Package org.apache.commons.jcs3.utils.net

Class HostNameUtil

java.lang.Object

org.apache.commons.jcs3.utils.net.HostNameUtil

public class HostNameUtil
extends Object

Simple utility for getting the local host name.

Constructor Summary

Constructors

Constructor	Description
HostNameUtil()

Method Summary

Modifier and Type	Method	Description
static String	getLocalHostAddress()	Gets the address for the local machine.
static InetAddress	getLocalHostLANAddress()	Returns an InetAddress object encapsulating what is most likely the machine's LAN IP address.
static List<InetAddress>	getLocalHostLANAddresses()	Returns all InetAddress objects encapsulating what are most likely the machine's LAN IP addresses.
static NetworkInterface	getMulticastNetworkInterface()	On systems with multiple network interfaces and mixed IPv6/IPv4 get a valid network interface for binding to multicast

Methods inherited from class java.lang.Object

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

Constructor Details

HostNameUtil

public HostNameUtil()

Method Details

getLocalHostAddress

public static String getLocalHostAddress()
                                  throws UnknownHostException

Gets the address for the local machine.

Returns:

InetAddress.getLocalHost().getHostAddress()

Throws:

UnknownHostException

getLocalHostLANAddress

public static InetAddress getLocalHostLANAddress()
                                          throws UnknownHostException

Returns an InetAddress object encapsulating what is most likely the machine's LAN IP address.

This method is intended for use as a replacement of JDK method InetAddress.getLocalHost, because that method is ambiguous on Linux systems. Linux systems enumerate the loopback network interface the same way as regular LAN network interfaces, but the JDK InetAddress.getLocalHost method does not specify the algorithm used to select the address returned under such circumstances, and will often return the loopback address, which is not valid for network communication. Details here.

This method will scan all IP addresses on all network interfaces on the host machine to determine the IP address most likely to be the machine's LAN address. If the machine has multiple IP addresses, this method will prefer a site-local IP address (e.g. 192.168.x.x or 10.10.x.x, usually IPv4) if the machine has one (and will return the first site-local address if the machine has more than one), but if the machine does not hold a site-local address, this method will return simply the first non-loopback address found (IPv4 or IPv6).

If this method cannot find a non-loopback address using this selection algorithm, it will fall back to calling and returning the result of JDK method InetAddress.getLocalHost.

JIR ISSUE JCS-40

Returns:

InetAddress

Throws:

UnknownHostException - If the LAN address of the machine cannot be found.

Since:

3.1

getLocalHostLANAddresses

public static List<InetAddress> getLocalHostLANAddresses()
                                                  throws UnknownHostException

Returns all InetAddress objects encapsulating what are most likely the machine's LAN IP addresses.

This method will scan all IP addresses on all network interfaces on the host machine to determine the IP addresses most likely to be the machine's LAN addresses.

Returns:

List

Throws:

UnknownHostException - If the LAN address of the machine cannot be found.

getMulticastNetworkInterface

public static NetworkInterface getMulticastNetworkInterface()
                                                     throws SocketException

On systems with multiple network interfaces and mixed IPv6/IPv4 get a valid network interface for binding to multicast

Returns:

a network interface suitable for multicast

Throws:

SocketException - if a problem occurs while reading the network interfaces