package org.menacheri.jetclient;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import org.jboss.netty.bootstrap.ConnectionlessBootstrap;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelFactory;
import org.jboss.netty.channel.ChannelFuture;
import org.jboss.netty.channel.ChannelFutureListener;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelPipelineFactory;
import org.jboss.netty.channel.socket.DatagramChannel;
import org.jboss.netty.channel.socket.DatagramChannelFactory;
import org.jboss.netty.channel.socket.nio.NioDatagramChannelFactory;
import org.menacheri.jetclient.app.Session;
import org.menacheri.jetclient.event.Events;
import org.menacheri.jetclient.event.Event;
import org.menacheri.jetclient.handlers.netty.UDPUpstreamHandler;
/**
* This client class is used for UDP communication with a remote jetserver. Same
* client instance can be used to create multiple UDP "connections" to same
* jetserver. For connecting with multiple jetserver's use multiple instances of
* this class.
*
* @author Abraham Menacherry
*
*/
public class NettyUDPClient
{
/**
* The remote server address to which this client should connect.
*/
private final InetSocketAddress serverAddress;
/**
* The worker executor which will provide threads to Netty
* {@link ChannelFactory} for decoding encoding done on the
* {@link ChannelPipeline}.
*/
private final ExecutorService worker;
private final ConnectionlessBootstrap udpBootstrap;
/**
* The instance of {@link NioDatagramChannelFactory} created by constructor,
* or the one passed in to constructor.
*/
private final DatagramChannelFactory channelFactory;
/**
* For UDP there can only be one pipelineFactory per
* {@link ConnectionlessBootstrap}. This factory is hence part of the client
* class.
*/
private final ChannelPipelineFactory pipelineFactory;
/**
* This map is used to store the local address to which a session has bound
* itself using the {@link DatagramChannel#bind(java.net.SocketAddress)}
* method. When an incoming UDP packet is recieved the
* {@link UDPUpstreamHandler} will resolve which session to pass the event,
* using this map.
*/
public static final Map<InetSocketAddress, Session> CLIENTS = new HashMap<InetSocketAddress, Session>();
/**
* Creates an instance of a Netty UDP client which can then be used to
* connect to a remote jet-server. This constructor delegates to
* {@link #NettyUDPClient(InetSocketAddress, ChannelPipelineFactory)}
* constructor after creating a {@link InetSocketAddress} instance based on
* the host and port number passed in.
*
* @param jetserverHost
* The host name of the remote server on which jetserver is
* running.
* @param port
* The port to connect to, on the remote server.
* @param pipelineFactory
* The pipeline factory to be used while creating a Netty
* {@link Channel}
* @throws UnknownHostException
* @throws Exception
*/
public NettyUDPClient(String jetserverHost, int port,
final ChannelPipelineFactory pipelineFactory)
throws UnknownHostException, Exception
{
this(new InetSocketAddress(jetserverHost, port), pipelineFactory);
}
public NettyUDPClient(final InetSocketAddress serverAddress,
final ChannelPipelineFactory pipelineFactory)
throws UnknownHostException, Exception
{
this(serverAddress, pipelineFactory, null, Executors
.newCachedThreadPool());
}
/**
* Creates a new instance of the {@link NettyUDPClient}.
*
* @param serverAddress
* The remote servers address. This address will be used when any
* of the default write/connect methods are used.
* @param pipelineFactory
* The Netty factory used for creating a pipeline. For UDP, this
* pipeline factory should not have any stateful i.e non
* share-able handlers in it. Since Netty only has one channel
* for <b>ALL</b> UPD traffic.
* @param channelFactory
* <b>Can be provided as null</b>. If so, it will by default use
* {@link NioDatagramChannelFactory}. If not null, then the
* provided factory is set.
* @param worker
* The executor used for creating worker threads. Can be null if
* channelFactory parameter is <b>Not</b> null.
* @throws UnknownHostException
*/
public NettyUDPClient(final InetSocketAddress serverAddress,
final ChannelPipelineFactory pipelineFactory,
final DatagramChannelFactory channelFactory,
final ExecutorService worker) throws UnknownHostException,
Exception
{
this.worker = worker;
this.serverAddress = serverAddress;
if (channelFactory == null)
{
this.channelFactory = new NioDatagramChannelFactory(worker);
}
else
{
this.channelFactory = channelFactory;
}
this.udpBootstrap = new ConnectionlessBootstrap(this.channelFactory);
udpBootstrap.setOption("broadcast", "true");
this.pipelineFactory = pipelineFactory;
// The pipeline factory should not be set on the udpBootstrap since it
// invalidates the getPipeline.
udpBootstrap.setPipeline(pipelineFactory.getPipeline());
Runtime.getRuntime().addShutdownHook(new Thread()
{
public void run()
{
udpBootstrap.releaseExternalResources();
}
});
}
/**
* Creates a new datagram channel instance using the {@link #udpBootstrap}
* by binding to local host. This method delegates to
* {@link #createDatagramChannel(String)} internally, by passing the
* localhost's host name to it.
