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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  package org.apache.http.conn;
28  
29  import java.net.InetAddress;
30  import java.net.UnknownHostException;
31  
32  /**
33   * Users may implement this interface to override the normal DNS lookup offered
34   * by the OS.
35   *
36   * @since 4.2
37   */
38  public interface DnsResolver {
39  
40      /**
41       * Returns the IP address for the specified host name, or null if the given
42       * host is not recognized or the associated IP address cannot be used to
43       * build an InetAddress instance.
44       *
45       * @see InetAddress
46       *
47       * @param host
48       *            The host name to be resolved by this resolver.
49       * @return The IP address associated to the given host name, or null if the
50       *         host name is not known by the implementation class.
51       */
52      InetAddress[] resolve(String host) throws UnknownHostException;
53  
54  }