Utilizing the Java Programs below,

Recall that to solve a readers/writers problem (Operating Systems), create a multi-thread program to simulate the problem. The following conditions must be satisfied:

1. Any number of readers may simultaneously read the file.

2. Only one writer at a time may write to the file.

3. If a writer is writing to the file, no reader may read it.

Please use semaphore to implement mutual exclusion. Please also create some-sort of GUI Interface to choose between Readers having priority or Writers having priority.

Programs:

import java.util.concurrent.Semaphore; //Solving the mutual exclusion problem using Semaphore class class Process2 extends Thread { private int id; private Semaphore sem; public Process2(int i, Semaphore s) { id = i; sem = s; } private int random(int n) { return (int) Math.round(n * Math.random() - 0.5); } private void busy() { try { sleep(random(500)); } catch (InterruptedException e) { } } private void noncritical() { System.out.println("Thread " + id + " is NON critical"); busy(); } private void critical() { System.out.println("Thread " + id + " entering critical section"); busy(); System.out.println("Thread " + id + " leaving critical section"); } public void run() { for (int i = 0; i < 2; ++i) { noncritical(); try { sem.acquire(); } catch (InterruptedException e) { // ... } critical(); sem.release(); } } public static void main(String[] args) { final int N = 4; System.out.println("Busy waiting..."); //Semaphore(int permits, boolean fair) Semaphore sem = new Semaphore(1, true); Process2 p[] = new Process2[N]; for (int i = 0; i < N; i++) { p[i] = new Process2(i, sem); p[i].start(); } } } 

class TwoThreadsTest { public static void main (String[] args) { new SimpleThread("Jamaica").start(); new SimpleThread("Fiji").start(); } }

class SimpleThread extends Thread { public SimpleThread(String str) { super(str); } public void run() { for (int i = 0; i < 10; i++) { System.out.println(i + " " + getName()); try { sleep((int)(Math.random() * 1000)); } catch (InterruptedException e) {} } System.out.println("DONE! " + getName()); } }