package examples;

import java.awt.Color;
import java.awt.Font;
import java.awt.GridLayout;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.locks.ReentrantLock;

import javax.swing.JFrame;
import javax.swing.JProgressBar;
import javax.swing.border.LineBorder;

import static java.awt.Color.*;


public class DiningPhilosopher4 extends JProgressBar implements Runnable {
	private static final long serialVersionUID = 1L;
	
	static enum State {WAIT, EAT, DONE, THINK};
	static Color[] stateColors = {RED, GREEN, YELLOW, BLACK};
	static LineBorder[] borders = new LineBorder[4];
	static final int SATIATED = 100;
	static Random random = new Random();
	static int numPhilosophers = 0;
	static List<ReentrantLock> locks = new ArrayList<ReentrantLock>();
	
	static {for (int i = 0; i < stateColors.length; i++) borders[i] = new LineBorder(stateColors[i], 5); }
	
	int id;

	public DiningPhilosopher4() {
		super(0, SATIATED);
		setFont(new Font("helvetica", Font.BOLD, 18));
		setStringPainted(true);
		id = getNextID();
		setState(State.THINK);
	}
	
	static int getNextID() {
		locks.add(new ReentrantLock());
		return numPhilosophers++;
	}
	
	public void run() {
		for (int i = 0; i < SATIATED; i++)  {
			for (State s : State.values())
				setState(s);
		}
	}
	
	void setState(State s) {
		setBorder(borders[s.ordinal()]);
		setString(s.toString());
		
		switch (s) {
		case WAIT:
			if (id == numPhilosophers-1) {
				locks.get(0).lock();
				rest(50);
				locks.get(id).lock();
			} else {
				locks.get(id).lock();
				rest(50);
				locks.get((id+1) % numPhilosophers).lock();
			}
			break;
		case EAT:
			setValue(getValue()+1);
			rest(random.nextInt(500));
			break;
		case DONE:
			locks.get(id).unlock();
			locks.get((id+1) % numPhilosophers).unlock();
			break;
		case THINK:
			rest(random.nextInt(500));			
			break;
		}
	}
	
	static void rest(int milliseconds) {
		try {
			Thread.sleep(milliseconds);
		} catch (InterruptedException ie) {
			// wake up
		}
	}
	
	public static void main(String[] args) {
		JFrame f = new JFrame();
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		f.setLayout(new GridLayout(0,1));
		for (int i = 0; i < 5; i++)
			f.add(new DiningPhilosopher4());
		f.setSize(300,200);
		f.setVisible(true);
		rest(1000);
		for (java.awt.Component c : f.getContentPane().getComponents()) {
			(new Thread((DiningPhilosopher4) c)).start();
		}
	}
	
}