How to use

topDomainUnderRegistrySuffix

method

in

com.google.common.net.InternetDomainName

/**
 * Extract the domain name (without subdomain). The Guava {@link InternetDomainName} implementation
 * provides a method to correctly handle this (and handles special cases for TLDs with multiple
 * names. eg. for lb01.store.amazon.co.uk, only amazon.co.uk would be extracted).
 * It uses https://publicsuffix.org behind the scenes.
 * <p>
 * Some domains (eg. completely randomly defined PTR domains) are not considered to have a public
 * suffix according to Guava. For those, the only option is to manually extract the domain with
 * string operations. This should be a rare case.
 */
public static void parseReverseLookupDomain(PtrDnsAnswer.Builder dnsAnswerBuilder, String hostname) {
  dnsAnswerBuilder.fullDomain(hostname);
  final InternetDomainName internetDomainName = InternetDomainName.from(hostname);
  if (internetDomainName.hasPublicSuffix()) {
    // Use Guava to extract domain name.
    final InternetDomainName topDomainName = internetDomainName.topDomainUnderRegistrySuffix();
    dnsAnswerBuilder.domain(topDomainName.toString());
  } else {
    /* Manually extract domain name.
     * Eg. for hostname test.some-domain.com, only some-domain.com will be extracted. */
    String[] split = hostname.split("\\.");
    if (split.length > 1) {
      dnsAnswerBuilder.domain(split[split.length - 2] + "." + split[split.length - 1]);
    } else if (split.length == 1) {
      dnsAnswerBuilder.domain(hostname); // Domain is a single word with no dots.
    } else {
      dnsAnswerBuilder.domain(""); // Domain is blank.
    }
  }
}

public void testRegistrySuffixMultipleUnders() {
 // PSL has both *.uk and *.sch.uk; the latter should win.
 // See http://code.google.com/p/guava-libraries/issues/detail?id=1176
 InternetDomainName domain = InternetDomainName.from("www.essex.sch.uk");
 assertTrue(domain.hasRegistrySuffix());
 assertEquals("essex.sch.uk", domain.registrySuffix().toString());
 assertEquals("www.essex.sch.uk", domain.topDomainUnderRegistrySuffix().toString());
}

/**
 * Extract the domain name (without subdomain). The Guava {@link InternetDomainName} implementation
 * provides a method to correctly handle this (and handles special cases for TLDs with multiple
 * names. eg. for lb01.store.amazon.co.uk, only amazon.co.uk would be extracted).
 * It uses https://publicsuffix.org behind the scenes.
 * <p>
 * Some domains (eg. completely randomly defined PTR domains) are not considered to have a public
 * suffix according to Guava. For those, the only option is to manually extract the domain with
 * string operations. This should be a rare case.
 */
public static void parseReverseLookupDomain(PtrDnsAnswer.Builder dnsAnswerBuilder, String hostname) {
  dnsAnswerBuilder.fullDomain(hostname);
  final InternetDomainName internetDomainName = InternetDomainName.from(hostname);
  if (internetDomainName.hasPublicSuffix()) {
    // Use Guava to extract domain name.
    final InternetDomainName topDomainName = internetDomainName.topDomainUnderRegistrySuffix();
    dnsAnswerBuilder.domain(topDomainName.toString());
  } else {
    /* Manually extract domain name.
     * Eg. for hostname test.some-domain.com, only some-domain.com will be extracted. */
    String[] split = hostname.split("\\.");
    if (split.length > 1) {
      dnsAnswerBuilder.domain(split[split.length - 2] + "." + split[split.length - 1]);
    } else if (split.length == 1) {
      dnsAnswerBuilder.domain(hostname); // Domain is a single word with no dots.
    } else {
      dnsAnswerBuilder.domain(""); // Domain is blank.
    }
  }
}

public void testRegistrySuffixMultipleUnders() {
 // PSL has both *.uk and *.sch.uk; the latter should win.
 // See http://code.google.com/p/guava-libraries/issues/detail?id=1176
 InternetDomainName domain = InternetDomainName.from("www.essex.sch.uk");
 assertTrue(domain.hasRegistrySuffix());
 assertEquals("essex.sch.uk", domain.registrySuffix().toString());
 assertEquals("www.essex.sch.uk", domain.topDomainUnderRegistrySuffix().toString());
}