/*

 * Copyright 2007-2008 Sun Microsystems, Inc.  All Rights Reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 *   - Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer.

 *

 *   - Redistributions in binary form must reproduce the above copyright

 *     notice, this list of conditions and the following disclaimer in the

 *     documentation and/or other materials provided with the distribution.

 *

 *   - Neither the name of Sun Microsystems nor the names of its

 *     contributors may be used to endorse or promote products derived

 *     from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

import java.net.InetAddress;

import java.net.NetworkInterface;

import java.net.UnknownHostException;

import java.net.SocketException;

/**

 * Parses and represents a multicast address.

 */

class MulticastAddress {

    private final InetAddress group;

    private final int port;

    private final NetworkInterface interf;

    private MulticastAddress(InetAddress group, int port, NetworkInterface interf) {

        this.group = group;

        this.port = port;

        this.interf = interf;

    }

    InetAddress group() {

        return group;

    }

    int port() {

        return port;

    }

    /**

     * @return  The network interface, may be {@code null}

     */

    NetworkInterface interf() {

        return interf;

    }

    /**

     * Parses a string of the form "group:port[@interface]", returning

     * a MulticastAddress representing the address

     */

    static MulticastAddress parse(String s) {

        String[] components = s.split("@");

        if (components.length > 2)

            throw new IllegalArgumentException("At most one '@' expected");

        // get group and port

        String target = components[0];

        int len = components[0].length();

        int colon = components[0].lastIndexOf(':');

        if ((colon < 1) || (colon > (len-2)))

            throw new IllegalArgumentException("group:port expected");

        String groupString = target.substring(0, colon);

        int port = -1;

        try {

            port = Integer.parseInt(target.substring(colon+1, len));

        } catch (NumberFormatException x) {

             throw new IllegalArgumentException(x);

        }

        // handle IPv6 literal address

        if (groupString.charAt(0) == '[') {

            len = groupString.length();

            if (groupString.charAt(len-1) != ']')

                throw new IllegalArgumentException("missing ']'");

            groupString = groupString.substring(1,len-1);

            if (groupString.length() == 0)

                throw new IllegalArgumentException("missing IPv6 address");

        }

        // get group address

        InetAddress group = null;

        try {

            group = InetAddress.getByName(groupString);

        } catch (UnknownHostException x) {

            throw new IllegalArgumentException(x);

        }

        if (!group.isMulticastAddress()) {

            throw new IllegalArgumentException("'" + group.getHostAddress() +

                "' is not multicast address");

        }

        // optional interface

        NetworkInterface interf = null;

        if (components.length == 2) {

            try {

                interf = NetworkInterface.getByName(components[1]);

            } catch (SocketException x) {

                throw new IllegalArgumentException(x);

            }

            if (interf == null) {

                throw new IllegalArgumentException("'" + components[1] +

                   "' is not valid interface");

            }

        }

        return new MulticastAddress(group, port, interf);

    }

}