/*
 * Copyright (c) 2013, 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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
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package sun.management.jdp;

import java.io.IOException;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.NetworkInterface;
import java.net.ProtocolFamily;
import java.net.StandardProtocolFamily;
import java.net.StandardSocketOptions;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.nio.channels.UnsupportedAddressTypeException;
import java.util.Enumeration;

JdpBroadcaster is responsible for sending pre-built JDP packet across a Net
 Multicast group address, port number and ttl have to be chosen on upper
level and passed to broadcaster constructor. Also it's possible to specify
source address to broadcast from. 
JdpBradcaster doesn't perform any validation on a supplied port and ttl because the allowed values depend on an operating system setup
/**
 * JdpBroadcaster is responsible for sending pre-built JDP packet across a Net
 *
 * <p> Multicast group address, port number and ttl have to be chosen on upper
 * level and passed to broadcaster constructor. Also it's possible to specify
 * source address to broadcast from. </p>
 *
 * <p>JdpBradcaster doesn't perform any validation on a supplied {@code port} and {@code ttl} because
 * the allowed values depend on an operating system setup</p>
 *
 */
public final class JdpBroadcaster {

    private final InetAddress addr;
    private final int port;
    private final DatagramChannel channel;

    
Create a new broadcaster
Params:
address – - multicast group address
srcAddress – - address of interface we should use to broadcast.
port – - udp port to use
ttl – - packet ttl
Throws:
IOException – /**
     * Create a new broadcaster
     *
     * @param address - multicast group address
     * @param srcAddress - address of interface we should use to broadcast.
     * @param port - udp port to use
     * @param ttl - packet ttl
     * @throws IOException
     */
    public JdpBroadcaster(InetAddress address, InetAddress srcAddress, int port, int ttl)
            throws IOException, JdpException {
        this.addr = address;
        this.port = port;

        ProtocolFamily family = (address instanceof Inet6Address)
                ? StandardProtocolFamily.INET6 : StandardProtocolFamily.INET;

        channel = DatagramChannel.open(family);
        channel.setOption(StandardSocketOptions.SO_REUSEADDR, true);
        channel.setOption(StandardSocketOptions.IP_MULTICAST_TTL, ttl);

        // with srcAddress equal to null, this constructor do exactly the same as
        // if srcAddress is not passed
        if (srcAddress != null) {
            // User requests particular interface to bind to
            NetworkInterface interf = NetworkInterface.getByInetAddress(srcAddress);

            if (interf == null) {
                throw new JdpException("Unable to get network interface for " + srcAddress.toString());
            }

            if (!interf.isUp()) {
                throw new JdpException(interf.getName() + " is not up.");
            }

            if (!interf.supportsMulticast()) {
                throw new JdpException(interf.getName() + " does not support multicast.");
            }

            try {
                channel.bind(new InetSocketAddress(srcAddress, 0));
            } catch (UnsupportedAddressTypeException ex) {
                throw new JdpException("Unable to bind to source address");
            }
            channel.setOption(StandardSocketOptions.IP_MULTICAST_IF, interf);
        }
    }

    
Create a new broadcaster
Params:
address – - multicast group address
port – - udp port to use
ttl – - packet ttl
Throws:
IOException – /**
     * Create a new broadcaster
     *
     * @param address - multicast group address
     * @param port - udp port to use
     * @param ttl - packet ttl
     * @throws IOException
     */
    public JdpBroadcaster(InetAddress address, int port, int ttl)
            throws IOException, JdpException {
        this(address, null, port, ttl);
    }

    
Broadcast pre-built packet
Params:
packet – - instance of JdpPacket
Throws:
IOException – /**
     * Broadcast pre-built packet
     *
     * @param packet - instance of JdpPacket
     * @throws IOException
     */
    public void sendPacket(JdpPacket packet)
            throws IOException {
        byte[] data = packet.getPacketData();
        // Unlike allocate/put wrap don't need a flip afterward
        ByteBuffer b = ByteBuffer.wrap(data);
        channel.send(b, new InetSocketAddress(addr, port));
    }

    
Shutdown broadcaster and close underlying socket channel
Throws:
IOException – /**
     * Shutdown broadcaster and close underlying socket channel
     *
     * @throws IOException
     */
    public void shutdown() throws IOException {
        channel.close();
    }
}