What I want to do here is to print even numbers by even consumers, odd numbers by odd consumers.
There is an evenodd method which is basically consuming any number and printing (whether even or odd). I have got 2 even consumer threads, 2 odd consumer threads, 2 evenodd consumer threads and 3 producer threads.
I am new to the semaphores concept, and I tried using it. When I remove the evenodd method and related threads I get the correct output i.e. Even numbers by even threads and odd numbers by odd threads. But when I again put the evenodd method and evenodd threads I get a deadlock.
It would be very helpful if anyone can guide me on this, where I am going wrong and how to fix it. Please throw some light on how I can implement the evenodd method so that it would work correctly.
package lab61;
import java.util.LinkedList;
import java.util.Random;
import java.util.concurrent.Semaphore;
public class Process {
Semaphore empty;
Semaphore full;
Semaphore even;
Semaphore odd;
Semaphore mutex;
//Semaphore evenodd;
boolean evenb;
boolean oddb,eo;
LinkedList<Integer> list;
Random random;
public Process(int capacity){
list=new LinkedList<Integer>();
empty=new Semaphore(capacity);
full=new Semaphore(0,true);
mutex=new Semaphore(1,true);
even=new Semaphore(0,true);
evenb=false;
oddb=false;
eo=false;
odd=new Semaphore(0,true);
//evenodd = new Semaphore(0,true);
random=new Random();
}
public void Producer() throws InterruptedException{
while(true){
int a=random.nextInt(100);
empty.acquire();
mutex.acquire();
list.add(a);
System.out.println("Producing "+a);
System.out.println(list);
if((list.get(0)%2)==0){
if(!evenb){
even.release();
evenb = true;
}
}else if((list.get(0)%2)==1){
if(!oddb){
odd.release();
oddb = true;
}
}
/*if(((list.get(0)%2)==0)||((list.get(0)%2)==1)){
if(!eo){
evenodd.release();
eo = true;
}
}*/
mutex.release();
full.release();
}
}
public void consumereven() throws InterruptedException{
while(true){
//Thread.sleep(2000);
even.acquire();
Thread.sleep(2000);
full.acquire();
mutex.acquire();
int value = list.removeFirst();
System.out.println("I am the even consumer "+ value);
evenb = false;
System.out.println(list);
mutex.release();
empty.release();
}
}
public void consumerodd() throws InterruptedException{
while(true){
//Thread.sleep(2000);
odd.acquire();
Thread.sleep(2000);
full.acquire();
//odd.acquire();
mutex.acquire();
int value = list.removeFirst();
System.out.println("I am the odd consumer "+ value);
System.out.println(list);
oddb = false;
mutex.release();
empty.release();
}
}
public void evenodd() throws InterruptedException {
while(true){
full.acquire();
mutex.acquire();
int value = list.removeFirst();
System.out.println("i am the evenodd consumer " + value );
if((list.get(0)%2)==0){
if(oddb=true){
odd.acquire();
oddb=false;
}
if(evenb==false){
even.release();
evenb = true;
}
}
else if((list.get(0)%2)==1){
if(evenb=true){
even.acquire();
evenb=false;
}
if(oddb==false){
odd.release();
oddb = true;
}
}
System.out.println(list);
mutex.release();
empty.release();
}
}
}
package lab61;
import lab6.producer;
public class App {
public static void main(String[] args) throws InterruptedException{
Process p=new Process(10);
Thread producer1=new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
try {
p.Producer();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
Thread producer2=new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
try {
p.Producer();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
Thread producer3=new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
try {
p.Producer();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
Thread consumereven1=new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
try {
p.consumereven();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
Thread consumereven2=new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
try {
p.consumereven();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
Thread consumerodd1=new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
try {
p.consumerodd();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
Thread consumerodd2=new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
try {
p.consumerodd();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
Thread evenodd1=new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
try {
p.evenodd();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
Thread evenodd2=new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
try {
p.evenodd();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
producer1.start();
producer2.start();
producer3.start();
consumereven1.start();
consumereven2.start();
consumerodd1.start();
consumerodd2.start();
evenodd1.start();
evenodd2.start();
producer1.join();
producer2.join();
producer3.join();
consumereven1.join();
consumereven2.join();
consumerodd1.join();
consumerodd2.join();
evenodd1.join();
evenodd2.join();
}
}
