import java.util.ArrayList;
import java.util.List;

/**
 * {@link <a href=
 * "https://[Log in to view URL]"
 * target= "_blank">Thread, produttore-consumatore</a>}
 * 
 * @author itammb ( Italia Massimiliano Buscati )
 * @version JDK 1.15
 *
 */
class Main {
	public final static class ThreadProducer extends Thread {
		// struttura condivisa: coda
		private final List<Integer> fifo;
		private int capacity = 2;

		private Thread consumer;

		public synchronized boolean isEmpty() {
			return fifo.isEmpty();
		}

		public synchronized Thread getConsumer() {
			return consumer;
		}

		public synchronized void setConsumer(Thread consumer) {
			this.consumer = consumer;
		}

		public synchronized void putResource(int resource) throws InterruptedException {
			// test: struttura condivisa piena
			while (fifo.size() == capacity)
				wait();

			fifo.add(resource);

			System.out.println("risorsa prodotta --> " + resource);
			Thread.sleep(1000);

			notify();
		}

		public synchronized int getResource() throws InterruptedException {
			notify();

			// test: struttura condivisa è vuota
			while (fifo.isEmpty())
				wait();

			Thread.sleep(1000);

			return fifo.remove(0);
		}

		public ThreadProducer() {
			fifo = new ArrayList<Integer>();
		}
	}

	public final static class ThreadConsumer extends Thread {
		private ThreadProducer producer;

		public synchronized ThreadProducer getProducer() {
			return producer;
		}

		public synchronized void setProducer(ThreadProducer producer) {
			this.producer = producer;
		}
	}

	private static class UniTest {

		public void simulate(ThreadProducer producer, ThreadConsumer consumer) throws InterruptedException {

			configureThread(producer, consumer);
			generateResource(producer);
			estractorResource(consumer);
		}

		private void configureThread(ThreadProducer producer, ThreadConsumer consumer) {
			consumer.setProducer(producer);
			producer.setConsumer(consumer);
			producer.start();
			consumer.start();
		}

		private void generateResource(ThreadProducer producer) {
			Thread inputCycle = new Thread(new Runnable() {
				int value = 0;

				@Override
				public void run() {
					try {
						while (true)
							producer.putResource(value++);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
			});

			inputCycle.start();
		}

		private void estractorResource(ThreadConsumer consumer) throws InterruptedException {

			Thread outputCycle = new Thread(new Runnable() {
				@Override
				public void run() {
					try {
						while (true)
							System.out.println("risorsa consumata --> " + consumer.getProducer().getResource());
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
			});

			outputCycle.start();
			outputCycle.join();
		}
	}

	public static void main(String args[]) {
		// Unit test - simulazione
		try {
			new UniTest().simulate(new ThreadProducer(), new ThreadConsumer());
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}