/*

 * Copyright (c) 2002, 2011, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 * A simple name service based on an in-memory HashMap.

 */

import java.net.UnknownHostException;

import java.net.InetAddress;

import sun.net.spi.nameservice.*;

import java.util.*;

public final class SimpleNameService implements NameService {

    private static LinkedHashMap hosts = new LinkedHashMap();

    private static String addrToString(byte addr[]) {

        return Byte.toString(addr[0]) + "." +

               Byte.toString(addr[1]) + "." +

               Byte.toString(addr[2]) + "." +

               Byte.toString(addr[3]);

    }

    // ------------

    public static void put(String host, String addr) {

        hosts.put(host, addr);

    }

    public static void put(String host, byte addr[]) {

        hosts.put(host, addrToString(addr));

    }

    public static void remove(String host) {

        hosts.remove(host);

    }

    public static int entries () {

        return hosts.size();

    }

    public static int lookupCalls() {

        return lookupCalls;

    }

    static int lookupCalls = 0;

    // ------------

    public SimpleNameService() throws Exception {

    }

    public InetAddress[] lookupAllHostAddr(String host) throws UnknownHostException {

        lookupCalls ++;

        String value = (String)hosts.get(host);

        if (value == null) {

            throw new UnknownHostException(host);

        }

        StringTokenizer st = new StringTokenizer(value, ".");

        byte addr[] = new byte[4];

        for (int i=0; i<4; i++) {

            addr[i] = (byte)Integer.parseInt(st.nextToken());

        }

        InetAddress[] res = new InetAddress[1];

        res[0] = InetAddress.getByAddress(host, addr);

        return res;

    }

    public String getHostByAddr(byte[] addr) throws UnknownHostException {

        String addrString = addrToString(addr);

        Iterator i = hosts.keySet().iterator();

        while (i.hasNext()) {

            String host = (String)i.next();

            String value = (String)hosts.get(host);

            if (value.equals(addrString)) {

                return host;

            }

        }

        throw new UnknownHostException();

    }

}