/**
 * This server socket program has been created to test the programe with -client and -server JVM parameters.
 */
package sockets;

import java.io.IOException;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingQueue;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author prabhu kvn
 *
 */
public class ServerSocketDemoWithBlockingQueue {

	Logger logger = LoggerFactory.getLogger(this.getClass().getName());

	/**
	 * A blocking queue to handle connections. this can hold up to one lakh sockets
	 */
	/**
	 * Default values
	 */
	private int queueLength = 10000;
	int serverThreadCount = 1;
	BlockingQueue<Socket> queue = new LinkedBlockingQueue<>(queueLength);

	/**
	 * Default Constructor
	 */
	public ServerSocketDemoWithBlockingQueue() {

	}

	/**
	 * Default Constructor
	 */
	public ServerSocketDemoWithBlockingQueue(int serverThreadCount, int queueLength) {

		this.serverThreadCount = serverThreadCount;
		this.queueLength = queueLength;
		this.queue = new LinkedBlockingQueue<>(queueLength);

	}

	/**
	 * Entry point for server start up
	 * 
	 * @param args
	 */
	public static void main(String[] args) {

		ServerSocketDemoWithBlockingQueue demo = new ServerSocketDemoWithBlockingQueue();
		demo.startServer();
	}

	/**
	 * Starting the server to handle asynch connections
	 */
	private void startServer() {

		logger.info("Starting the server with {} threads and queue size {}", serverThreadCount, queueLength);
		ExecutorService service = Executors.newFixedThreadPool(serverThreadCount);
		for (int i = 0; i < serverThreadCount; i++) {
			service.submit(new ServerProcessing(queue));
		}
		ServerSocket serverSocket = null;
		try {

			// create the server socket
			serverSocket = new ServerSocket(8181, 100000);

			while (true) {
				Socket socket = serverSocket.accept();
				try {
					queue.put(socket);
				} catch (InterruptedException e) {
					logger.error("Problem in accepting new connections : {}", e);
					e.printStackTrace();
				}

			}

		} catch (IOException e) {
			logger.error("Problem in creating server socket {}", e);
			e.printStackTrace();
		} finally {
			if (null != serverSocket) {
				try {
					serverSocket.close();
					logger.info("Server Socket closed Successfully.");
				} catch (IOException e) {
					logger.error("Problem in closing server socket.");
					e.printStackTrace();
				}
			}
		}

	}

}

/**
 * Processing class
 * 
 * @author prabhukvn
 *
 */
class ServerProcessing extends Thread {
	BlockingQueue<Socket> queue;
	volatile int counter = 0;

	public ServerProcessing(BlockingQueue<Socket> queue) {
		this.queue = queue;
	}

	@Override
	public void run() {
		while (true) {
			try {

				process(queue.take());
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (SocketException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}

	/**
	 * Execute the actual work.F
	 * @param socket
	 * @return
	 * @throws IOException
	 * @throws SocketException
	 * @throws InterruptedException
	 */
	private int process(Socket socket) throws IOException, SocketException, InterruptedException {
		System.out.println("Server Socket:" + socket);
		OutputStream out = socket.getOutputStream();
		out.write(("Request received" + counter).getBytes());
		counter++;
		socket.setKeepAlive(true);
		// Thread.sleep(1000);
		// allow client to close the connection
		socket.close();
		return counter;
	}
}