/**
* Joins a multicast group. Its behavior may be affected by {@code setInterface} or {@code
* setNetworkInterface}.
*
* <p>If there is a security manager, this method first calls its {@code checkMulticast} method
* with the {@code mcastaddr} argument as its argument.
*
* @param mcastaddr is the multicast address to join
* @exception IOException if there is an error joining or when the address is not a multicast
* address.
* @exception SecurityException if a security manager exists and its {@code checkMulticast} method
* doesn't allow the join.
* @see SecurityManager#checkMulticast(InetAddress)
*/
public void joinGroup(InetAddress mcastaddr) throws IOException {
if (isClosed()) {
throw new SocketException("Socket is closed");
}
checkAddress(mcastaddr, "joinGroup");
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkMulticast(mcastaddr);
}
if (!mcastaddr.isMulticastAddress()) {
throw new SocketException("Not a multicast address");
}
/**
* required for some platforms where it's not possible to join a group without setting the
* interface first.
*/
NetworkInterface defaultInterface = NetworkInterface.getDefault();
if (!interfaceSet && defaultInterface != null) {
setNetworkInterface(defaultInterface);
}
getImpl().join(mcastaddr);
}
/** Publish a request message to the specified multicast group. */
protected void publishRequest(String message) throws IOException, SocketException {
groupAddr = InetAddress.getByName(request_group);
interfaceAddr = InetAddress.getByName(request_interface_address);
/* is it a multicast address? */
if (groupAddr.isMulticastAddress()) {
/* open the socket and join the multicast group */
udpSocket = new MulticastSocket();
udpSocket.setNetworkInterface(NetworkInterface.getByInetAddress(interfaceAddr));
udpSocket.setInterface(interfaceAddr);
udpSocket.joinGroup(groupAddr);
/* Send request packet */
DatagramPacket p =
new DatagramPacket(message.getBytes(), message.getBytes().length, groupAddr, 7777);
System.out.println("Sending request: " + new String(p.getData(), 0, p.getLength()));
udpSocket.send(p);
} else {
System.err.println("Invalid multicast address: " + groupAddr.toString());
}
}
private void createSocket() throws IOException {
if (this.getTheSocket() == null) {
MulticastSocket socket;
if (this.isAcknowledge()) {
if (logger.isDebugEnabled()) {
logger.debug("Listening for acks on port: " + this.getAckPort());
}
if (localAddress == null) {
socket = new MulticastSocket(this.getAckPort());
} else {
InetAddress whichNic = InetAddress.getByName(this.localAddress);
socket = new MulticastSocket(new InetSocketAddress(whichNic, this.getAckPort()));
}
if (this.getSoReceiveBufferSize() > 0) {
socket.setReceiveBufferSize(this.getSoReceiveBufferSize());
}
} else {
socket = new MulticastSocket();
}
if (this.timeToLive >= 0) {
socket.setTimeToLive(this.timeToLive);
}
setSocketAttributes(socket);
if (localAddress != null) {
InetAddress whichNic = InetAddress.getByName(this.localAddress);
NetworkInterface intfce = NetworkInterface.getByInetAddress(whichNic);
socket.setNetworkInterface(intfce);
}
this.setSocket(socket);
}
}
@Override
public void setNetworkInterface(NetworkInterface networkInterface) {
if (socket instanceof MulticastSocket) {
try {
((MulticastSocket) socket).setNetworkInterface(networkInterface);
} catch (SocketException e) {
throw new ChannelException(e);
}
} else {
throw new UnsupportedOperationException();
}
}
/**
* Creates an array of sockets with TTL and network interface set.
*
* @param mcastTTL multicast TTL.
* @return an array of multicast sockets to broadcast on.
* @throws IOException if I/O error occurred while creating a multicast socket.
* @noinspection SocketOpenedButNotSafelyClosed, ConstantConditions
*/
private static MulticastSocket[] createSockets(final int mcastTTL) throws IOException {
Exception lastException = null; // Records last error in case we could not create any sockets
final List<MulticastSocket> socketList = new ArrayList<MulticastSocket>(11);
final Enumeration<NetworkInterface> enumeration = NetworkInterface.getNetworkInterfaces();
while (enumeration.hasMoreElements()) {
try {
final NetworkInterface netIf = enumeration.nextElement();
final MulticastSocket socket = new MulticastSocket(); // NOPMD
socket.setTimeToLive(mcastTTL);
socket.setNetworkInterface(netIf);
socket.setSendBufferSize(SEND_BUFFER_SIZE);
socketList.add(socket);
} catch (final Exception e) {
lastException = e;
ExceptionUtils.ignoreException(e, "continue to connect to those we can");
}
}
if (socketList.isEmpty()) {
throw new IOException(
"Could not create at least one multicast socket. Last error: " + lastException);
}
return socketList.toArray(new MulticastSocket[socketList.size()]);
}
