Hướng dẫn chữa bài tập

MultiThread - Synchronized trong Java - Đồng bộ 3 threads - Sinh số ngẫu nhiên, bình phương, và chia hết

/*
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package java2.lession5.bt02;

/**
 *
 * @author Diep.Tran
 */
public class SharedData {
    int rad;
    int total;
    //index = 1, 2, 3
    //1 => Thread 1
    //2 => Thread 2
    //3 => Thread 3
    int index;
    
    public SharedData() {
        total = 0;
        index = 1;
    }

    public int getRad() {
        return rad;
    }

    public void setRad(int rad) {
        this.rad = rad;
    }

    public int getTotal() {
        return total;
    }

    public void setTotal(int total) {
        this.total = total;
    }
    
    public synchronized void plus(int value) {
        total += value;
    }
    
    public synchronized boolean checkAvaiable() {
        return total < 2000;
    }

    public int getIndex() {
        return index;
    }

    public void setIndex(int index) {
        this.index = index;
    }
}

/*
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package java2.lession5.bt02;

import java.util.Random;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author Diep.Tran
 */
public class Thread1 extends Thread{
    SharedData sharedData;

    public Thread1(SharedData sharedData) {
        this.sharedData = sharedData;
    }

    @Override
    public void run() {
        try {
            Thread.sleep(200);
        } catch (InterruptedException ex) {
            Logger.getLogger(Thread1.class.getName()).log(Level.SEVERE, null, ex);
        }
        
        Random random = new Random();
        
        while(sharedData.checkAvaiable()) {
            synchronized(sharedData) {
                int rad = random.nextInt(100) + 1;
                sharedData.setRad(rad);
                sharedData.plus(rad);
                System.out.println("T1 >> " + rad);
                
                //thiet lap luong tiep theo dc phep chay
                if(rad % 3 == 0) {
                    sharedData.setIndex(2);
                } else {
                    sharedData.setIndex(3);
                }
                
                //sync thread
                sharedData.notifyAll();
                try {
                    sharedData.wait();
                } catch (InterruptedException ex) {
                    Logger.getLogger(Thread1.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        }
        System.out.println("T1 Stop");
        synchronized(sharedData) {
            sharedData.notifyAll();
        }
    }
}

/*
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package java2.lession5.bt02;

import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author Diep.Tran
 */
public class Thread2 extends Thread{
    SharedData sharedData;

    public Thread2(SharedData sharedData) {
        this.sharedData = sharedData;
    }

    @Override
    public void run() {
        while (sharedData.checkAvaiable()) {
            synchronized(sharedData) {
                sharedData.notifyAll();
                try {
                    while(sharedData.getIndex() != 2 && sharedData.checkAvaiable()) {
                        sharedData.wait();
                    }
                } catch (InterruptedException ex) {
                    Logger.getLogger(Thread2.class.getName()).log(Level.SEVERE, null, ex);
                }

                int rad = sharedData.getRad();
                if(rad % 3 == 0) {
                    rad *=rad;
                    System.out.println("T2 >> " + rad);
                }
                
                sharedData.setIndex(1);
            }
        }
        System.out.println("T2 Stop");
        synchronized(sharedData) {
            sharedData.notifyAll();
        }
    }
}

/*
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package java2.lession5.bt02;

import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author Diep.Tran
 */
public class Thread3 extends Thread{
    SharedData sharedData;

    public Thread3(SharedData sharedData) {
        this.sharedData = sharedData;
    }

    @Override
    public void run() {
        while (sharedData.checkAvaiable()) {
            synchronized(sharedData) {
                sharedData.notifyAll();
                try {
                    while(sharedData.getIndex() != 3 && sharedData.checkAvaiable()) {
                        sharedData.wait();
                    }
                } catch (InterruptedException ex) {
                    Logger.getLogger(Thread3.class.getName()).log(Level.SEVERE, null, ex);
                }

                int rad = sharedData.getRad();
                if(rad % 2 == 0) {
                    if(rad % 4 == 0) {
                        System.out.println("So ngau nhien chia het cho 4");
                    } else {
                        System.out.println("So ngau nhieu ko chia het cho 4");
                    }
                } else {
                    System.out.println("Ko le");
                }
                sharedData.setIndex(1);
            }
        }
        System.out.println("T3 Stop");
        synchronized(sharedData) {
            sharedData.notifyAll();
        }
    }
}

/*
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package java2.lession5.bt02;

/**
 *
 * @author Diep.Tran
 */
public class Main {
    public static void main(String[] args) {
        SharedData sharedData = new SharedData();
        
        Thread1 t1 = new Thread1(sharedData);
        Thread2 t2 = new Thread2(sharedData);
        Thread3 t3 = new Thread3(sharedData);
        
        t1.start();
        t2.start();
        t3.start();
    }
}