1 /*
   2  * Copyright (c) 2002, 2006, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 /*
  25  * A simple name service based on an in-memory HashMap.
  26  */
  27 import java.net.UnknownHostException;
  28 import java.net.InetAddress;
  29 import sun.net.spi.nameservice.*;
  30 import java.util.*;
  31 
  32 public final class SimpleNameService implements NameService {
  33 
  34     private static LinkedHashMap hosts = new LinkedHashMap();
  35 
  36     private static String addrToString(byte addr[]) {
  37         return Byte.toString(addr[0]) + "." +
  38                Byte.toString(addr[1]) + "." +
  39                Byte.toString(addr[2]) + "." +
  40                Byte.toString(addr[3]);
  41     }
  42 
  43     // ------------
  44 
  45     public static void put(String host, String addr) {
  46         hosts.put(host, addr);
  47     }
  48 
  49     public static void put(String host, byte addr[]) {
  50         hosts.put(host, addrToString(addr));
  51     }
  52 
  53     public static void remove(String host) {
  54         hosts.remove(host);
  55     }
  56 
  57     public static int entries () {
  58         return hosts.size();
  59     }
  60 
  61     public static int lookupCalls() {
  62         return lookupCalls;
  63     }
  64 
  65     static int lookupCalls = 0;
  66 
  67     // ------------
  68 
  69     public SimpleNameService() throws Exception {
  70     }
  71 
  72     public InetAddress[] lookupAllHostAddr(String host) throws UnknownHostException {
  73 
  74         lookupCalls ++;
  75 
  76         String value = (String)hosts.get(host);
  77         if (value == null) {
  78             throw new UnknownHostException(host);
  79         }
  80         StringTokenizer st = new StringTokenizer(value, ".");
  81         byte addr[] = new byte[4];
  82         for (int i=0; i<4; i++) {
  83             addr[i] = (byte)Integer.parseInt(st.nextToken());
  84         }
  85         InetAddress[] res = new InetAddress[1];
  86         res[0] = InetAddress.getByAddress(host, addr);
  87         return res;
  88     }
  89 
  90     public String getHostByAddr(byte[] addr) throws UnknownHostException {
  91         String addrString = addrToString(addr);
  92         Iterator i = hosts.keySet().iterator();
  93         while (i.hasNext()) {
  94             String host = (String)i.next();
  95             String value = (String)hosts.get(host);
  96             if (value.equals(addrString)) {
  97                 return host;
  98             }
  99         }
 100         throw new UnknownHostException();
 101     }
 102 }