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1   /*
2    * Copyright 2014 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.concurrent.EventExecutor;
20  import io.netty.util.concurrent.Promise;
21  
22  import java.net.InetAddress;
23  import java.net.InetSocketAddress;
24  import java.net.UnknownHostException;
25  
26  /**
27   * A {@link NameResolver} that resolves an {@link InetSocketAddress} using JDK's built-in domain name lookup mechanism.
28   * Note that this resolver performs a blocking name lookup from the caller thread.
29   */
30  public class DefaultNameResolver extends SimpleNameResolver<InetSocketAddress> {
31  
32      public DefaultNameResolver(EventExecutor executor) {
33          super(executor);
34      }
35  
36      @Override
37      protected boolean doIsResolved(InetSocketAddress address) {
38          return !address.isUnresolved();
39      }
40  
41      @Override
42      protected void doResolve(InetSocketAddress unresolvedAddress, Promise<InetSocketAddress> promise) throws Exception {
43          try {
44              promise.setSuccess(
45                      new InetSocketAddress(
46                              InetAddress.getByName(unresolvedAddress.getHostString()),
47                              unresolvedAddress.getPort()));
48          } catch (UnknownHostException e) {
49              promise.setFailure(e);
50          }
51      }
52  }