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   /*
    * Copyright 2017 The Netty Project
    *
    * The Netty Project licenses this file to you under the Apache License,
    * version 2.0 (the "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at:
    *
    *   https://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package io.netty.resolver.dns;
  
  import io.netty.channel.ChannelFuture;
  import io.netty.handler.codec.dns.DnsQuestion;
  import io.netty.handler.codec.dns.DnsResponseCode;
  
  import java.net.InetSocketAddress;
  import java.util.List;
  
  final class NoopDnsQueryLifecycleObserver implements DnsQueryLifecycleObserver {
      static final NoopDnsQueryLifecycleObserver INSTANCE = new NoopDnsQueryLifecycleObserver();
  
      private NoopDnsQueryLifecycleObserver() {
      }
  
      @Override
      public void queryWritten(InetSocketAddress dnsServerAddress, ChannelFuture future) {
      }
  
      @Override
      public void queryCancelled(int queriesRemaining) {
      }
  
      @Override
      public DnsQueryLifecycleObserver queryRedirected(List<InetSocketAddress> nameServers) {
          return this;
      }
  
      @Override
      public DnsQueryLifecycleObserver queryCNAMEd(DnsQuestion cnameQuestion) {
          return this;
      }
  
      @Override
      public DnsQueryLifecycleObserver queryNoAnswer(DnsResponseCode code) {
          return this;
      }
  
      @Override
      public void queryFailed(Throwable cause) {
      }
  
      @Override
      public void querySucceed() {
      }
  }