/*

 * 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.

 *

 */

import java.net.InetAddress;

import java.util.*;

import javax.naming.*;

import javax.naming.directory.*;

/*

 * Tests if a canonical name (CNAME) record exists for a

 * specified host - throws exception if DNS isn't configured

 * or there isn't a CNAME record.

 */

public class CanonicalName {

    public static void main(String args[]) throws Exception {

        final Hashtable<String,String> env = new Hashtable<String,String>();

        env.put("java.naming.factory.initial",

                "com.sun.jndi.dns.DnsContextFactory");

        DirContext ctx = new InitialDirContext(env);

        String ids[] = { "CNAME" };

        Attributes attrs = ctx.getAttributes(args[0], ids);

        NamingEnumeration ne = attrs.getAll();

        if (!ne.hasMoreElements()) {

            throw new Exception("no CNAME record");

        }

        // print out the CNAME records

        while (ne.hasMoreElements()) {

            Attribute attr = (Attribute)ne.next();

            for (NamingEnumeration e = attr.getAll(); e.hasMoreElements();) {

                System.out.println(args[0] + " -> " + e.next());

            }

        }

    }

}