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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   * A noop {@link AuthoritativeDnsServerCache} that actually never caches anything.
24   */
25  public final class NoopAuthoritativeDnsServerCache implements AuthoritativeDnsServerCache {
26      public static final NoopAuthoritativeDnsServerCache INSTANCE = new NoopAuthoritativeDnsServerCache();
27  
28      private NoopAuthoritativeDnsServerCache() { }
29  
30      @Override
31      public DnsServerAddressStream get(String hostname) {
32          return null;
33      }
34  
35      @Override
36      public void cache(String hostname, InetSocketAddress address, long originalTtl, EventLoop loop) {
37          // NOOP
38      }
39  
40      @Override
41      public void clear() {
42          // NOOP
43      }
44  
45      @Override
46      public boolean clear(String hostname) {
47          return false;
48      }
49  }