process Turnstile {

    private semaphore mutex_;
    
    private Counter counter_;

    public Turnstile(Counter counter, semaphore mutex) {
      
        mutex_ = mutex;
      
        counter_ = counter;
    
    } // Turnstile

	
	public void body() {
       
       for (int i=0;i<20;i++) {
			
           mutex_.down();
			
           counter_.incValue();
			
           mutex_.up();
       
       } // for      
    
    
    } // body
    
} // Turnstile