ConnectionManager.java

import java.lang.reflect.Array;
import java.util.*;
import java.net.*;
import java.io.*;


public class ConnectionManager {
  private InetAddress hostAddr;
  private static final int MIN_PORT = 10000;
  private static final int MAX_PORT = 11000;
  private int connectionPort;

  ConnectionManager() throws SocketException {
    hostAddr = getNextNonLoopbackAddr();
  }

  /**
   * Credit: This code snippet was taken from :
   * http://www.java2s.com/Code/Java/Network-Protocol/FindsalocalnonloopbackIPv4address.htm
   */
  private InetAddress getNextNonLoopbackAddr() throws SocketException {
    Enumeration<NetworkInterface> ifaceList = NetworkInterface.getNetworkInterfaces();
    while ( ifaceList.hasMoreElements() ) {
      NetworkInterface iface = ifaceList.nextElement();
      Enumeration<InetAddress> addresses = iface.getInetAddresses();

      while ( addresses.hasMoreElements() ) {
        InetAddress addr = addresses.nextElement();
        if ( addr instanceof Inet4Address && !addr.isLoopbackAddress() ) {
          return addr;
        }
      }
    }
    return null;
  }

  public ServerSocket getAvailableConnection() throws IOException {
    // Generate random port
    int port = MIN_PORT;
    ServerSocket conn = new ServerSocket();
    while ( port <= MAX_PORT ) {
      try {
        conn.bind(new InetSocketAddress(hostAddr, port));;
        break;
      } catch (IOException e) {
        port++;
      }
    }

    connectionPort = port;
    conn.setReuseAddress(false);
    return conn;
  }

  public int getConnectionPort() {
    return connectionPort;
  }

  public String getHostName() {
    return hostAddr.getHostAddress();
  }
}