Class InternetDomainName
- java.lang.Object
-
- com.google.common.net.InternetDomainName
-
@GwtCompatible(emulated=true) @Immutable public final class InternetDomainName extends java.lang.Object
An immutable well-formed internet domain name, such ascom
orfoo.co.uk
. Only syntactic analysis is performed; no DNS lookups or other network interactions take place. Thus there is no guarantee that the domain actually exists on the internet.One common use of this class is to determine whether a given string is likely to represent an addressable domain on the web -- that is, for a candidate string
"xxx"
, might browsing to"http://xxx/"
result in a webpage being displayed? In the past, this test was frequently done by determining whether the domain ended with a public suffix but was not itself a public suffix. However, this test is no longer accurate. There are many domains which are both public suffixes and addressable as hosts;"uk.com"
is one example. Using the subset of public suffixes that are registry suffixes, one can get a better result, as only a few registry suffixes are addressable. However, the most useful test to determine if a domain is a plausible web host ishasPublicSuffix()
. This will returntrue
for many domains which (currently) are not hosts, such as"com"
, but given that any public suffix may become a host without warning, it is better to err on the side of permissiveness and thus avoid spurious rejection of valid sites. Of course, to actually determine addressability of any host, clients of this class will need to perform their own DNS lookups.During construction, names are normalized in two ways:
- ASCII uppercase characters are converted to lowercase.
- Unicode dot separators other than the ASCII period (
'.'
) are converted to the ASCII period.
The normalized values will be returned from
toString()
andparts()
, and will be reflected in the result ofequals(Object)
.Internationalized domain names such as
网络.cn
are supported, as are the equivalent IDNA Punycode-encoded versions.- Since:
- 5.0
- Author:
- Catherine Berry
-
-
Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description InternetDomainName
child(java.lang.String leftParts)
Creates and returns a newInternetDomainName
by prepending the argument and a dot to the current name.boolean
equals(java.lang.Object object)
Equality testing is based on the text supplied by the caller, after normalization as described in the class documentation.static InternetDomainName
from(java.lang.String domain)
Returns an instance ofInternetDomainName
after lenient validation.int
hashCode()
boolean
hasParent()
Indicates whether this domain is composed of two or more parts.boolean
hasPublicSuffix()
Indicates whether this domain name ends in a public suffix, including if it is a public suffix itself.boolean
hasRegistrySuffix()
Indicates whether this domain name ends in a registry suffix, including if it is a registry suffix itself.boolean
isPublicSuffix()
Indicates whether this domain name represents a public suffix, as defined by the Mozilla Foundation's Public Suffix List (PSL).boolean
isRegistrySuffix()
Indicates whether this domain name represents a registry suffix, as defined by a subset of the Mozilla Foundation's Public Suffix List (PSL).boolean
isTopDomainUnderRegistrySuffix()
Indicates whether this domain name is composed of exactly one subdomain component followed by a registry suffix.boolean
isTopPrivateDomain()
Indicates whether this domain name is composed of exactly one subdomain component followed by a public suffix.boolean
isUnderPublicSuffix()
Indicates whether this domain name ends in a public suffix, while not being a public suffix itself.boolean
isUnderRegistrySuffix()
Indicates whether this domain name ends in a registry suffix, while not being a registry suffix itself.static boolean
isValid(java.lang.String name)
Indicates whether the argument is a syntactically valid domain name using lenient validation.InternetDomainName
parent()
Returns anInternetDomainName
that is the immediate ancestor of this one; that is, the current domain with the leftmost part removed.ImmutableList<java.lang.String>
parts()
Returns the individual components of this domain name, normalized to all lower case.InternetDomainName
publicSuffix()
Returns the public suffix portion of the domain name, ornull
if no public suffix is present.InternetDomainName
registrySuffix()
Returns the registry suffix portion of the domain name, ornull
if no registry suffix is present.InternetDomainName
topDomainUnderRegistrySuffix()
Returns the portion of this domain name that is one level beneath the registry suffix.InternetDomainName
topPrivateDomain()
Returns the portion of this domain name that is one level beneath the public suffix.java.lang.String
toString()
Returns the domain name, normalized to all lower case.
-
-
-
Method Detail
-
from
@CanIgnoreReturnValue public static InternetDomainName from(java.lang.String domain)
Returns an instance ofInternetDomainName
after lenient validation. Specifically, validation against RFC 3490 ("Internationalizing Domain Names in Applications") is skipped, while validation against RFC 1035 is relaxed in the following ways:- Any part containing non-ASCII characters is considered valid.
