How can I kill all Threads of the same class from within the run() method?

Question

Ok
I have a class called Consumer that extends Thread
I have several Consumer threans running... but, when a certain condition is true (within the run() method) in ANY of the threads, I want to kill ALL the threads of that object.
is this possible?

Answer 1

I know this is gonna be too demanding, but can someone please tell me why my Consumer's run() method never reaches the System.out.println( "ALL CONSUMING DONE") line
Create a multi-threaded prime number calculator that is based on the producer-consumer model
using semaphores. Your program should be able to check for prime numbers in a range specified
by the user and with a variable number of threads. Example:
$ java PrimeFind 3 5000 10000
should use 1 producer and 2 consumers (3 threads in total, obviously the minimum is 2) to find all
the prime numbers in the range [5000,10000].
The producer should: use a buffer to store candidate numbers that have to be checked for
primality.
Consumers should: read from the buffer, check if a number is prime and update the status of the
program accordingly (e.g. show the number on the screen, or save it to a file)
import java.util.concurrent.Semaphore;
import java.io.*;
public class Assign1 {
static int fromThisNumber;
static int toThisNumber;
static int numberOfThreads;
static int buffer[];
static Semaphore ready;          /*This semaphore is used by the Producer to signal
                                     an "OK" to the consumers*/
static Semaphore critical;  /*This is a Mutex semaphore. It allows only 1 consumer
                                     to enter his critical section.
static Semaphore counter;     /*This semaphore acts as a counter.
                                    Instead of having a global variable
                                     incremented each time, we just release()
                                     this semephore when we find a prime number
                                     Because remember that release() increments permits
static Producer prod;
static Consumer cons[];
static int in=0;
static int out=0;
static PrintWriter outFile;
     public static void main (String args[]){
          try{
               outFile=new PrintWriter(new FileWriter("primes.txt"));
               }catch(Exception e){}
          numberOfThreads=Integer.parseInt(args[0]);
          fromThisNumber=Integer.parseInt(args[1]);
          toThisNumber=Integer.parseInt(args[2]);
          buffer=new int[Integer.parseInt(args[2])-Integer.parseInt(args[1])+1];
          ready=new Semaphore(0,false); /*We initialise it to 0 because we wait
                                                  for the Producer to produce atleast a
                                                  item. Suppose ready was 1 and if
                                                  Consumer ran first he would be in an
                                                  empty buffer */
          critical=new Semaphore (1,false);/*We initialise it to 1 because when
                                                     the first Consumer thread tries
                                                     to enter its critical section, it
                                                     should be allowed to;
                                                     Subsequent threads will have to
                                                     wait since only 1 thread can
                                                     access its critical section at a time*/
          counter=new Semaphore(0,false); // duh!
          cons=new Consumer[numberOfThreads-1]; /*numberOfThreads-1 because 1 thread
                                                            is taken by the Producer*/
          //Creating Producer object
          prod=new Producer();
          //Creating the Consumer object and start the thread.
          for(int i=0;i<cons.length;i++)
                    cons=new Consumer();
                    cons[i].start();
          prod.start();          
          //Printing to screen and file
/*          for(int i=0;i<buffer.length;i++)
               if(buffer[i]!=0)
                         System.out.println(buffer[i]);
                         outFile.println(buffer[i]);
          System.out.println("Total primes found between "+args[1]+" and "+toThisNumber+": "+counter.availablePermits()+"\n primes.txt written");
          outFile.println("Total primes found between "+args[1]+" and "+toThisNumber+": "+counter.availablePermits());
          outFile.close();*/                    
static class Producer extends Thread {
     public void run(){try{
          while(in<buffer.length)     /*'in' should always be more than 'out'.Oherwise the consumer will try to access an empty index*/
               {     System.out.println("producing");     
                    buffer[in]=fromThisNumber;
                    in++;
                    fromThisNumber++;
                    ready.release();
          catch (Exception e){e.printStackTrace();}
          System.out.println("ALL PRODUCING DONE");
static class Consumer extends Thread {
     int tempout=0;
     public void run(){try{
          System.out.println("before while"+this.getId());
          while(tempout<=in)
               System.out.println("before ready"+this.getId()+" "+ready.availablePermits()+" "+in);
               ready.acquire();
               System.out.println("before critical.acquire"+this.getId());
               critical.acquire();
               tempout=out;
               out++;
               critical.release();               
               if(!isPrime(buffer[tempout]))
                    {System.out.println(buffer[tempout]+" by "+this.getId());buffer[tempout]=0;}
               else {counter.release();System.out.println("prime added: "+buffer[tempout]+" by "+this.getId());}
               critical.acquire();
               tempout=out;
               System.out.println("tempout:"+tempout+" of "+this.getId());
               critical.release();
          System.out.println("ALL CONSUMING DONE"+this.getId());
     catch(Exception e){e.printStackTrace();}
     //Prime number-checking method     
