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

Untamed:

See Also:
Serialized Form

Field Summary
(package private)  int address
          Holds a 32-bit IPv4 address.
private static LinkedHashMap addressCache
           
private static boolean addressCacheInit
           
private  String canonicalHostName
           
(package private)  int family
          Specifies the address family type, for instance, '1' for IPv4 addresses, and '2' for IPv6 addresses.
(package private)  String hostName
           
(package private) static InetAddressImpl impl
           
(package private) static int IPv4
          Specify the address family: Internet Protocol, Version 4
(package private) static int IPv6
          Specify the address family: Internet Protocol, Version 6
private static HashMap lookupTable
           
private static sun.net.spi.nameservice.NameService nameService
           
(package private) static boolean preferIPv6Address
           
private static long serialVersionUID
          use serialVersionUID from JDK 1.0.2 for interoperability
(package private) static InetAddress[] unknown_array
           
 
Constructor Summary
(package private) InetAddress()
          Constructor for the Socket.accept() method.
 
Method Summary
(package private) static InetAddress anyLocalAddress()
           
private static void cacheAddress(String hostname, Object address, boolean success)
           
private static void cacheAddress(String hostname, Object address, long expiration)
           
private static void cacheInitIfNeeded()
           
private static Object checkLookupTable(String host)
           
 boolean equals(Object obj)
          Suppressed: Compares this object against the specified object.
 byte[] getAddress()
          Enabled: Returns the raw IP address of this InetAddress object.
private static Object getAddressFromNameService(String host)
           
static InetAddress[] getAllByName(String host)
          Enabled: Given the name of a host, returns an array of its IP addresses, based on the configured name service on the system.
private static InetAddress[] getAllByName0(String host)
           
(package private) static InetAddress[] getAllByName0(String host, boolean check)
          package private so SocketPermission can call it
static InetAddress getByAddress(byte[] addr)
          Enabled: Returns an InetAddress object given the raw IP address .
static InetAddress getByAddress(String host, byte[] addr)
          Enabled: Create an InetAddress based on the provided host name and IP address No name service is checked for the validity of the address.
static InetAddress getByName(String host)
          Enabled: Determines the IP address of a host, given the host's name.
private static Object getCachedAddress(String hostname)
           
 String getCanonicalHostName()
          Enabled: Gets the fully qualified domain name for this IP address.
 String getHostAddress()
          Enabled: Returns the IP address string in textual presentation.
private static String getHostFromNameService(InetAddress addr, boolean check)
          Returns the hostname for this address.
 String getHostName()
          Enabled: Gets the host name for this IP address.
(package private)  String getHostName(boolean check)
          Returns the hostname for this address.
static InetAddress getLocalHost()
          Enabled: Returns the local host.
 int hashCode()
          Suppressed: Returns a hashcode for this IP address.
private static void init()
          Perform class load-time initializations.
 boolean isAnyLocalAddress()
          Enabled: Utility routine to check if the InetAddress in a wildcard address.
 boolean isLinkLocalAddress()
          Enabled: Utility routine to check if the InetAddress is an link local address.
 boolean isLoopbackAddress()
          Enabled: Utility routine to check if the InetAddress is a loopback address.
 boolean isMCGlobal()
          Enabled: Utility routine to check if the multicast address has global scope.
 boolean isMCLinkLocal()
          Enabled: Utility routine to check if the multicast address has link scope.
 boolean isMCNodeLocal()
          Enabled: Utility routine to check if the multicast address has node scope.
 boolean isMCOrgLocal()
          Enabled: Utility routine to check if the multicast address has organization scope.
 boolean isMCSiteLocal()
          Enabled: Utility routine to check if the multicast address has site scope.
 boolean isMulticastAddress()
          Enabled: Utility routine to check if the InetAddress is an IP multicast address.
 boolean isSiteLocalAddress()
          Enabled: Utility routine to check if the InetAddress is a site local address.
(package private) static Object loadImpl(String implName)
           
private  Object readResolve()
          Replaces the de-serialized object with an Inet4Address object.
 String toString()
          Suppressed: Converts this IP address to a String.
private static void updateLookupTable(String host)
           
