Question & Answer: Modify the following code using multi-threading Java implementation of the system……

Modify the following code using multi-threading Java implementation of the system.

At the minimum:

a. Each station should be implemented using a dedicated thread

b. The simulation control should be implemented using a dedicated thread.

c. The carrier should be a shared resource (as the bounded Q in the threads example).

d. Threads should have provisions for synchronization, avoidance of race conditions and deadlocks.

e. Threads cannot communicate with a other threads via inter-process communication (except for using locks and synch.)

The program should use the following class diagram.



//CSMACD Class
import java.util.Random;
public class CSMACD
{

    static boolean randomBool()
    {
        Random ran=new Random();
        int num=ran.nextInt();
        return num%2==1;
    }
    public static void main(String[] args)
    {
        Station s1,s2,s3;
        double r1, r2 , r3, r4;
        boolean carrierStatus;

        for(int i = 0; i<1500; i++)  
        {
            for(int j = 0; j<3; j++)  
            {
                carrierStatus = randomBool();  
                r1 = Math.random();  
                s1 = new Station((int) r1,carrierStatus);

                carrierStatus = randomBool();
                r1=Math.random();  
                s2=new Station((int) r1,carrierStatus);

                carrierStatus = randomBool();
                r1=Math.random();  
                s3=new Station((int) r1,carrierStatus);

                System.out.println("sending message from s1 to s2");



                 if(s1.isCarrierStatus() && s2.isCarrierStatus())
                {
                    System.out.println("Collision occur! Transmiss stop!");
                    r4 = Math.random();
                    try
                    {
                        Thread.sleep((long) r4);
                    }
                    catch (InterruptedException e)
                    {
                        e.printStackTrace();
                    }
                }

                else if(s1.isCarrierStatus()==false&&s2.isCarrierStatus()==false)
                {
                    r2=Math.random();
                    s2.setMessage((int) r2);
                    System.out.println("Data has been transmited successfully!");
                }

                else
                {
                    System.out.println("s1 or s2 is looking busy!");
                    r3=Math.random();
                    try
                    {
                        Thread.sleep((long) r3);
                    }
                    catch (InterruptedException e)
                    {
                        e.printStackTrace();
                    }
                }
                System.out.println("sending message from s2 to s3");



                if(s2.isCarrierStatus()&&s3.isCarrierStatus())
                {
                    System.out.println("Collision occur! Transmiss stop!");
                    r4 = Math.random();
                    try
                    {
                        Thread.sleep((long) r4);
                    }
                    catch (InterruptedException e)
                    {
                        e.printStackTrace();
                    }
                }
                else if(s2.isCarrierStatus()==false&&s3.isCarrierStatus()==false)

                {
                    r2=Math.random();
                    s3.setMessage((int) r2);
                    System.out.println("Data has been transmited successfully!");
                }
                else
                {
                    System.out.println("s2 or s3 is looking busy!");
                    r3=Math.random();
                    try
                    {
                        Thread.sleep((long) r3);
                    }
                    catch (InterruptedException e)
                    {
                        e.printStackTrace();
                    }
                }

                System.out.println("sending message from s3 to s1");



                if(s3.isCarrierStatus()&&s1.isCarrierStatus())
                {
                    System.out.println("Collision occur! Transmiss stop!");
                    r4=Math.random();
                    try
                    {
                        Thread.sleep((long) r4);
                    }
                    catch (InterruptedException e)
                    {
                        e.printStackTrace();
                    }
                }

                else if(s3.isCarrierStatus()==false&&s1.isCarrierStatus()==false)
                {
                    r2=Math.random();
                    s1.setMessage((int) r2);
                    System.out.println("Data has been transmited successfully!");
                }
                else
                {
                    System.out.println("s3 or s1 is looking busy!");
                    r3=Math.random();
                    try
                    {
                        Thread.sleep((long) r3);
                    }
                    catch (InterruptedException e)
                    {
                        e.printStackTrace();
                    }
                }
            }
        }
    }
}



//Station Class

public class Station
{
    private int message;
    private boolean carrierStatus;
    private int reveivedMessage;
    public Station(int message, boolean carrierStatus)
    {
        this.message = message;
        this.carrierStatus = carrierStatus;
    }

    public int getMessage()
    {
        return message;
    }

    public void setMessage(int message)
    {
        this.message = message;
    }

    public boolean isCarrierStatus()
    {
        return carrierStatus;
    }

    public void setCarrierStatus(boolean carrierStatus)
    {
        this.carrierStatus = carrierStatus;
    }

    public int getReveivedMessage()
    {
        return reveivedMessage;
    }

    public void setReveivedMessage(int reveivedMessage)
    {
        this.reveivedMessage = reveivedMessage;
    }
}