1 /*

     2  * Copyright (c) 2002, 2011, 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 }