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

IPv4

static final int IPv4
Specify the address family: Internet Protocol, Version 4

Since:
1.4

IPv6

static final int IPv6
Specify the address family: Internet Protocol, Version 6

Since:
1.4

preferIPv6Address

static transient boolean preferIPv6Address

hostName

String hostName

address

int address
Holds a 32-bit IPv4 address.


family

int family
Specifies the address family type, for instance, '1' for IPv4 addresses, and '2' for IPv6 addresses.


nameService

private static sun.net.spi.nameservice.NameService nameService

canonicalHostName

private transient String canonicalHostName

serialVersionUID

private static final long serialVersionUID
use serialVersionUID from JDK 1.0.2 for interoperability


addressCache

private static LinkedHashMap addressCache

addressCacheInit

private static boolean addressCacheInit

unknown_array

static InetAddress[] unknown_array

impl

static InetAddressImpl impl

lookupTable

private static HashMap lookupTable
Constructor Detail

InetAddress

InetAddress()
Constructor for the Socket.accept() method. This creates an empty InetAddress, which is filled in by the accept() method. This InetAddress, however, is not put in the address cache, since it is not created by name.

Method Detail

readResolve

private Object readResolve()
                    throws ObjectStreamException
Replaces the de-serialized object with an Inet4Address object.

Returns:
the alternate object to the de-serialized object.
Throws:
ObjectStreamException - if a new object replacing this object could not be created

isMulticastAddress

public boolean isMulticastAddress()
Enabled: Utility routine to check if the InetAddress is an IP multicast address.

Returns:
a boolean indicating if the InetAddress is an IP multicast address
Since:
JDK1.1

isAnyLocalAddress

public boolean isAnyLocalAddress()
Enabled: Utility routine to check if the InetAddress in a wildcard address.

Returns:
a boolean indicating if the Inetaddress is a wildcard address.
Since:
1.4

isLoopbackAddress

public boolean isLoopbackAddress()
Enabled: Utility routine to check if the InetAddress is a loopback address.

Returns:
a boolean indicating if the InetAddress is a loopback address; or false otherwise.
Since:
1.4

isLinkLocalAddress

public boolean isLinkLocalAddress()
Enabled: Utility routine to check if the InetAddress is an link local address.

Returns:
a boolean indicating if the InetAddress is a link local address; or false if address is not a link local unicast address.
Since:
1.4

isSiteLocalAddress

public boolean isSiteLocalAddress()
Enabled: Utility routine to check if the InetAddress is a site local address.

Returns:
a boolean indicating if the InetAddress is a site local address; or false if address is not a site local unicast address.
Since:
1.4

isMCGlobal

public boolean isMCGlobal()
Enabled: Utility routine to check if the multicast address has global scope.

Returns:
a boolean indicating if the address has is a multicast address of global scope, false if it is not of global scope or it is not a multicast address
Since:
1.4

isMCNodeLocal

public boolean isMCNodeLocal()
Enabled: Utility routine to check if the multicast address has node scope.

Returns:
a boolean indicating if the address has is a multicast address of node-local scope, false if it is not of node-local scope or it is not a multicast address
Since:
1.4

isMCLinkLocal

public boolean isMCLinkLocal()
Enabled: Utility routine to check if the multicast address has link scope.

Returns:
a boolean indicating if the address has is a multicast address of link-local scope, false if it is not of link-local scope or it is not a multicast address
Since:
1.4

isMCSiteLocal

public boolean isMCSiteLocal()
Enabled: Utility routine to check if the multicast address has site scope.

Returns:
a boolean indicating if the address has is a multicast address of site-local scope, false if it is not of site-local scope or it is not a multicast address
Since:
1.4

isMCOrgLocal

public boolean isMCOrgLocal()
Enabled: Utility routine to check if the multicast address has organization scope.

