Module java.base

Package java.net.spi

Interface InetAddressResolver

public interface InetAddressResolver

This interface defines operations for looking up host names and IP addresses. InetAddress delegates all lookup operations to the system-wide resolver.

The system-wide resolver can be customized by deploying an implementation of InetAddressResolverProvider.

Since:

18

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static final class	InetAddressResolver.LookupPolicy	A LookupPolicy object describes characteristics that can be applied to a lookup operation.

Method Summary

Modifier and Type	Method	Description
String	lookupByAddress(byte[] addr)	Lookup the host name corresponding to the raw IP address provided.
Stream<InetAddress>	lookupByName(String host, InetAddressResolver.LookupPolicy lookupPolicy)	Given the name of a host, returns a stream of IP addresses of the requested address family associated with a provided hostname.

Method Details

lookupByName

Stream<InetAddress> lookupByName(String host,
 InetAddressResolver.LookupPolicy lookupPolicy)
                          throws UnknownHostException

Given the name of a host, returns a stream of IP addresses of the requested address family associated with a provided hostname.

host should be a machine name, such as "www.example.com", not a textual representation of its IP address. No validation is performed on the given host name: if a textual representation is supplied, the name resolution is likely to fail and UnknownHostException may be thrown.

The address family type and addresses order are specified by the LookupPolicy instance. Lookup operation characteristics could be acquired with InetAddressResolver.LookupPolicy.characteristics(). If InetAddressResolver.LookupPolicy.IPV4 and InetAddressResolver.LookupPolicy.IPV6 characteristics provided then this method returns addresses of both IPV4 and IPV6 families.

Parameters:

host - the specified hostname

lookupPolicy - the address lookup policy

Returns:

a stream of IP addresses for the requested host

Throws:

NullPointerException - if either parameter is null

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

See Also:

• InetAddressResolver.LookupPolicy

lookupByAddress

String lookupByAddress(byte[] addr)
                throws UnknownHostException

Lookup the host name corresponding to the raw IP address provided.

addr argument is in network byte order: the highest order byte of the address is in addr[0].

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

Parameters:

addr - byte array representing a raw IP address

Returns:

String representing the host name mapping

Throws:

UnknownHostException - if no host name is found for the specified IP address

IllegalArgumentException - if the length of the provided byte array doesn't correspond to a valid IP address length

NullPointerException - if addr is null