     public boolean isPrime(int n){
          for(int i=2;i<=(n/2);i++)
               if(n%i==0)
                    return false;
          return true;
======================
import java.util.concurrent.Semaphore;
import java.io.*;
/* 3 questions to ask Barlas
* Why error if I start the Consumer threads before Producer
* Why does the counter semaphore always give a +1 result at the end
* Is there a way I can verify that all the work is not being done by only 1 consumer thread? In other words, the workload is being shared properly
* if I put ready.acquire() outside or inside the while loop, its not making any difference, why?
* Strangely, its not making any difference if I playing with the release() and aquire() of the semaphores, WHY?!?!
public class Assign1 {
static int fromThisNumber;
static int toThisNumber;
static int numberOfThreads;
static int buffer[];
static Semaphore ready;          /*This semaphore is used by the Producer to signal
                                   an "OK" to the consumers*/
static Semaphore critical; /*This is a Mutex semaphore. It allows only 1 consumer
                                   to enter his critical section.
static Semaphore counter;     /*This semaphore acts as a counter.
                              Instead of having a global variable
                                   incremented each time, we just release()
                                   this semephore when we find a prime number
                                   Because remember that release() increments permits
static Producer prod;
static Consumer cons[];
static int in=0;
static int out=0;
static PrintWriter outFile;
     public static void main (String args[]){
          try{
               outFile=new PrintWriter(new FileWriter("primes.txt"));
               }catch(Exception e){}
          numberOfThreads=Integer.parseInt(args[0]);
          fromThisNumber=Integer.parseInt(args[1]);
          toThisNumber=Integer.parseInt(args[2]);
          buffer=new int[Integer.parseInt(args[2])-Integer.parseInt(args[1])+1];
          ready=new Semaphore(0,false); /*We initialise it to 0 because we wait
                                                  for the Producer to produce atleast a
                                                  item. Suppose ready was 1 and if
                                                  Consumer ran first he would be in an
                                                  empty buffer */
          critical=new Semaphore (1,false);/*We initialise it to 1 because when
                                                  the first Consumer thread tries
                                                  to enter its critical section, it
                                                  should be allowed to;
                                                  Subsequent threads will have to
                                                  wait since only 1 thread can
                                                  access its critical section at a time*/
          counter=new Semaphore(0,false); // duh!
          cons=new Consumer[numberOfThreads-1]; /*numberOfThreads-1 because 1 thread
                                                            is taken by the Producer*/
          //Creating Producer object
          prod=new Producer();
          //Creating the Consumer object and start the thread.
          for(int i=0;i<cons.length;i++)
                    cons[i]=new Consumer();
                    cons[i].start();
          prod.start();          
          //Printing to screen and file
/*          for(int i=0;i<buffer.length;i++)
               if(buffer[i]!=0)
                         System.out.println(buffer[i]);
                         outFile.println(buffer[i]);
          System.out.println("Total primes found between "+args[1]+" and "+toThisNumber+": "+counter.availablePermits()+"\n primes.txt written");
          outFile.println("Total primes found between "+args[1]+" and "+toThisNumber+": "+counter.availablePermits());
          outFile.close();*/                    
static class Producer extends Thread {
     public void run(){try{
          while(in<buffer.length)     /*'in' should always be more than 'out'.Oherwise the consumer will try to access an empty index*/
               {     System.out.println("producing");     
                    buffer[in]=fromThisNumber;
                    in++;
                    fromThisNumber++;
                    ready.release();
          catch (Exception e){e.printStackTrace();}
          System.out.println("ALL PRODUCING DONE");
static class Consumer extends Thread {
     int tempout=0;
     public void run(){try{
          System.out.println("before while"+this.getId());
          while(tempout<=in)
               System.out.println("before ready"+this.getId()+" "+ready.availablePermits()+" "+in);
               ready.acquire();
               System.out.println("before critical.acquire"+this.getId());
               critical.acquire();
               tempout=out;
               out++;
               critical.release();               
               if(!isPrime(buffer[tempout]))
                    {System.out.println(buffer[tempout]+" by "+this.getId());buffer[tempout]=0;}
               else {counter.release();System.out.println("prime added: "+buffer[tempout]+" by "+this.getId());}
               critical.acquire();
               tempout=out;
               System.out.println("tempout:"+tempout+" of "+this.getId());
               critical.release();
          System.out.println("ALL CONSUMING DONE"+this.getId());
     catch(Exception e){e.printStackTrace();}
     //Prime number-checking method     
     public boolean isPrime(int n){
          for(int i=2;i<=(n/2);i++)
               if(n%i==0)
                    return false;
          return true;
===========================
BTW, when I tried to change extends Thread to implements Runnable I got some kinda of error.
Actually, my program is pretty complete... its just that something if messed up in my Consumer's run() method's while loop... I think
I know guys its crazy to ask ya'll to look at so much code, but.... I'd really appreciate it. This assignment is killing me, been at it since 10 hours now....