Returns:
a boolean indicating if the address has is a multicast address of organization-local scope, false if it is not of organization-local scope or it is not a multicast address
Since:
1.4

getHostName

public String getHostName()
Enabled: Gets the host name for this IP address.

If this InetAddress was created with a host name, this host name will be remembered and returned; otherwise, a reverse name lookup will be performed and the result will be returned based on the system configured name lookup service. If a lookup of the name service is required, call getCanonicalHostName.

If there is a security manager, its checkConnect method is first called with the hostname and -1 as its arguments to see if the operation is allowed. If the operation is not allowed, it will return the textual representation of the IP address.

Returns:
the host name for this IP address, or if the operation is not allowed by the security check, the textual representation of the IP address.
See Also:
getCanonicalHostName(), SecurityManager.checkConnect(java.lang.String, int)

getHostName

String getHostName(boolean check)
Returns the hostname for this address. If the host is equal to null, then this address refers to any of the local machine's available network addresses. this is package private so SocketPermission can make calls into here without a security check.

If there is a security manager, this method first calls its checkConnect method with the hostname and -1 as its arguments to see if the calling code is allowed to know the hostname for this IP address, i.e., to connect to the host. If the operation is not allowed, it will return the textual representation of the IP address.

Parameters:
check - make security check if true
Returns:
the host name for this IP address, or if the operation is not allowed by the security check, the textual representation of the IP address.
See Also:
SecurityManager.checkConnect(java.lang.String, int)

getCanonicalHostName

public String getCanonicalHostName()
Enabled: Gets the fully qualified domain name for this IP address. Best effort method, meaning we may not be able to return the FQDN depending on the underlying system configuration.

If there is a security manager, this method first calls its checkConnect method with the hostname and -1 as its arguments to see if the calling code is allowed to know the hostname for this IP address, i.e., to connect to the host. If the operation is not allowed, it will return the textual representation of the IP address.

Returns:
the fully qualified domain name for this IP address, or if the operation is not allowed by the security check, the textual representation of the IP address.
Since:
1.4
See Also:
SecurityManager.checkConnect(java.lang.String, int)

getHostFromNameService

private static String getHostFromNameService(InetAddress addr,
                                             boolean check)
Returns the hostname for this address.

If there is a security manager, this method first calls its checkConnect method with the hostname and -1 as its arguments to see if the calling code is allowed to know the hostname for this IP address, i.e., to connect to the host. If the operation is not allowed, it will return the textual representation of the IP address.

Parameters:
check - make security check if true
Returns:
the host name for this IP address, or if the operation is not allowed by the security check, the textual representation of the IP address.
See Also:
SecurityManager.checkConnect(java.lang.String, int)

getAddress

public byte[] getAddress()
Enabled: Returns the raw IP address of this InetAddress object. The result is in network byte order: the highest order byte of the address is in getAddress()[0].

Returns:
the raw IP address of this object.

getHostAddress

public String getHostAddress()
Enabled: Returns the IP address string in textual presentation.

Returns:
the raw IP address in a string format.
Since:
JDK1.0.2

hashCode

public int hashCode()
Suppressed: Returns a hashcode for this IP address.

Overrides:
hashCode in class Object
Returns:
a hash code value for this IP address.
See Also:
java.lang.Object#equals(java.lang.Object), java.util.Hashtable

equals

public boolean equals(Object obj)
Suppressed: Compares this object against the specified object. The result is true if and only if the argument is not null and it represents the same IP address as this object.

Two instances of InetAddress represent the same IP address if the length of the byte arrays returned by getAddress is the same for both, and each of the array components is the same for the byte arrays.

Overrides:
equals in class Object
Parameters:
obj - the object to compare against.
Returns:
true if the objects are the same; false otherwise.
See Also:
java.net.InetAddress#getAddress()

toString

public String toString()
Suppressed: Converts this IP address to a String. The string returned is of the form: hostname / literal IP address. If the host name is unresolved, no reverse name service loopup is performed. The hostname part will be represented by an empty string.

