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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    *   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  
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  import io.netty.util.internal.UnstableApi;
23  
24  import java.net.InetAddress;
25  import java.net.UnknownHostException;
26  import java.util.Arrays;
27  import java.util.List;
28  
29  /**
30   * A {@link InetNameResolver} that resolves using JDK's built-in domain name lookup mechanism.
31   * Note that this resolver performs a blocking name lookup from the caller thread.
32   */
33  @UnstableApi
34  public class DefaultNameResolver extends InetNameResolver {
35  
36      public DefaultNameResolver(EventExecutor executor) {
37          super(executor);
38      }
39  
40      @Override
41      protected void doResolve(String inetHost, Promise<InetAddress> promise) throws Exception {
42          try {
43              promise.setSuccess(SocketUtils.addressByName(inetHost));
44          } catch (UnknownHostException e) {
45              promise.setFailure(e);
46          }
47      }
48  
49      @Override
50      protected void doResolveAll(String inetHost, Promise<List<InetAddress>> promise) throws Exception {
51          try {
52              promise.setSuccess(Arrays.asList(SocketUtils.allAddressesByName(inetHost)));
53          } catch (UnknownHostException e) {
54              promise.setFailure(e);
55          }
56      }
57  }