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.netty5.resolver.dns;
17
18 import io.netty5.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 }