InetSocketAddress

public class InetSocketAddress extends SocketAddress

This class implements an IP Socket Address (IP address + port number) It can also be a pair (hostname + port number), in which case an attempt will be made to resolve the hostname. If resolution fails then the address is said to be unresolved but can still be used on some circumstances like connecting through a proxy.

It provides an immutable object used by sockets for binding, connecting, or as returned values.

The wildcard is a special local IP address. It usually means "any" and can only be used for bind operations.

Public Constructor Summary

InetSocketAddress(int port)
Creates a socket address where the IP address is the wildcard address and the port number a specified value.
InetSocketAddress(InetAddress addr, int port)
Creates a socket address from an IP address and a port number.
InetSocketAddress(String hostname, int port)
Creates a socket address from a hostname and a port number.

Public Method Summary

static InetSocketAddress
createUnresolved(String host, int port)
Creates an unresolved socket address from a hostname and a port number.
final boolean
equals(Object obj)
Compares this object against the specified object.
final InetAddress
getAddress()
Gets the InetAddress.
final String
getHostName()
Gets the hostname.
final String
getHostString()
Returns the hostname, or the String form of the address if it doesn't have a hostname (it was created using a literal).
final int
getPort()
Gets the port number.
final int
hashCode()
Returns a hashcode for this socket address.
final boolean
isUnresolved()
Checks whether the address has been resolved or not.
String
toString()
Constructs a string representation of this InetSocketAddress.

Inherited Method Summary

Public Constructors

public InetSocketAddress (int port)

Creates a socket address where the IP address is the wildcard address and the port number a specified value.

A valid port value is between 0 and 65535. A port number of zero will let the system pick up an ephemeral port in a bind operation.

Parameters
port The port number
Throws
IllegalArgumentException if the port parameter is outside the specified range of valid port values.

public InetSocketAddress (InetAddress addr, int port)

Creates a socket address from an IP address and a port number.

A valid port value is between 0 and 65535. A port number of zero will let the system pick up an ephemeral port in a bind operation.

A null address will assign the wildcard address.

Parameters
addr The IP address
port The port number
Throws
IllegalArgumentException if the port parameter is outside the specified range of valid port values.

public InetSocketAddress (String hostname, int port)

Creates a socket address from a hostname and a port number.

An attempt will be made to resolve the hostname into an InetAddress. If that attempt fails, the address will be flagged as unresolved.

If there is a security manager, its checkConnect method is called with the host name as its argument to check the permissiom to resolve it. This could result in a SecurityException.

A valid port value is between 0 and 65535. A port number of zero will let the system pick up an ephemeral port in a bind operation.

Parameters
hostname the Host name
port The port number
Throws
IllegalArgumentException if the port parameter is outside the range of valid port values, or if the hostname parameter is null.
SecurityException if a security manager is present and permission to resolve the host name is denied.
See Also

Public Methods

public static InetSocketAddress createUnresolved (String host, int port)

Creates an unresolved socket address from a hostname and a port number.

No attempt will be made to resolve the hostname into an InetAddress. The address will be flagged as unresolved.

A valid port value is between 0 and 65535. A port number of zero will let the system pick up an ephemeral port in a bind operation.

Parameters
host the Host name
port The port number
Returns
  • a InetSocketAddress representing the unresolved socket address
Throws
IllegalArgumentException if the port parameter is outside the range of valid port values, or if the hostname parameter is null.
See Also

public final boolean equals (Object obj)

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 address as this object.

Two instances of InetSocketAddress represent the same address if both the InetAddresses (or hostnames if it is unresolved) and port numbers are equal. If both addresses are unresolved, then the hostname & the port number are compared. Note: Hostnames are case insensitive. e.g. "FooBar" and "foobar" are considered equal.

Parameters
obj the object to compare against.
Returns
  • true if the objects are the same; false otherwise.

public final InetAddress getAddress ()

Gets the InetAddress.

Returns
  • the InetAdress or null if it is unresolved.

public final String getHostName ()

Gets the hostname. Note: This method may trigger a name service reverse lookup if the address was created with a literal IP address.

Returns
  • the hostname part of the address.

public final String getHostString ()

Returns the hostname, or the String form of the address if it doesn't have a hostname (it was created using a literal). This has the benefit of not attempting a reverse lookup.

Returns
  • the hostname, or String representation of the address.

public final int getPort ()

Gets the port number.

Returns
  • the port number.

public final int hashCode ()

Returns a hashcode for this socket address.

Returns
  • a hash code value for this socket address.

public final boolean isUnresolved ()

Checks whether the address has been resolved or not.

Returns
  • true if the hostname couldn't be resolved into an InetAddress.

public String toString ()

Constructs a string representation of this InetSocketAddress. This String is constructed by calling toString() on the InetAddress and concatenating the port number (with a colon). If the address is unresolved then the part before the colon will only contain the hostname.

Returns
  • a string representation of this object.