1 /* 2 * Copyright 2018 The Netty Project 3 * 4 * The Netty Project licenses this file to you under the Apache License, 5 * version 2.0 (the "License"); you may not use this file except in compliance 6 * with the License. You may obtain a copy of the License at: 7 * 8 * https://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 13 * License for the specific language governing permissions and limitations 14 * under the License. 15 */ 16 package io.netty.resolver.dns; 17 18 import io.netty.channel.EventLoop; 19 20 import java.net.InetSocketAddress; 21 22 /** 23 * Cache which stores the nameservers that should be used to resolve a specific hostname. 24 */ 25 public interface AuthoritativeDnsServerCache { 26 27 /** 28 * Returns the cached nameservers that should be used to resolve the given hostname. The returned 29 * {@link DnsServerAddressStream} may contain unresolved {@link InetSocketAddress}es that will be resolved 30 * when needed while resolving other domain names. 31 * 32 * @param hostname the hostname 33 * @return the cached entries or an {@code null} if none. 34 */ 35 DnsServerAddressStream get(String hostname); 36 37 /** 38 * Caches a nameserver that should be used to resolve the given hostname. 39 * 40 * @param hostname the hostname 41 * @param address the nameserver address (which may be unresolved). 42 * @param originalTtl the TTL as returned by the DNS server 43 * @param loop the {@link EventLoop} used to register the TTL timeout 44 */ 45 void cache(String hostname, InetSocketAddress address, long originalTtl, EventLoop loop); 46 47 /** 48 * Clears all cached nameservers. 49 * 50 * @see #clear(String) 51 */ 52 void clear(); 53 54 /** 55 * Clears the cached nameservers for the specified hostname. 56 * 57 * @return {@code true} if and only if there was an entry for the specified host name in the cache and 58 * it has been removed by this method 59 */ 60 boolean clear(String hostname); 61 }