org.xbill.DNS
Class Name

java.lang.Object
  org.xbill.DNS.Name

All Implemented Interfaces:

Comparable

public class Name
extends Object
implements Comparable

A representation of a domain name. It may either be absolute (fully qualified) or relative.

Author:

Brian Wellington

Field Summary

static Name	empty The root name
static Name	root The root name

Constructor Summary

Name(byte[] b)
Create a new name from DNS wire format

Name(DNSInput in)
Create a new name from DNS a wire format message

Name(Name src, int n)
Create a new name by removing labels from the beginning of an existing Name

Name(String s)
Create a new name from a string.

Name(String s, Name origin)
Create a new name from a string and an origin.

Method Summary

int	compareTo(Object o) Compares this Name to another Object.
static Name	concatenate(Name prefix, Name suffix) Creates a new name by concatenating two existing names.
boolean	equals(Object arg) Are these two Names equivalent?
static Name	fromConstantString(String s) Create a new name from a constant string.
Name	fromDNAME(DNAMERecord dname) Generates a new Name to be used when following a DNAME.
static Name	fromString(String s) Create a new name from a string.
static Name	fromString(String s, Name origin) Create a new name from a string and an origin.
byte[]	getLabel(int n) Retrieve the nth label of a Name.
String	getLabelString(int n) Convert the nth label in a Name to a String
int	hashCode() Computes a hashcode based on the value
boolean	isAbsolute() Is this name absolute?
boolean	isWild() Is this name a wildcard?
int	labels() The number of labels in the name.
short	length() The length of the name.
Name	relativize(Name origin) If this name is a subdomain of origin, return a new name relative to origin with the same value.
boolean	subdomain(Name domain) Is the current Name a subdomain of the specified name?
String	toString() Convert a Name to a String
byte[]	toWire() Emit a Name in DNS wire format
void	toWire(DNSOutput out, Compression c) Emit a Name in DNS wire format
void	toWire(DNSOutput out, Compression c, boolean canonical) Emit a Name in DNS wire format
byte[]	toWireCanonical() Emit a Name in canonical DNS wire format (all lowercase)
void	toWireCanonical(DNSOutput out) Emit a Name in canonical DNS wire format (all lowercase)
Name	wild(int n) Generates a new Name with the first n labels replaced by a wildcard

Methods inherited from class java.lang.Object

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

Field Detail

root

public static final Name root

The root name

empty

public static final Name empty

The root name

Constructor Detail

Name

public Name(String s,
            Name origin)
     throws TextParseException

Create a new name from a string and an origin. This does not automatically make the name absolute; it will be absolute if it has a trailing dot or an absolute origin is appended.

Parameters:

s - The string to be converted

origin - If the name is not absolute, the origin to be appended.

Throws:

TextParseException - The name is invalid.

Name

public Name(String s)
     throws TextParseException

Create a new name from a string. This does not automatically make the name absolute; it will be absolute if it has a trailing dot.

Parameters:

s - The string to be converted

Throws:

TextParseException - The name is invalid.

Name

public Name(DNSInput in)
     throws WireParseException

Create a new name from DNS a wire format message

Parameters:

in - A stream containing the DNS message which is currently positioned at the start of the name to be read.

Throws:

WireParseException

Name

public Name(byte[] b)
     throws IOException

Create a new name from DNS wire format

Parameters:

b - A byte array containing the wire format of the name.

Throws:

IOException

Name

public Name(Name src,
            int n)

Create a new name by removing labels from the beginning of an existing Name

Parameters:

src - An existing Name

n - The number of labels to remove from the beginning in the copy

Method Detail

fromString

public static Name fromString(String s,
                              Name origin)
                       throws TextParseException

Create a new name from a string and an origin. This does not automatically make the name absolute; it will be absolute if it has a trailing dot or an absolute origin is appended. This is identical to the constructor, except that it will avoid creating new objects in some cases.

Parameters:

s - The string to be converted

origin - If the name is not absolute, the origin to be appended.

