JWS Task 4: Multithreading and Conway’s Life

Write Endpoint Publisher that uses threads executer to support multithreading and simple graphical end-user client.
Use basic implementation of Conway’s Game of Life as web method.

 

 

 

 

 

Example Solution

Service Implementation Bean

package com.fuzilaga.jws.conwayslife;

import javax.jws.WebService;

@WebService(endpointInterface = "com.fuzilaga.jws.conwayslife.ConwaysLifeService")
public class ConwaysLifeServiceImpl implements ConwaysLifeService
{

	private int[][] map;

	@Override
	public int[][] nextGeneration()
	{
		if (null == map)
		{
			return null;
		}

		int[][] newMap = new int[map.length][map.length];
		for (int i = 0; i < map.length; i++)
		{
			for (int j = 0; j < map.length; j++)
			{
				int countNeighbours = countNeighbours(i, j);
				if (countNeighbours < 2 || countNeighbours > 3)
				{
					newMap[i][j] = 0;
				}
				else if (countNeighbours == 3)
				{
					newMap[i][j] = 1;
				}
				else
				{
					newMap[i][j] = map[i][j];
				}
			}
		}

		map = newMap;
		return map;
	}

	@Override
	public void createGeneration(int[][] map)
	{
		this.map = map;
	}

	private int countNeighbours(int i, int j)
	{
		int count = 0;
		int[][] neighbours = new int[][] { { i - 1, j - 1 }, { i, j - 1 }, { i + 1, j - 1 }, { i - 1, j }, { i + 1, j }, { i - 1, j + 1 }, { i, j + 1 }, { i + 1, j + 1 } };
		for (int k = 0; k < neighbours.length; k++)
		{
			int x = neighbours[k][0];
			int y = neighbours[k][1];
			if (x >= 0 && y >= 0 && x < map.length && y < map.length)
			{
				count += map[x][y];
			}
		}
		return count;
	}

}

Service Publisher

package com.fuzilaga.jws.conwayslife;

import java.util.concurrent.Executors;
import javax.xml.ws.Endpoint;

public class ConwaysLifeServicePublisher
{
	public static void main(String args[])
	{
		Endpoint endpoint = Endpoint.create(new ConwaysLifeServiceImpl());
		endpoint.setExecutor(Executors.newFixedThreadPool(4));
		endpoint.publish("http://localhost:8880/conway");
	}
}

Service Client

package com.fuzilaga.jws.conwayslife;

import java.awt.Color;
import java.awt.Graphics;
import java.net.URL;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.xml.namespace.QName;
import javax.xml.ws.Service;

public class ConwaysLifeClient extends JPanel implements Runnable
{
	private int width = 310, height = 335, areaWidth = 30, areaHeight = 30;
	private int[][] map = new int[areaWidth][areaHeight];
	private ConwaysLifeService conway;

	public void paintComponent(Graphics g)
	{
		g.clearRect(0, 0, width, height);
		g.setColor(Color.BLUE);
		for (int i = 0; i < areaWidth; i++)
		{
			for (int j = 0; j < areaHeight; j++)
			{
				if (map[i][j] == 1)
				{
					g.fillOval(i * 10, j * 10, 7, 7);
				}
				else
				{
					g.drawOval(i * 10, j * 10, 7, 7);
				}
			}
		}
	}

	public void run()
	{
		try
		{
			while (null != conway)
			{
				Thread.sleep(500);
				map = conway.nextGeneration();
				repaint();
			}
		} catch (Exception e)
		{
			e.printStackTrace();
		}
	}

	public static void main(String args[]) throws Exception
	{
		ConwaysLifeClient client = new ConwaysLifeClient();
		client.map[15][14] = client.map[15][15] = client.map[15][16] = client.map[14][15] = client.map[16][16] = 1;
		JFrame frame = new JFrame("Conway's Life");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.add(client);
		frame.setSize(client.width, client.height);
		frame.setVisible(true);

		URL url = new URL("http://localhost:8880/conway");
		QName qname = new QName("http://conwayslife.jws.fuzilaga.com/", "ConwaysLifeServiceImplService");
		Service service = Service.create(url, qname);
		client.conway = service.getPort(ConwaysLifeService.class);
		client.conway.createGeneration(client.map); // set initial map

		Thread t = new Thread(client);
		t.start();
	}
}

Screenshot of four simultaneously running clients:

NOTE: Full source and instructions on how to run locally can be found here.