java.net
Class InetAddress

java.lang.Object
  java.net.InetAddress

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

Inet4Address, Inet6Address

public class InetAddress
extends Object
implements Serializable

This class models an Internet address. It does not have a public constructor. Instead, new instances of this objects are created using the static methods getLocalHost(), getByName(), and getAllByName().

This class fulfills the function of the C style functions gethostname(), gethostbyname(), and gethostbyaddr(). It resolves Internet DNS names into their corresponding numeric addresses and vice versa.

See Also:

Serialized Form

Specnote:

This class is not final since JK 1.4

Method Summary

boolean	equals(Object obj) Tests this address for equality against another InetAddress.
byte[]	getAddress() Returns the IP address of this object as a byte array.
static InetAddress[]	getAllByName(String hostname) Returns an array of InetAddress objects representing all the host/ip addresses of a given host, given the host's name.
static InetAddress	getByAddress(byte[] addr) Returns an InetAddress object given the raw IP address.
static InetAddress	getByAddress(String host, byte[] addr) Creates an InetAddress based on the provided host name and IP address.
static InetAddress	getByName(String hostname) Returns an InetAddress object representing the IP address of the given hostname.
String	getCanonicalHostName() Returns the canonical hostname represented by this InetAddress
String	getHostAddress() Returns the IP address of this object as a String.
String	getHostName() Returns the hostname for this address.
static InetAddress	getLocalHost() Returns an InetAddress object representing the address of the current host.
int	hashCode() Returns a hash value for this address.
boolean	isAnyLocalAddress() Utility routine to check if the InetAddress in a wildcard address
boolean	isLinkLocalAddress() Utility routine to check if InetAddress is a link local address
boolean	isLoopbackAddress() Utility routine to check if the InetAddress is a loopback address
boolean	isMCGlobal() Utility routine to check if InetAddress is a global multicast address
boolean	isMCLinkLocal() Utility routine to check if InetAddress is a link local multicast address.
boolean	isMCNodeLocal() Utility routine to check if InetAddress is a node local multicast address.
boolean	isMCOrgLocal() Utility routine to check if InetAddress is a organization local multicast address.
boolean	isMCSiteLocal() Utility routine to check if InetAddress is a site local multicast address.
boolean	isMulticastAddress() Returns true if this address is a multicast address, false otherwise.
boolean	isSiteLocalAddress() Utility routine to check if InetAddress is a site local address
String	toString() Converts this address to a String.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

isMulticastAddress

public boolean isMulticastAddress()

Returns true if this address is a multicast address, false otherwise. An address is multicast if the high four bits are "1110". These are also known as "Class D" addresses.

Returns:

true if mulitcast, false if not

Since:

1.1

isAnyLocalAddress

public boolean isAnyLocalAddress()

Utility routine to check if the InetAddress in a wildcard address

Since:

1.4

isLoopbackAddress

public boolean isLoopbackAddress()

Utility routine to check if the InetAddress is a loopback address

Since:

1.4

isLinkLocalAddress

public boolean isLinkLocalAddress()

Utility routine to check if InetAddress is a link local address

Since:

1.4

isSiteLocalAddress

public boolean isSiteLocalAddress()

Utility routine to check if InetAddress is a site local address

Since:

1.4

isMCGlobal

public boolean isMCGlobal()

Utility routine to check if InetAddress is a global multicast address

Since:

1.4

isMCNodeLocal

public boolean isMCNodeLocal()

Utility routine to check if InetAddress is a node local multicast address.

Since:

1.4

isMCLinkLocal

public boolean isMCLinkLocal()

Utility routine to check if InetAddress is a link local multicast address.

Since:

1.4

isMCSiteLocal

public boolean isMCSiteLocal()

Utility routine to check if InetAddress is a site local multicast address.

Since:

1.4

isMCOrgLocal

public boolean isMCOrgLocal()

Utility routine to check if InetAddress is a organization local multicast address.

Since:

1.4

getHostName

public String getHostName()

Returns the hostname for this address. This will return the IP address as a String if there is no hostname available for this address

Returns:

The hostname for this address

getCanonicalHostName

public String getCanonicalHostName()

Returns the canonical hostname represented by this InetAddress

Since:

1.4

getAddress

public byte[] getAddress()

Returns the IP address of this object as a byte array.

Returns:

IP address

getHostAddress

public String getHostAddress()

Returns the IP address of this object as a String. The address is in the dotted octet notation, for example, "127.0.0.1".

Returns:

The IP address of this object in String form

Since:

1.0.2

hashCode

public int hashCode()

Returns a hash value for this address. Useful for creating hash tables. Overrides Object.hashCode()

Overrides:

hashCode in class Object

Returns:

A hash value for this address.

equals

public boolean equals(Object obj)

Tests this address for equality against another InetAddress. The two addresses are considered equal if they contain the exact same octets. This implementation overrides Object.equals()

Overrides:

equals in class Object

Parameters:

obj - The address to test for equality

Returns:

true if the passed in object's address is equal to this one's, false otherwise

toString

public String toString()

Converts this address to a String. This string contains the IP in dotted decimal form. For example: "127.0.0.1" This method is equivalent to getHostAddress() and overrides Object.toString()

Overrides:

toString in class Object

Returns:

This address in String form

getByAddress

public static InetAddress getByAddress(byte[] addr)
                                throws UnknownHostException

Returns an InetAddress object given the raw IP address. The argument is in network byte order: the highest order byte of the address is in getAddress()[0].

Parameters:

addr - The IP address to create the InetAddress object from

Throws:

UnknownHostException - If IP address has illegal length

Since:

1.4

getByAddress

public static InetAddress getByAddress(String host,
                                       byte[] addr)
                                throws UnknownHostException

Creates an InetAddress based on the provided host name and IP address. No name service is checked for the validity of the address.

Parameters:

host - The hostname of the InetAddress object to create

addr - The IP address to create the InetAddress object from

Throws:

UnknownHostException - If IP address is of illegal length

Since:

1.4

getByName

public static InetAddress getByName(String hostname)
                             throws UnknownHostException

Returns an InetAddress object representing the IP address of the given hostname. This name can be either a hostname such as "www.urbanophile.com" or an IP address in dotted decimal format such as "127.0.0.1". If the hostname is null or "", the hostname of the local machine is supplied by default. This method is equivalent to returning the first element in the InetAddress array returned from GetAllByName.

Parameters:

hostname - The name of the desired host, or null for the local loopback address.

Returns:

The address of the host as an InetAddress object.

Throws:

UnknownHostException - If no IP address for the host could be found

SecurityException - If a security manager exists and its checkConnect method doesn't allow the operation

getAllByName

public static InetAddress[] getAllByName(String hostname)
                                  throws UnknownHostException

Returns an array of InetAddress objects representing all the host/ip addresses of a given host, given the host's name. This name can be either a hostname such as "www.urbanophile.com" or an IP address in dotted decimal format such as "127.0.0.1". If the value is null, the hostname of the local machine is supplied by default.

Parameters:

hostname - The name of the desired host, or null for the local loopback address.

Returns:

All addresses of the host as an array of InetAddress objects.

Throws:

UnknownHostException - If no IP address for the host could be found

SecurityException - If a security manager exists and its checkConnect method doesn't allow the operation

getLocalHost

public static InetAddress getLocalHost()
                                throws UnknownHostException

Returns an InetAddress object representing the address of the current host.

Returns:

The local host's address

Throws:

UnknownHostException - If no IP address for the host could be found