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 /**
21 * A cache for {@code CNAME}s.
22 */
23 public interface DnsCnameCache {
24
25 /**
26 * Returns the cached cname for the given hostname.
27 *
28 * @param hostname the hostname
29 * @return the cached entries or an {@code null} if none.
30 */
31 String get(String hostname);
32
33 /**
34 * Caches a cname entry that should be used for the given hostname.
35 *
36 * @param hostname the hostname
37 * @param cname the cname mapping.
38 * @param originalTtl the TTL as returned by the DNS server
39 * @param loop the {@link EventLoop} used to register the TTL timeout
40 */
41 void cache(String hostname, String cname, long originalTtl, EventLoop loop);
42
43 /**
44 * Clears all cached nameservers.
45 *
46 * @see #clear(String)
47 */
48 void clear();
49
50 /**
51 * Clears the cached nameservers for the specified hostname.
52 *
53 * @return {@code true} if and only if there was an entry for the specified host name in the cache and
54 * it has been removed by this method
55 */
56 boolean clear(String hostname);
57 }