/*
 * Copyright (c) 2014 Red Hat, Inc. and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 * which is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 */

/**
 * == DNS client
 *
 * Often you will find yourself in situations where you need to obtain DNS informations in an asynchronous fashion.
 * Unfortunally this is not possible with the API that is shipped with the Java Virtual Machine itself. Because of
 * this Vert.x offers it's own API for DNS resolution which is fully asynchronous.
 *
 * To obtain a DnsClient instance you will create a new via the Vertx instance.
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example1}
 * ----
 *
 * You can also create the client with options and configure the query timeout.
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example1_}
 * ----
 *
 * Creating the client with no arguments or omitting the server address will use the address of the server used internally
 * for non blocking address resolution.
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example1__}
 * ----
 *
 * === lookup
 *
 * Try to lookup the A (ipv4) or AAAA (ipv6) record for a given name. The first which is returned will be used,
 * so it behaves the same way as you may be used from when using "nslookup" on your operation system.
 *
 * To lookup the A / AAAA record for "vertx.io" you would typically use it like:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example2}
 * ----
 *
 * === lookup4
 *
 * Try to lookup the A (ipv4) record for a given name. The first which is returned will be used, so it behaves
 * the same way as you may be used from when using "nslookup" on your operation system.
 *
 * To lookup the A record for "vertx.io" you would typically use it like:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example3}
 * ----
 *
 * === lookup6
 *
 * Try to lookup the AAAA (ipv6) record for a given name. The first which is returned will be used, so it behaves the
 * same way as you may be used from when using "nslookup" on your operation system.
 *
 * To lookup the A record for "vertx.io" you would typically use it like:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example4}
 * ----
 *
 * === resolveA
 *
 * Try to resolve all A (ipv4) records for a given name. This is quite similar to using "dig" on unix like operation
 * systems.
 *
 * To lookup all the A records for "vertx.io" you would typically do:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example5}
 * ----
 *
 * === resolveAAAA
 *
 * Try to resolve all AAAA (ipv6) records for a given name. This is quite similar to using "dig" on unix like
 * operation systems.
 *
 * To lookup all the AAAAA records for "vertx.io" you would typically do:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example6}
 * ----
 *
 * === resolveCNAME
 *
 * Try to resolve all CNAME records for a given name. This is quite similar to using "dig" on unix like operation
 * systems.
 *
 * To lookup all the CNAME records for "vertx.io" you would typically do:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example7}
 * ----
 *
 * === resolveMX
 *
 * Try to resolve all MX records for a given name. The MX records are used to define which Mail-Server accepts
 * emails for a given domain.
 *
 * To lookup all the MX records for "vertx.io" you would typically do:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example8}
 * ----
 *
 * Be aware that the List will contain the {@link io.vertx.core.dns.MxRecord} sorted by the priority of them, which
 * means MX records with smaller priority coming first in the List.
 *
 * The {@link io.vertx.core.dns.MxRecord} allows you to access the priority and the name of the MX record by offer methods for it like:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example9}
 * ----
 *
 * === resolveTXT
 *
 * Try to resolve all TXT records for a given name. TXT records are often used to define extra informations for a domain.
 *
 * To resolve all the TXT records for "vertx.io" you could use something along these lines:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example10}
 * ----
 *
 * === resolveNS
 *
 * Try to resolve all NS records for a given name. The NS records specify which DNS Server hosts the DNS informations
 * for a given domain.
 *
 * To resolve all the NS records for "vertx.io" you could use something along these lines:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example11}
 * ----
 *
 * === resolveSRV
 *
 * Try to resolve all SRV records for a given name. The SRV records are used to define extra informations like port and
 * hostname of services. Some protocols need this extra informations.
 *
 * To lookup all the SRV records for "vertx.io" you would typically do:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example12}
 * ----
 *
 * Be aware that the List will contain the SrvRecords sorted by the priority of them, which means SrvRecords
 * with smaller priority coming first in the List.
 *
 * The {@link io.vertx.core.dns.SrvRecord} allows you to access all informations contained in the SRV record itself:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example13}
 * ----
 *
 * Please refer to the API docs for the exact details.
 *
 * === resolvePTR
 *
 * Try to resolve the PTR record for a given name. The PTR record maps an ipaddress to a name.
 *
 * To resolve the PTR record for the ipaddress 10.0.0.1 you would use the PTR notion of "1.0.0.10.in-addr.arpa"
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example14}
 * ----
 *
 * === reverseLookup
 *
 * Try to do a reverse lookup for an ipaddress. This is basically the same as resolve a PTR record, but allows you to
 * just pass in the ipaddress and not a valid PTR query string.
 *
 * To do a reverse lookup for the ipaddress 10.0.0.1 do something similar like this:
 *
 * [source,$lang]
 * ----
 * {@link examples.DNSExamples#example15}
 * ----
 *
 * include::override/dns.adoc[]
 */
package io.vertx.core.dns;