Overrides:
toString in class Object
Returns:
a string representation of this IP address.

cacheInitIfNeeded

private static void cacheInitIfNeeded()

cacheAddress

private static void cacheAddress(String hostname,
                                 Object address,
                                 boolean success)

cacheAddress

private static void cacheAddress(String hostname,
                                 Object address,
                                 long expiration)

getCachedAddress

private static Object getCachedAddress(String hostname)

getByAddress

public static InetAddress getByAddress(String host,
                                       byte[] addr)
                                throws UnknownHostException
Enabled: Create an InetAddress based on the provided host name and IP address No name service is checked for the validity of the address.

The host name can either be a machine name, such as "java.sun.com", or a textual representation of its IP address.

For host specified in literal IPv6 address, either the form defined in RFC 2732 or the literal IPv6 address format defined in RFC 2373 is accepted.

If addr specifies an IPv4 address an instance of Inet4Address will be returned; otherwise, an instance of Inet6Address will be returned.

IPv4 address byte array must be 4 bytes long and IPv6 byte array must be 16 bytes long

Parameters:
host - the specified host
addr - the raw IP address in network byte order
Returns:
an InetAddress object created from the raw IP address.
UnknownHostException
Since:
1.4

getByName

public static InetAddress getByName(String host)
                             throws UnknownHostException
Enabled: Determines the IP address of a host, given the host's name.

The host name can either be a machine name, such as "java.sun.com", or a textual representation of its IP address. If a literal IP address is supplied, only the validity of the address format is checked.

For host specified in literal IPv6 address, either the form defined in RFC 2732 or the literal IPv6 address format defined in RFC 2373 is accepted.

Parameters:
host - the specified host, or null for the local host.
Returns:
an IP address for the given host name.
UnknownHostException

getAllByName

public static InetAddress[] getAllByName(String host)
                                  throws UnknownHostException
Enabled: Given the name of a host, returns an array of its IP addresses, based on the configured name service on the system.

The host name can either be a machine name, such as "java.sun.com", or a textual representation of its IP address. If a literal IP address is supplied, only the validity of the address format is checked.

For host specified in literal IPv6 address, either the form defined in RFC 2732 or the literal IPv6 address format defined in RFC 2373 is accepted.

If there is a security manager and host is not null and host.length() is not equal to zero, the security manager's checkConnect method is called with the hostname and -1 as its arguments to see if the operation is allowed.

Parameters:
host - the name of the host.
Returns:
an array of all the IP addresses for a given host name.
UnknownHostException
See Also:
SecurityManager.checkConnect(java.lang.String, int)

getAllByName0

private static InetAddress[] getAllByName0(String host)
                                    throws UnknownHostException
UnknownHostException

getAllByName0

static InetAddress[] getAllByName0(String host,
                                   boolean check)
                            throws UnknownHostException
package private so SocketPermission can call it

UnknownHostException

getAddressFromNameService

private static Object getAddressFromNameService(String host)
                                         throws UnknownHostException
UnknownHostException

checkLookupTable

private static Object checkLookupTable(String host)

updateLookupTable

private static void updateLookupTable(String host)

getByAddress

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

This method doesn't block, i.e. no reverse name service lookup is performed.

IPv4 address byte array must be 4 bytes long and IPv6 byte array must be 16 bytes long

Parameters:
addr - the raw IP address in network byte order
Returns:
an InetAddress object created from the raw IP address.
UnknownHostException
Since:
1.4

getLocalHost

public static InetAddress getLocalHost()
                                throws UnknownHostException
Enabled: Returns the local host.

If there is a security manager, its checkConnect method is called with the local host name and -1 as its arguments to see if the operation is allowed. If the operation is not allowed, an InetAddress representing the loopback address is returned.

Returns:
the IP address of the local host.
UnknownHostException
See Also:
SecurityManager.checkConnect(java.lang.String, int)

init

private static void init()
Perform class load-time initializations.


anyLocalAddress

static InetAddress anyLocalAddress()

loadImpl

static Object loadImpl(String implName)


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