/*JAVA PROGRAM*@author : Gaurav Deshmukh* The University of Texas at Tyler* Computer Science * Assignment No: 1 * Operating Systems COSC 5330-01 * Simulation of Producer - Consumer using Semaphores*///List of various importsimport java.util.Random;import java.util.Scanner;import java.util.logging.Level;import java.util.logging.Logger;import java.util.concurrent.ArrayBlockingQueue;import java.util.concurrent.BlockingQueue;

//Main classpublic class Semsp{

//Limit for Given Buffer private int LIMIT = 80; //Queue is used as buffer private static BlockingQueue array = new ArrayBlockingQueue(80);//producer thread loop count int pc=0;//consumer thread loop count int cc=0;//randon class object for getting random values to insert in Queue Random random = new Random();// mod is the integer which will decide when to print buffer int mod;// Flag for Availabilty of items volatile boolean ITM_AVL = true; // Flag for Space Availability volatile boolean SPC_AVL = true; // Flag for Buffer Availability volatile boolean BUF_AVL = true; //No of producing units int n; //No of consuming units int m; // wait signal for flags ; in binary S=S-1; public boolean waitSem(){ return false; } // Green signal for flags; in binary S=S+1; public boolean signalSem(){ return true; }

// Gets mod for printing the buffer at right time public int getMod(){ if (n > m){ mod = n; } else{ mod = m; } return mod; }// The method for producer thread public void producer() throws InterruptedException{ while(true){//System.out.println("Producer ? Space Available :" + SPC_AVL);//checks if space available is set if(SPC_AVL){// repeat until buffer is full if (array.size()!=80){ BUF_AVL = waitSem();//System.out.println("Producer -> Buffer Available :" + BUF_AVL); ITM_AVL = waitSem(); //System.out.println("Producer -> Item Available :" + ITM_AVL);//creatiton of value int val = random.nextInt(1000);// insert value into Queue array.put(val); //System.out.print(" " + val); pc++; if (pc % getMod() == 0){ System.out.println("\tBuffer Size:" + array.size()); }// After insertion set item available ITM_AVL = signalSem(); try {//set buffer available ; as producer threads finishes if (pc % getMod() == 0) System.out.println("" + array); BUF_AVL=signalSem(); Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } } //if buffer is full; Release buffer & wait producer thread BUF_AVL = signalSem(); Thread.sleep(100);// As the program runs infinitely to hold at some point//so after 1000 iterations of threads // program will exit forcefully with exit code 1 if(pc > 1000) System.exit(1); } } }

public void consumer(){ while(true){//System.out.println("Consumer ? Item Available :" + ITM_AVL);// checks if item available is set if(ITM_AVL){ BUF_AVL=waitSem(); if(array.size()==0){ try { BUF_AVL = signalSem(); System.out.println("After Consumption:" + array); Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } } //System.out.println("Consumer -> Buffer Available :" + BUF_AVL); try{ int val;// Remove value from the buffer val = array.take(); System.out.println("Consume:" + val); } catch (InterruptedException ex) { Logger.getLogger(Semsp.class.getName()).log(Level.SEVERE,null,ex); } SPC_AVL = signalSem(); // System.out.println("Consumer -> Space Available :" + SPC_AVL); try { BUF_AVL = signalSem(); Thread.sleep(100); } catch (InterruptedException e){ e.printStackTrace(); }//if buffer is empty; Release buffer & wait consumer thread BUF_AVL = signalSem(); try { Thread.sleep(100);// As the program runs infinitely to hold program at some point// after 1000 iterations of threads // program will exit forcefully with exit code 1 if(cc > 1000) System.exit(1); } catch (InterruptedException ex) { Logger.getLogger(Semsp.class.getName()).log(Level.SEVERE,null,ex); } } } }

// Simualtion function for creating and calling threads public synchronized void simulate(){ Thread[] producerthreads = new Thread[n]; for (int i = 0; i < producerthreads.length; i++) { producerthreads[i] = new Thread(new Runnable() { @Override public void run() { try { // some code to run in parallel producer(); } catch (InterruptedException ex) { Logger.getLogger(Semsp.class.getName()).log(Level.SEVERE,null,ex); } } }); producerthreads[i].start(); } Thread[] consumerthreads = new Thread[m]; for (int i = 0; i < consumerthreads.length; i++) { consumerthreads[i] = new Thread(new Runnable() { @Override public void run() { // some code to run in parallel consumer(); } }); consumerthreads[i].start(); } try{ for(int i=0 ; i