Throws:

TextParseException - The name is invalid.

fromString

public static Name fromString(String s)
                       throws TextParseException

Create a new name from a string. This does not automatically make the name absolute; it will be absolute if it has a trailing dot. This is identical to the constructor, except that it will avoid creating new objects in some cases.

Parameters:

s - The string to be converted

Throws:

TextParseException - The name is invalid.

fromConstantString

public static Name fromConstantString(String s)

Create a new name from a constant string. This should only be used when the name is known to be good - that is, when it is constant.

Parameters:

s - The string to be converted

Throws:

IllegalArgumentException - The name is invalid.

concatenate

public static Name concatenate(Name prefix,
                               Name suffix)
                        throws NameTooLongException

Creates a new name by concatenating two existing names.

Parameters:

prefix - The prefix name.

suffix - The suffix name.

Returns:

The concatenated name.

Throws:

NameTooLongException - The name is too long.

relativize

public Name relativize(Name origin)

If this name is a subdomain of origin, return a new name relative to origin with the same value. Otherwise, return the existing name.

Parameters:

origin - The origin to remove.

Returns:

The possibly relativized name.

wild

public Name wild(int n)

Generates a new Name with the first n labels replaced by a wildcard

Returns:

The wildcard name

fromDNAME

public Name fromDNAME(DNAMERecord dname)
               throws NameTooLongException

Generates a new Name to be used when following a DNAME.

Parameters:

dname - The DNAME record to follow.

Returns:

The constructed name.

Throws:

NameTooLongException - The resulting name is too long.

isWild

public boolean isWild()

Is this name a wildcard?

isAbsolute

public boolean isAbsolute()

Is this name absolute?

length

public short length()

The length of the name.

labels

public int labels()

The number of labels in the name.

subdomain

public boolean subdomain(Name domain)

Is the current Name a subdomain of the specified name?

toString

public String toString()

Convert a Name to a String

Overrides:

toString in class Object

Returns:

The representation of this name as a (printable) String.

getLabel

public byte[] getLabel(int n)

Retrieve the nth label of a Name. This makes a copy of the label; changing this does not change the Name.

Parameters:

n - The label to be retrieved. The first label is 0.

getLabelString

public String getLabelString(int n)

Convert the nth label in a Name to a String

Parameters:

n - The label to be converted to a (printable) String. The first label is 0.

toWire

public void toWire(DNSOutput out,
                   Compression c)

Emit a Name in DNS wire format

Parameters:

out - The output stream containing the DNS message.

c - The compression context, or null of no compression is desired.

Throws:

IllegalArgumentException - The name is not absolute.

toWire

public byte[] toWire()

Emit a Name in DNS wire format

Throws:

IllegalArgumentException - The name is not absolute.

toWireCanonical

public void toWireCanonical(DNSOutput out)

Emit a Name in canonical DNS wire format (all lowercase)

Parameters:

out - The output stream to which the message is written.

toWireCanonical

public byte[] toWireCanonical()

Emit a Name in canonical DNS wire format (all lowercase)

Returns:

The canonical form of the name.

toWire

public void toWire(DNSOutput out,
                   Compression c,
                   boolean canonical)

Emit a Name in DNS wire format

Parameters:

out - The output stream containing the DNS message.

c - The compression context, or null of no compression is desired.

canonical - If true, emit the name in canonicalized form (all lowercase).

Throws:

IllegalArgumentException - The name is not absolute.

equals

public boolean equals(Object arg)

Are these two Names equivalent?

Overrides:

equals in class Object

hashCode

public int hashCode()

Computes a hashcode based on the value

Overrides:

hashCode in class Object

compareTo

public int compareTo(Object o)

Compares this Name to another Object.

Specified by:

compareTo in interface Comparable

Parameters:

o - The Object to be compared.

Returns:

The value 0 if the argument is a name equivalent to this name; a value less than 0 if the argument is less than this name in the canonical ordering, and a value greater than 0 if the argument is greater than this name in the canonical ordering.

Throws:

ClassCastException - if the argument is not a Name.