import java.lang.Thread;
public class RW
{
	//This is the shared object we are controlling access to
	private int theVal;
	private Semaphore S = new Semaphore(1);
	public RW()
	{		theVal = 12;	}
	private void test()
	{
		theReader r1 = new theReader("One");
		theReader r2 = new theReader("Two");
		theReader r3 = new theReader("Three");
		theWriter w1 = new theWriter("A", 111111);
		theWriter w2 = new theWriter("B", 222222);

		Thread tr1 = new Thread(r1);
		tr1.start();
		new Thread(w1).start();
		new Thread(w2).start();
		new Thread(r2).start();
		new Thread(r3).start();
	}
	// The main
	public static void main(String[] args)
	{
		RW rw = new RW();
		rw.test();
	}
	private class theReader implements Runnable
	{
		private String name;
		public theReader(String theName)
		{	name = theName;	}
		public void run()
		{
			try
			{
				S.P();
				int value = theVal;
				System.out.println("The Reader " + name + " with a value " + value);
				try
				{
					Thread.sleep(1000);
				} catch (InterruptedException e) {}
			} finally
			{
				S.V();
			}
		}

	}
	private class theWriter implements Runnable
	{	private String name;
		private int value;
		public theWriter(String theName, int theValue)
		{	name = theName;
			value = theValue;
		}
		public void run()
		{
			try
			{
				S.P();
				theVal = value;
				System.out.println("The Writer " + name + " with the value "+ value);
				try
				{
					Thread.sleep(1000);
				}
				catch (InterruptedException e)
				{}
			} finally
			{
				S.V();
			}

		}
	}
}