io.milton.dns.record

Class SimpleResolver

java.lang.Object

io.milton.dns.record.SimpleResolver

All Implemented Interfaces:

Resolver

public class SimpleResolver
extends Object
implements Resolver

An implementation of Resolver that sends one query to one server. SimpleResolver handles TCP retries, transaction security (TSIG), and EDNS 0.

Author:

Brian Wellington

See Also:

Resolver, TSIG, OPTRecord

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_EDNS_PAYLOADSIZE The default EDNS payload size
static int	DEFAULT_PORT The default port to send queries to

Constructor Summary

Constructors

Constructor and Description
SimpleResolver() Creates a SimpleResolver.
SimpleResolver(String hostname) Creates a SimpleResolver that will query the specified host

Method Summary

Modifier and Type	Method and Description
Message	send(Message query) Sends a message to a single server and waits for a response.
Object	sendAsync(Message query, ResolverListener listener) Asynchronously sends a message to a single server, registering a listener to receive a callback on success or exception.
void	setAddress(InetAddress addr) Sets the address of the server to communicate with (on the default DNS port)
void	setAddress(InetSocketAddress addr) Sets the address of the server to communicate with.
static void	setDefaultResolver(String hostname) Sets the default host (initially localhost) to query
void	setEDNS(int level) Sets the EDNS version used on outgoing messages.
void	setEDNS(int level, int payloadSize, int flags, List options) Sets the EDNS information on outgoing messages.
void	setIgnoreTruncation(boolean flag) Sets whether truncated responses will be ignored.
void	setLocalAddress(InetAddress addr) Sets the local address to bind to when sending messages.
void	setLocalAddress(InetSocketAddress addr) Sets the local address to bind to when sending messages.
void	setPort(int port) Sets the port to communicate with on the server
void	setTCP(boolean flag) Sets whether TCP connections will be sent by default
void	setTimeout(int secs) Sets the amount of time to wait for a response before giving up.
void	setTimeout(int secs, int msecs) Sets the amount of time to wait for a response before giving up.
void	setTSIGKey(TSIG key) Specifies the TSIG key that messages will be signed with

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_PORT

public static final int DEFAULT_PORT

The default port to send queries to

See Also:

Constant Field Values

DEFAULT_EDNS_PAYLOADSIZE

public static final int DEFAULT_EDNS_PAYLOADSIZE

The default EDNS payload size

See Also:

Constant Field Values

Constructor Detail

SimpleResolver

public SimpleResolver(String hostname)
               throws UnknownHostException

Creates a SimpleResolver that will query the specified host

Throws:

UnknownHostException - Failure occurred while finding the host

SimpleResolver

public SimpleResolver()
               throws UnknownHostException

Creates a SimpleResolver. The host to query is either found by using ResolverConfig, or the default host is used.

Throws:

UnknownHostException - Failure occurred while finding the host

See Also:

ResolverConfig

Method Detail

setDefaultResolver

public static void setDefaultResolver(String hostname)

Sets the default host (initially localhost) to query

setPort

public void setPort(int port)

Description copied from interface: Resolver

Sets the port to communicate with on the server

Specified by:

setPort in interface Resolver

Parameters:

port - The port to send messages to

setAddress

public void setAddress(InetSocketAddress addr)

Sets the address of the server to communicate with.

Parameters:

addr - The address of the DNS server

setAddress

public void setAddress(InetAddress addr)

Sets the address of the server to communicate with (on the default DNS port)

Parameters:

addr - The address of the DNS server

setLocalAddress

public void setLocalAddress(InetSocketAddress addr)

Sets the local address to bind to when sending messages.

Parameters:

addr - The local address to send messages from.

setLocalAddress

public void setLocalAddress(InetAddress addr)

Sets the local address to bind to when sending messages. A random port will be used.

Parameters:

addr - The local address to send messages from.

setTCP

public void setTCP(boolean flag)

Description copied from interface: Resolver

Sets whether TCP connections will be sent by default

Specified by:

setTCP in interface Resolver

Parameters:

flag - Indicates whether TCP connections are made

setIgnoreTruncation

public void setIgnoreTruncation(boolean flag)

Description copied from interface: Resolver

Sets whether truncated responses will be ignored. If not, a truncated response over UDP will cause a retransmission over TCP.

Specified by:

setIgnoreTruncation in interface Resolver

Parameters:

flag - Indicates whether truncated responses should be ignored.

setEDNS

public void setEDNS(int level,
                    int payloadSize,
                    int flags,
                    List options)

Description copied from interface: Resolver

Sets the EDNS information on outgoing messages.

Specified by:

setEDNS in interface Resolver

Parameters:

level - The EDNS level to use. 0 indicates EDNS0 and -1 indicates no EDNS.

payloadSize - The maximum DNS packet size that this host is capable of receiving over UDP. If 0 is specified, the default (1280) is used.

flags - EDNS extended flags to be set in the OPT record.

options - EDNS options to be set in the OPT record, specified as a List of OPTRecord.Option elements.

See Also:

OPTRecord

setEDNS

public void setEDNS(int level)

Description copied from interface: Resolver

Sets the EDNS version used on outgoing messages.

Specified by:

setEDNS in interface Resolver

Parameters:

level - The EDNS level to use. 0 indicates EDNS0 and -1 indicates no EDNS.

setTSIGKey

public void setTSIGKey(TSIG key)

Description copied from interface: Resolver

Specifies the TSIG key that messages will be signed with

Specified by:

setTSIGKey in interface Resolver

Parameters:

key - The key

setTimeout

public void setTimeout(int secs,
                       int msecs)

Description copied from interface: Resolver

Sets the amount of time to wait for a response before giving up.

Specified by:

setTimeout in interface Resolver

Parameters:

secs - The number of seconds to wait.

msecs - The number of milliseconds to wait.

setTimeout

public void setTimeout(int secs)

Description copied from interface: Resolver

Sets the amount of time to wait for a response before giving up.

Specified by:

setTimeout in interface Resolver

Parameters:

secs - The number of seconds to wait.

send

public Message send(Message query)
             throws IOException

Sends a message to a single server and waits for a response. No checking is done to ensure that the response is associated with the query.

Specified by:

send in interface Resolver

Parameters:

query - The query to send.

Returns:

The response.

Throws:

IOException - An error occurred while sending or receiving.

sendAsync

public Object sendAsync(Message query,
                        ResolverListener listener)

Asynchronously sends a message to a single server, registering a listener to receive a callback on success or exception. Multiple asynchronous lookups can be performed in parallel. Since the callback may be invoked before the function returns, external synchronization is necessary.

Specified by:

sendAsync in interface Resolver

Parameters:

query - The query to send

listener - The object containing the callbacks.

Returns:

An identifier, which is also a parameter in the callback