CP.java

/**
 * @author Thomas Moroney
 */

import java.net.DatagramSocket;
import java.net.DatagramPacket;
import java.net.InetSocketAddress;
import java.util.HashMap;
import java.util.Random;

public class CP extends Node {
	static final int CONTROLLER_PORT = 50000;
	static final int ISP_PORT = 50005;
	static final int CP_PORT = 50006; // <---- current node
	static final int DSERVER_PORT = 50007;
	static final int DSERVER2_PORT = 50008;
	static final String CONTROLLER_NODE = "Controller";
	static final String ISP_NODE = "ISP";
	static final String DSERVER_NODE = "DServer";
	static final String DSERVER2_NODE = "DServer2";

	InetSocketAddress dstAddress;
	HashMap<String, Integer> nextJump = new HashMap<>(); // stores the jump after asking the controller so there is no
															// need to ask again
	HashMap<Integer, String> nodeList = new HashMap<>(); // map each port to a node name
	DatagramPacket currentPacket;
	String dest; // destination of incoming packet

	CP(int port) {
		try {
			nodeList.put(ISP_PORT, ISP_NODE);
			nodeList.put(DSERVER_PORT, DSERVER_NODE);
			nodeList.put(DSERVER2_PORT, DSERVER2_NODE);
			socket = new DatagramSocket(port);
			listener.go();
		} catch (java.lang.Exception e) {
			e.printStackTrace();
		}
	}

	// handle incoming packets
	public void onReceipt(DatagramPacket packet) {
		try {

			PacketContent content = PacketContent.fromDatagramPacket(packet);

			if (content.getType() == PacketContent.TEXTPACKET) {
				System.out.println("Received packet");
				currentPacket = packet;
				TextPacket inPacket = ((TextPacket) content);
				dest = (inPacket.text).substring(0, 3); // isolate destination of packet

				if (nextJump.containsKey(dest)) {
					int destPort = nextJump.get(dest);
					System.out.println("Found next jump in forwarding table.");
					System.out.println("Forwarded packet to " + nodeList.get(destPort));
					dstAddress = new InetSocketAddress(nodeList.get(destPort), destPort);
					packet.setSocketAddress(dstAddress);
					socket.send(packet);
				} else {
					System.out.println("Next jump not stored. Requesting next jump from Controller...");
					dstAddress = new InetSocketAddress(CONTROLLER_NODE, CONTROLLER_PORT);
					packet.setSocketAddress(dstAddress);
					socket.send(packet);
				}
			} else if (content.getType() == PacketContent.NEXTNODE) {
				Random random = new Random();
				int num = random.nextInt(6);
				if (num != 0) {
					System.out.println("Received packet");
					JumpPacket inPacket = ((JumpPacket) content);
					int port = inPacket.getPort();

					DatagramPacket ackPacket;
					ackPacket = new AckPacketContent("Updated CP forwarding table").toDatagramPacket();
					dstAddress = new InetSocketAddress(CONTROLLER_NODE, CONTROLLER_PORT);
					ackPacket.setSocketAddress(dstAddress);
					socket.send(ackPacket);

					System.out.println("Controller returned next jump - updated forwarding table.");
					System.out.println("Forwarded packet to " + nodeList.get(port));

					nextJump.put(dest, port); // adds next node to hashmap for later use
					dstAddress = new InetSocketAddress(nodeList.get(port), port);
					currentPacket.setSocketAddress(dstAddress);
					socket.send(currentPacket);
				}
				else {
					System.out.println("There was disturbance in the network - next node was not received!!!");
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public synchronized void start() throws Exception {
		System.out.println("Waiting for contact");
		this.wait();
	}

	public static void main(String[] args) {
		try {
			(new CP(CP_PORT)).start();
			System.out.println("Program completed");
		} catch (java.lang.Exception e) {
			e.printStackTrace();
		}
	}
}