Example_UDP_TCP.java

/**
 * Copyright (C) 2010-2017 Gordon Fraser, Andrea Arcuri and EvoSuite
 * contributors
 *
 * This file is part of EvoSuite.
 *
 * EvoSuite is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3.0 of the License, or
 * (at your option) any later version.
 *
 * EvoSuite is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with EvoSuite. If not, see <http://www.gnu.org/licenses/>.
 */
package com.examples.with.different.packagename.papers.vnet;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;


public class Example_UDP_TCP {

	public String getMessage(int port) throws IOException{

		//defines message to send in UDP broadcast
		InetAddress addr = InetAddress.getByName("192.168.0.1");
		String handShake = "HAND_SHAKE";
		String outMsg = addr+":"+port+":"+handShake;
		byte[] data = outMsg.getBytes();

		//send the message
		DatagramPacket packet = new DatagramPacket(data,data.length,
				InetAddress.getByName("255.255.255.255"),12345);
		DatagramSocket udpSocket = new DatagramSocket();
		udpSocket.send(packet);

		//open listening TCP server based on sent out message
		ServerSocket tcpServer = new ServerSocket(port,1,addr);
		Socket tcpSocket = tcpServer.accept();

		//read string from incoming TCP connection
		Scanner in = new Scanner(tcpSocket.getInputStream());
		String msg = in.nextLine();

		//close all resources
		in.close();
		tcpSocket.close();
		tcpServer.close();

		//check if first line contains the handshake token
		if( msg.startsWith(handShake)){
			return msg;
		} else{
			throw new IOException("Invalid header in: "+msg);
		}
	}
}