package examples;

import java.util.concurrent.locks.*;

public class ex49c
{
	public static void main(String[] args)
	{
		DataItem item = new DataItem(0);
		Producer producer = new Producer(item);
		Consumer consumer = new Consumer(item);

		producer.start();
		consumer.start();
	}

	public static class DataItem
	{
		private int	data;
		private boolean available = false;
		
		private Lock lock;
		private Condition cond;

		public DataItem(int num)
		{
			data = num;
			lock = new ReentrantLock();
			cond = lock.newCondition();
		}

		public void put(int item)
		{
			lock.lock();
			try
			{
				while(available)
					try{cond.await();}catch(InterruptedException ie){}
				data = item;
				available = true;
				
				cond.signalAll();
			}
			finally
			{
				lock.unlock();
			}
		}

		public int get()
		{
			int temp;
			lock.lock();
			try
			{
			while(!available)
				try{cond.await();}catch(InterruptedException ie){}
			
			available = false;
			temp = data;
			
			cond.signalAll();
			}
			finally
			{
				lock.unlock();
			}
			return temp;
		}
	}

	public static class Producer extends Thread
	{
		private DataItem	item;

		public Producer(DataItem dataItem)
		{
			item = dataItem;
		}

		public void run()
		{
			for (int i = 0; i < 10; i++)
			{
				item.put(i);
				System.out.println("Producer: put: " + i);

				try
					{sleep((int) (Math.random() * 100));}
				catch (InterruptedException ie){}
			}
		}
	}

	public static class Consumer extends Thread
	{
		private DataItem	item;

		public Consumer(DataItem dataItem)
		{
			item = dataItem;
		}

		public void run()
		{
			int value;
			for (int i = 0; i < 10; i++)
			{
				value = item.get();
				System.out.println("Consumer: got: " + value);

				try
				{
					sleep((int) (Math.random() * 100));
				}
				catch (InterruptedException ie)
				{
				}
			}
		}
	}
}