- Underscores ('_') are permitted wherever dashes ('-') are permitted.
- Parts other than the final part may start with a digit, as mandated by RFC 1123.
- Parameters:
domain
- A domain name (not IP address)- Throws:
java.lang.IllegalArgumentException
- ifdomain
is not syntactically valid according toisValid(java.lang.String)
- Since:
- 10.0 (previously named
fromLenient
)
-
parts
public ImmutableList<java.lang.String> parts()
Returns the individual components of this domain name, normalized to all lower case. For example, for the domain namemail.google.com
, this method returns the list["mail", "google", "com"]
.
-
isPublicSuffix
public boolean isPublicSuffix()
Indicates whether this domain name represents a public suffix, as defined by the Mozilla Foundation's Public Suffix List (PSL). A public suffix is one under which Internet users can directly register names, such ascom
,co.uk
orpvt.k12.wy.us
. Examples of domain names that are not public suffixes includegoogle.com
,foo.co.uk
, andmyblog.blogspot.com
.Public suffixes are a proper superset of registry suffixes. The list of public suffixes additionally contains privately owned domain names under which Internet users can register subdomains. An example of a public suffix that is not a registry suffix is
blogspot.com
. Note that it is true that all public suffixes have registry suffixes, since domain name registries collectively control all internet domain names.For considerations on whether the public suffix or registry suffix designation is more suitable for your application, see this article.
- Returns:
true
if this domain name appears exactly on the public suffix list- Since:
- 6.0
-
hasPublicSuffix
public boolean hasPublicSuffix()
Indicates whether this domain name ends in a public suffix, including if it is a public suffix itself. For example, returnstrue
forwww.google.com
,foo.co.uk
andcom
, but not forinvalid
orgoogle.invalid
. This is the recommended method for determining whether a domain is potentially an addressable host.Note that this method is equivalent to
hasRegistrySuffix()
because all registry suffixes are public suffixes and all public suffixes have registry suffixes.- Since:
- 6.0
-
publicSuffix
@CheckForNull public InternetDomainName publicSuffix()
Returns the public suffix portion of the domain name, ornull
if no public suffix is present.- Since:
- 6.0
-
isUnderPublicSuffix
public boolean isUnderPublicSuffix()
Indicates whether this domain name ends in a public suffix, while not being a public suffix itself. For example, returnstrue
forwww.google.com
,foo.co.uk
andmyblog.blogspot.com
, but not forcom
,co.uk
,google.invalid
, orblogspot.com
.This method can be used to determine whether it will probably be possible to set cookies on the domain, though even that depends on individual browsers' implementations of cookie controls. See RFC 2109 for details.
- Since:
- 6.0
-
isTopPrivateDomain
public boolean isTopPrivateDomain()
Indicates whether this domain name is composed of exactly one subdomain component followed by a public suffix. For example, returnstrue
forgoogle.com
foo.co.uk
, andmyblog.blogspot.com
, but not forwww.google.com
,co.uk
, orblogspot.com
.This method can be used to determine whether a domain is probably the highest level for which cookies may be set, though even that depends on individual browsers' implementations of cookie controls. See RFC 2109 for details.
- Since:
- 6.0
-
topPrivateDomain
public InternetDomainName topPrivateDomain()
Returns the portion of this domain name that is one level beneath the public suffix. For example, forx.adwords.google.co.uk
it returnsgoogle.co.uk
, sinceco.uk
is a public suffix. Similarly, formyblog.blogspot.com
it returns the same domain,myblog.blogspot.com
, sinceblogspot.com
is a public suffix.If
isTopPrivateDomain()
is true, the current domain name instance is returned.This method can be used to determine the probable highest level parent domain for which cookies may be set, though even that depends on individual browsers' implementations of cookie controls.
- Throws:
java.lang.IllegalStateException
- if this domain does not end with a public suffix- Since:
- 6.0
-
isRegistrySuffix
public boolean isRegistrySuffix()
Indicates whether this domain name represents a registry suffix, as defined by a subset of the Mozilla Foundation's Public Suffix List (PSL). A registry suffix is one under which Internet users can directly register names via a domain name registrar, and have such registrations lawfully protected by internet-governing bodies such as ICANN. Examples of registry suffixes includecom
,co.uk
, andpvt.k12.wy.us
. Examples of domain names that are not registry suffixes includegoogle.com
andfoo.co.uk
.Registry suffixes are a proper subset of public suffixes. The list of public suffixes additionally contains privately owned domain names under which Internet users can register subdomains. An example of a public suffix that is not a registry suffix is
blogspot.com
. Note that it is true that all public suffixes have registry suffixes, since domain name registries collectively control all internet domain names.For considerations on whether the public suffix or registry suffix designation is more suitable for your application, see this article.
