org.ow2.clif.util

Class Network

java.lang.Object

org.ow2.clif.util.Network

public abstract class Network
extends java.lang.Object

This utility class provides a method to get all IPv4 addresses of local network interfaces, either randomly or in a round-robin way. If at least an IPv4 address is configured, then loopback/localhost addresses are ignored. Otherwise, if no network interface holds any configured IPv4 address, a default localhost address will be selected. IPv6 addresses are ignored anyway. The main() method provides a helper that smartly chooses and prints a local address from which a given remote address can be reached.

Author:

Bruno Dillenseger

Field Summary

Fields

Modifier and Type	Field and Description
protected static java.util.List<java.net.InterfaceAddress>	allAddresses

Constructor Summary

Constructors

Constructor and Description
Network()

Method Summary

Modifier and Type	Method and Description
static boolean	belongsToSubnet(java.net.Inet4Address address, java.lang.String subnet) Checks if a given IPv4 address belongs to a given subnet
static java.net.InetAddress	getInetAddress(java.lang.String subnet)
static java.net.InetAddress[]	getInetAddresses() Get all locally available IPv4 addresses but the loopback address.
static boolean	isLocalAddress(java.net.InetAddress address) Checks that the given IP address is bound to a local network interface
static boolean	isLocalAddress(java.lang.String address) Checks that the given IP address is bound to a local network interface
static void	main(java.lang.String[] args) Prints to standard output the local IP address from which the provided host IP address or name is reachable.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

allAddresses

protected static java.util.List<java.net.InterfaceAddress> allAddresses

Constructor Detail

Network

public Network()

Method Detail

getInetAddress

public static java.net.InetAddress getInetAddress(java.lang.String subnet)

Parameters:

subnet - if not null, this string must specify an IPv4 subnetwork address in the form b1.b2.b3.b4/maskbits (e.g. 192.168.1.0/24)

Returns:

an arbitrary local IPv4 address belonging to the specified subnet if not null. Successive calls always return the same address.

getInetAddresses

public static java.net.InetAddress[] getInetAddresses()

Get all locally available IPv4 addresses but the loopback address. Nevertheless, when the loopback address is the only one configured, it is returned.

Returns:

either all locally available IPv4 addresses different from the loopback address, or just the loopback address if it is the only one configured.

belongsToSubnet

public static boolean belongsToSubnet(java.net.Inet4Address address,
                                      java.lang.String subnet)

Checks if a given IPv4 address belongs to a given subnet

Parameters:

address - the IPv4 address

subnet - the subnet address, specified as b1.b2.b3.b4/maskbits (e.g. 192.168.1.0/24)

Returns:

true if the address belongs to the subnet, false otherwise

isLocalAddress

public static boolean isLocalAddress(java.lang.String address)

Checks that the given IP address is bound to a local network interface

Parameters:

address - the classical String representation (xxx.xxx.xxx.xxx) of the IP address to check

Returns:

true if the address is bound to a local network interface, false otherwise

isLocalAddress

public static boolean isLocalAddress(java.net.InetAddress address)

Checks that the given IP address is bound to a local network interface

Parameters:

address - the IP address to check

Returns:

true if the address is bound to a local network interface, false otherwise

main

public static void main(java.lang.String[] args)

Prints to standard output the local IP address from which the provided host IP address or name is reachable. Keeps mute if no local address routes to the target host. Reports possible error messages to the standard error output. Exits with status code 0 if a correct local address was found, 1 if the target host is unreachable from any local address, or a greater value if an error occurred. The output is printed as: "network.address=ddd.ddd.ddd.ddd/nn"

Parameters:

args - 2 arguments expected: args[0] the target host IP address or name, args[1] the timeout in seconds for reachability assessment of each local address.