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.impl.conn;
28
29 import java.net.InetAddress;
30 import java.net.UnknownHostException;
31 import java.util.Arrays;
32 import java.util.Map;
33 import java.util.concurrent.ConcurrentHashMap;
34
35 import org.apache.commons.logging.Log;
36 import org.apache.commons.logging.LogFactory;
37 import org.apache.http.conn.DnsResolver;
38 import org.apache.http.util.Args;
39
40 /**
41 * In-memory {@link DnsResolver} implementation.
42 *
43 * @since 4.2
44 */
45 public class InMemoryDnsResolver implements DnsResolver {
46
47 /** Logger associated to this class. */
48 private final Log log = LogFactory.getLog(InMemoryDnsResolver.class);
49
50 /**
51 * In-memory collection that will hold the associations between a host name
52 * and an array of InetAddress instances.
53 */
54 private final Map<String, InetAddress[]> dnsMap;
55
56 /**
57 * Builds a DNS resolver that will resolve the host names against a
58 * collection held in-memory.
59 */
60 public InMemoryDnsResolver() {
61 dnsMap = new ConcurrentHashMap<String, InetAddress[]>();
62 }
63
64 /**
65 * Associates the given array of IP addresses to the given host in this DNS overrider.
66 * The IP addresses are assumed to be already resolved.
67 *
68 * @param host
69 * The host name to be associated with the given IP.
70 * @param ips
71 * array of IP addresses to be resolved by this DNS overrider to the given
72 * host name.
73 */
74 public void add(final String host, final InetAddress... ips) {
75 Args.notNull(host, "Host name");
76 Args.notNull(ips, "Array of IP addresses");
77 dnsMap.put(host, ips);
78 }
79
80 /**
81 * {@inheritDoc}
82 */
83 @Override
84 public InetAddress[] resolve(final String host) throws UnknownHostException {
85 final InetAddress[] resolvedAddresses = dnsMap.get(host);
86 if (log.isInfoEnabled()) {
87 log.info("Resolving " + host + " to " + Arrays.deepToString(resolvedAddresses));
88 }
89 if(resolvedAddresses == null){
90 throw new UnknownHostException(host + " cannot be resolved");
91 }
92 return resolvedAddresses;
93 }
94
95 }