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1   /*
2    * Copyright 2017 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    *   http://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.ChannelFuture;
19  import io.netty.handler.codec.dns.DnsQuestion;
20  import io.netty.handler.codec.dns.DnsResponseCode;
21  
22  import java.net.InetSocketAddress;
23  import java.util.List;
24  
25  final class NoopDnsQueryLifecycleObserver implements DnsQueryLifecycleObserver {
26      static final NoopDnsQueryLifecycleObserver INSTANCE = new NoopDnsQueryLifecycleObserver();
27  
28      private NoopDnsQueryLifecycleObserver() {
29      }
30  
31      @Override
32      public void queryWritten(InetSocketAddress dnsServerAddress, ChannelFuture future) {
33      }
34  
35      @Override
36      public void queryCancelled(int queriesRemaining) {
37      }
38  
39      @Override
40      public DnsQueryLifecycleObserver queryRedirected(List<InetSocketAddress> nameServers) {
41          return this;
42      }
43  
44      @Override
45      public DnsQueryLifecycleObserver queryCNAMEd(DnsQuestion cnameQuestion) {
46          return this;
47      }
48  
49      @Override
50      public DnsQueryLifecycleObserver queryNoAnswer(DnsResponseCode code) {
51          return this;
52      }
53  
54      @Override
55      public void queryFailed(Throwable cause) {
56      }
57  
58      @Override
59      public void querySucceed() {
60      }
61  }