如何在不同的线程中做不同的事情？

Question

I have made a program that computes the sum, difference, product and quotient of two numbers. I used threads to do this as follows

import java.util.Scanner;

public class ThreadTest
{
    public static void main(String args[])
    {

        Scanner kb = new Scanner(System.in);

        System.out.print("Enter 1st operand ::");
        int a = kb.nextInt();
        System.out.print("Enter 2nd operand ::");
        int b = kb.nextInt();

        Addition add = new Addition(a, b);
        Subtraction sub = new Subtraction(a, b);
        Multiplication mul = new Multiplication(a, b);
        Division div = new Division(a, b);

        Thread t1 = new Thread(add);
        Thread t2 = new Thread(sub);
        Thread t3 = new Thread(mul);
        Thread t4 = new Thread(div);

        t1.start();
        t2.start();
        t3.start();
        t4.start();
    }
}

class Addition implements Runnable
{
    int a, b;
    public Addition(int a, int b)
    {
        this.a = a;
        this.b = b;
    }
    public void run()
    {
        System.out.println("Addition :: " + (a+b));
    }
}


class Subtraction implements Runnable
{
    int a, b;
    public Subtraction(int a, int b)
    {
        this.a = a;
        this.b = b;
    }
    public void run()
    {
        System.out.println("Subtraction :: " + (a-b));
    }
}

class Multiplication implements Runnable
{
    int a, b;
    public Multiplication(int a, int b)
    {
        this.a = a;
        this.b = b;
    }
    public void run()
    {
        System.out.println("Multiplication :: " + (a*b));
    }
}

class Division implements Runnable
{
    int a, b;
    public Division(int a, int b)
    {
        this.a = a;
        this.b = b;
    }
    public void run()
    {
        System.out.println("Division :: " + (float)(a/b));
    }
}

Now what I want to know is that I needed to make a separate class for every operation I wanted to run in a separate thread so is there a way I can do it in one class and still have separate threads for every operator?

Edit 1 Pseudocode:

class operators implements runnable{
     public void run1(){
     //some thing to do
     }
     public void run2(){
     //some thing to do
     }
}
public class Main{
    public static void main(String args[]){
    //make object of operator class
    //make new thread for operator class' object
    //thread.start() should start all the run(run1, run2) methods at once
}

Basically, what I want is one class to have all the run functions(or whatever they are called) so it becomes less of a code to write and easier to start the threads.

Any help is highly appreciated.

Regards

Pranav Rastogi

Answer 1

With your pseudocode, you can use inner classes implementing Runnable. One Runnable for each task.

 Runnable add = new Runnable() {
          public void run() {
              System.out.println("Addition :: " + (a+b));
          };
    };   

And use a main Runnable to start the global tasks. This will be your resulting class. I guess the future use will be more complex

import java.util.Scanner;

public class ThreadTest
{
    public static void main(String args[])
    {

        Scanner kb = new Scanner(System.in);

        System.out.print("Enter 1st operand ::");
        int a = kb.nextInt();
        System.out.print("Enter 2nd operand ::");
        int b = kb.nextInt();

        Operations op = new Operations (a,b);

        Thread t1 = new Thread(op);

        t1.start();

    }
}

class Operations implements Runnable{
    int a, b;
    public Operations(int a, int b){
         this.a = a;
         this.b = b;
    }
    public void run() {
        Runnable add = new Runnable() {
              public void run() {
                  System.out.println("Addition :: " + (a+b));
              };
        };    

        Runnable sub = new Runnable() {
              public void run() {
                  System.out.println("Subtraction :: " + (a-b));
              };
        };

        Runnable div = new Runnable() {
              public void run() {
                  System.out.println("Division :: " + (float)(a/b));
              };
        };

        Runnable mul = new Runnable() {
              public void run() {
                  System.out.println("Multiplication :: " + (a*b));
              };
        };

        Thread t1 = new Thread(add);
        Thread t2 = new Thread(sub);
        Thread t3 = new Thread(mul);
        Thread t4 = new Thread(div);

            t1.start();
            t2.start();
            t3.start();
            t4.start();
    }

}