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1   /*
2    * Copyright 2015 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  
17  package io.netty.resolver;
18  
19  import io.netty.util.internal.SocketUtils;
20  import io.netty.util.concurrent.EventExecutor;
21  import io.netty.util.concurrent.Promise;
22  
23  import java.net.InetAddress;
24  import java.net.UnknownHostException;
25  import java.util.Arrays;
26  import java.util.List;
27  
28  /**
29   * A {@link InetNameResolver} that resolves using JDK's built-in domain name lookup mechanism.
30   * Note that this resolver performs a blocking name lookup from the caller thread.
31   */
32  public class DefaultNameResolver extends InetNameResolver {
33  
34      public DefaultNameResolver(EventExecutor executor) {
35          super(executor);
36      }
37  
38      @Override
39      protected void doResolve(String inetHost, Promise<InetAddress> promise) throws Exception {
40          try {
41              promise.setSuccess(SocketUtils.addressByName(inetHost));
42          } catch (UnknownHostException e) {
43              promise.setFailure(e);
44          }
45      }
46  
47      @Override
48      protected void doResolveAll(String inetHost, Promise<List<InetAddress>> promise) throws Exception {
49          try {
50              promise.setSuccess(Arrays.asList(SocketUtils.allAddressesByName(inetHost)));
51          } catch (UnknownHostException e) {
52              promise.setFailure(e);
53          }
54      }
55  }