輯: obelisk0114 (47.148.240.220), 10/19/2018 14:33:48