/* This program illustrates the difference between a thread object and
   a synchronization object.
*/

// a synchronization class:
class A
{
    int x = 1;

    public synchronized void f(int callerid)
    {
        System.out.println(callerid+" is calling A.f");
        System.out.println("this.x is "+this.x);
	// get a pointer to the thread that's running this code:
	T ct = (T)Thread.currentThread();
	// note the type down-casting from Thread to T
        System.out.println("Thread.currentThread().x is "+ ct.x);
    }
}  // A


// a thread class:
class T extends Thread
{
    int x = 2;
    A a0;
    int id;
    public T(int id, A x) {a0=x; this.id=id;}

    public void run()
    {
     try
     {
	for (int i=0;i<10;i++)
	{
	    a0.f(id);
	    Thread.sleep(1000); // 1 second delay
	}
     }
     catch(InterruptedException ie) {System.out.println(ie);}
    } // run
} // T


public class whatsthis
{
    public static void main(String[] args) throws InterruptedException
    {
	A s = new A();
	T t1, t2;
	t1 = new T(1,s);
	t2 = new T(2,s);
	t1.start();
	t2.start();
	t1.join();
	t2.join();
    } // main
} 

/*
   The A object s is just an inert entity.
*/