import java.util.Random;

/**
 * Solves the dining philosophers problem
 * 
 * @author Scot Drysdale
 */
public class PhilosopherMonitor extends Thread {
	private int myNum; // Number of this philosopher
	private ForksMonitor forks;
	private Random generator;
	private static final int EAT_TIME = 1000;
	private static final int THINK_TIME = 1000;
	private static final int NUM_MEALS = 10;
	private static final int NUM_PHILOSOPHERS = 6;

	public PhilosopherMonitor(int philNum, ForksMonitor theForks) {
		myNum = philNum;
		forks = theForks;
		generator = new Random();
	}

	/**
	 * Eat using a monitor to control the forks
	 * 
	 * @param meal
	 *          the number of the meal eaten
	 */
	public void eat(int meal) throws InterruptedException {

		System.out.println("Philosopher " + myNum + " trys to pick up forks");
		forks.pickUpForks(myNum);
		System.out.println("Philosopher " + myNum
				+ " picks up forks and eats meal " + meal);

		sleep(EAT_TIME + generator.nextInt(EAT_TIME));

		System.out.println("Philosopher " + myNum + " puts down forks and thinks");
		forks.putDownForks(myNum);

		sleep(THINK_TIME + generator.nextInt(THINK_TIME));
	}

	/**
	 * The code to eat NUM_MEALS meals is in the run method of the thread.
	 */
	public void run() {
		try {
			for (int meal = 1; meal <= NUM_MEALS; meal++)
				eat(meal);
		}
		catch (InterruptedException e) {
		}
	}

	/**
	 * Create NUM_PHILOSOPHERS philosopher threads and start them eating
	 */
	public static void main(String[] args) {
		ForksMonitor forks = new ForksMonitor(NUM_PHILOSOPHERS);

		for (int num = 0; num < NUM_PHILOSOPHERS; num++) {
			PhilosopherMonitor phil = new PhilosopherMonitor(num, forks);
			phil.start();
		}
	}
}