Java InetAddress createDatagramSocket(InetAddress addr, int port)

Description

Creates a DatagramSocket bound to addr.

License

LGPL

Parameter

Parameter	Description
addr	The InetAddress to which the socket should be bound. If null, the socket will not be bound.
port	The port which the socket should use. If 0, a random port will be used. If > 0, but port is already in use, it will be incremented until an unused port is found, or until MAX_PORT is reached.

Declaration

public static DatagramSocket createDatagramSocket(InetAddress addr, int port) throws Exception 

Method Source Code

//package com.java2s;

import java.net.BindException;
import java.net.DatagramSocket;

import java.net.InetAddress;

import java.net.SocketException;

public class Main {
    public static final int MAX_PORT = 65535;

    /**/*from w  w w.  j av  a 2 s . c om*/
     * Creates a DatagramSocket bound to addr. If addr is null, socket won't be bound. If address is already in use,
     * start_port will be incremented until a socket can be created.
     * @param addr The InetAddress to which the socket should be bound. If null, the socket will not be bound.
     * @param port The port which the socket should use. If 0, a random port will be used. If > 0, but port is already
     *             in use, it will be incremented until an unused port is found, or until MAX_PORT is reached.
     */
    public static DatagramSocket createDatagramSocket(InetAddress addr, int port) throws Exception {
        DatagramSocket sock = null;

        if (addr == null) {
            if (port == 0) {
                return new DatagramSocket();
            } else {
                while (port < MAX_PORT) {
                    try {
                        return new DatagramSocket(port);
                    } catch (SocketException bind_ex) { // port already used
                        if (treatAsBindException(bind_ex)) { // GemStone Addition
                            port++;
                        } else {
                            throw bind_ex;
                        }
                    } catch (Exception ex) {
                        throw ex;
                    }
                }
            }
        } else {
            if (port == 0)
                port = 1024;
            while (port < MAX_PORT) {
                try {
                    return new DatagramSocket(port, addr);
                } catch (SocketException bind_ex) { // port already used
                    if (treatAsBindException(bind_ex)) { // GemStone Addition
                        port++;
                    } else {
                        throw bind_ex;
                    }
                } catch (Exception ex) {
                    throw ex;
                }
            }
        }
        return sock; // will never be reached, but the stupid compiler didn't figure it out...
    }

    public static boolean treatAsBindException(SocketException se) {
        if (se instanceof BindException) {
            return true;
        }
        final String msg = se.getMessage();
        return (msg != null && msg.contains("Invalid argument: listen failed"));
    }
}

Related

1. contains(InetAddress network, InetAddress netmask, InetAddress ip)
2. convertInetAddressToLong(InetAddress addr)
3. convertInetAddressToLong(InetAddress address)
4. convertLongToInetAddress(long address)
5. createAbsoluteURL(InetAddress address, int localStreamPort, URI relativeOrNot)
6. createInetSocketAddress(final InetAddress address)
7. createResolved(InetAddress address, int port)
8. createSocket(InetAddress address, int port, boolean fixedPort)
9. doMatch(InetAddress inetAddress, String toMatchParam)