- Returns:
true
if this domain name appears exactly on the public suffix list as part of the registry suffix section (labelled "ICANN").- Since:
- 23.3
-
hasRegistrySuffix
public boolean hasRegistrySuffix()
Indicates whether this domain name ends in a registry suffix, including if it is a registry suffix itself. For example, returnstrue
forwww.google.com
,foo.co.uk
andcom
, but not forinvalid
orgoogle.invalid
.Note that this method is equivalent to
hasPublicSuffix()
because all registry suffixes are public suffixes and all public suffixes have registry suffixes.- Since:
- 23.3
-
registrySuffix
@CheckForNull public InternetDomainName registrySuffix()
Returns the registry suffix portion of the domain name, ornull
if no registry suffix is present.- Since:
- 23.3
-
isUnderRegistrySuffix
public boolean isUnderRegistrySuffix()
Indicates whether this domain name ends in a registry suffix, while not being a registry suffix itself. For example, returnstrue
forwww.google.com
,foo.co.uk
andblogspot.com
, but not forcom
,co.uk
, orgoogle.invalid
.- Since:
- 23.3
-
isTopDomainUnderRegistrySuffix
public boolean isTopDomainUnderRegistrySuffix()
Indicates whether this domain name is composed of exactly one subdomain component followed by a registry suffix. For example, returnstrue
forgoogle.com
,foo.co.uk
, andblogspot.com
, but not forwww.google.com
,co.uk
, ormyblog.blogspot.com
.Warning: This method should not be used to determine the probable highest level parent domain for which cookies may be set. Use
topPrivateDomain()
for that purpose.- Since:
- 23.3
-
topDomainUnderRegistrySuffix
public InternetDomainName topDomainUnderRegistrySuffix()
Returns the portion of this domain name that is one level beneath the registry suffix. For example, forx.adwords.google.co.uk
it returnsgoogle.co.uk
, sinceco.uk
is a registry suffix. Similarly, formyblog.blogspot.com
it returnsblogspot.com
, sincecom
is a registry suffix.If
isTopDomainUnderRegistrySuffix()
is true, the current domain name instance is returned.Warning: This method should not be used to determine whether a domain is probably the highest level for which cookies may be set. Use
isTopPrivateDomain()
for that purpose.- Throws:
java.lang.IllegalStateException
- if this domain does not end with a registry suffix- Since:
- 23.3
-
hasParent
public boolean hasParent()
Indicates whether this domain is composed of two or more parts.
-
parent
public InternetDomainName parent()
Returns anInternetDomainName
that is the immediate ancestor of this one; that is, the current domain with the leftmost part removed. For example, the parent ofwww.google.com
isgoogle.com
.- Throws:
java.lang.IllegalStateException
- if the domain has no parent, as determined byhasParent()
-
child
public InternetDomainName child(java.lang.String leftParts)
Creates and returns a newInternetDomainName
by prepending the argument and a dot to the current name. For example,InternetDomainName.from("foo.com").child("www.bar")
returns a newInternetDomainName
with the valuewww.bar.foo.com
. Only lenient validation is performed, as describedhere
.- Throws:
java.lang.NullPointerException
- if leftParts is nulljava.lang.IllegalArgumentException
- if the resulting name is not valid
-
isValid
public static boolean isValid(java.lang.String name)
Indicates whether the argument is a syntactically valid domain name using lenient validation. Specifically, validation against RFC 3490 ("Internationalizing Domain Names in Applications") is skipped.The following two code snippets are equivalent:
domainName = InternetDomainName.isValid(name) ? InternetDomainName.from(name) : DEFAULT_DOMAIN;
try { domainName = InternetDomainName.from(name); } catch (IllegalArgumentException e) { domainName = DEFAULT_DOMAIN; }
- Since:
- 8.0 (previously named
isValidLenient
)
-
toString
public java.lang.String toString()
Returns the domain name, normalized to all lower case.- Overrides:
toString
in classjava.lang.Object
-
equals
public boolean equals(@CheckForNull java.lang.Object object)
Equality testing is based on the text supplied by the caller, after normalization as described in the class documentation. For example, a non-ASCII Unicode domain name and the Punycode version of the same domain name would not be considered equal.- Overrides:
equals
in classjava.lang.Object
-
hashCode
public int hashCode()
- Overrides:
hashCode
in classjava.lang.Object
-
-