Threads Example 4.1

/**
 *  This code is edited from the book:
 *
 *    Winder, R and Roberts, G (1998) 
 *    Developing Java Software
 *    John Wiley & Sons.
 *
 *  It is copyright (c) 1997 Russel Winder 
 *  and Graham Roberts.
 */
class Calculate extends Thread{

  private int id ;

  public Calculate(int i){
	id = i ;
  }

  // Do some sort of calculation
  public void run(){
	System.out.println("Calculation "
					   + id + "started") ;
	int x = 2 ;
	for (int n = 0 ; n < 1000000 ; n++){
	  x = x * 2 / 2 ;
	}
	System.out.println("Calculation "
					   + id + "done") ;
  }
}

class ThreadTest4{
  public static void main(String[] args){
	// Create an array of threads and start each
	// one.
	Thread t[] = new Thread[10] ;
	for (int i = 0 ; i < 10 ; i++){
	  t[i] = new Calculate(i) ;
	  t[i].start() ;
	}
	// Join to each thread in order, so that the
	// main program thread does not terminate
	// until all the threads have finished.
	for (int i = 0 ; i < 10 ; i++){
	  try{
		t[i].join() ;
		System.out.println("Calculate " + i
						   + " joined") ;
	  }
	  catch (InterruptedException e){
	  }
	}
  }
}