*
* @return The newly created instance of the datagram channel.
* @throws UnknownHostException
*/
public DatagramChannel createDatagramChannel() throws UnknownHostException
{
return createDatagramChannel(InetAddress.getLocalHost()
.getHostAddress());
}
/**
* Creates a new datagram channel instance using the {@link #udpBootstrap}
* by binding to local host.
*
* @param localhostName
* The host machine (for e.g. 'localhost') to which it needs to
* bind to. This is <b>Not</b> the remote jet-server hostname.
* @return The newly created instance of the datagram channel.
* @throws UnknownHostException
*/
public DatagramChannel createDatagramChannel(String localhostName)
throws UnknownHostException
{
DatagramChannel datagramChannel = (DatagramChannel) udpBootstrap
.bind(new InetSocketAddress(localhostName, 0));
return datagramChannel;
}
/**
* This method will connect the datagram channel with the server and send
* the {@link Events#CONNECT} message to server. This method will use
* {@link #serverAddress} by default when sending the
* {@link Events#CONNECT} message. <b>Note</b> Even if this connect
* message does not reach server, the first UDP message that the server
* receives from this particular DatagramChannels local address will be
* converted by server and used as {@link Events#CONNECT}.
*
* @param session
* The session for which the datagram channel is being created.
* @param datagramChannel
* The channel on which the message is to be sent to remote
* server.
* @return Returns a ChannelFuture which can be used to check the success of
* this operation. <b>NOTE</b> Success in case of UDP means message
* is sent to server. It does not mean that the server has received
* it.
* @throws UnknownHostException
*/
public ChannelFuture connect(Session session,
DatagramChannel datagramChannel) throws UnknownHostException,
InterruptedException
{
return connect(session, datagramChannel, this.serverAddress, 5,
TimeUnit.SECONDS);
}
/**
* This method will connect the datagram channel with the server and send
* the {@link Events#CONNECT} message to server.
*
* @param session
* The session for which the datagram channel is being created.
* @param datagramChannel
* The channel on which the message is to be sent to remote
* server.
* @param serverAddress
* The remote address of the server to which to send this
* message.
* @param timeout
* Amount of time to wait for the connection to happen.
* <b>NOTE</b> Since this is UDP there is actually no "real"
* connection.
* @return Returns a ChannelFuture which can be used to check the success of
* this operation. <b>NOTE</b> Success in case of UDP means message
* is sent to server. It does not mean that the server has received
* it.
* @throws UnknownHostException
*/
public ChannelFuture connect(Session session,
DatagramChannel datagramChannel, InetSocketAddress serverAddress,
int timeout, TimeUnit unit) throws UnknownHostException,
InterruptedException
{
if (null == datagramChannel)
{
throw new NullPointerException(
"DatagramChannel passed to connect method cannot be null");
}
if (!datagramChannel.isBound())
{
throw new IllegalStateException("DatagramChannel: "
+ datagramChannel
+ " Passed to connect method is not bound");
}
Event event = Events.event(null, Events.CONNECT);
ChannelFuture future = datagramChannel.write(event, serverAddress);
future.addListener(new ChannelFutureListener()
{
@Override
public void operationComplete(ChannelFuture future)
throws Exception
{
if (!future.isSuccess())
{
throw new RuntimeException(future.getCause());
}
}
});
CLIENTS.put(datagramChannel.getLocalAddress(), session);
return future;
}
/**
* Utility method used to send a message to the server. Users can also use
* datagramChannel.write(message, serverAddress) directly. This method
* delegates to {@link #write(DatagramChannel, Object, InetSocketAddress)}
* by passing in the InetSocketAddress stored in the class variable
* {@link #serverAddress}
*
* @param datagramChannel
* The channel on which the message is to be sent to remote
* server.
* @param message
* The message to be sent. <b>NOTE</b> The message should be a
* valid and encode-able by the encoders in the ChannelPipeline
* of this server.
* @return Returns a ChannelFuture which can be used to check the success of
* this operation. <b>NOTE</b> Success in case of UDP means message
* is sent to server. It does not mean that the server has received
* it.
*/
public ChannelFuture write(DatagramChannel datagramChannel, Object message)
{
return write(datagramChannel, message, serverAddress);
}
/**
* Utility method used to send a message to the server. Users can also use
* datagramChannel.write(message, serverAddress) directly.
*
* @param datagramChannel
* The channel on which the message is to be sent to remote
* server.
* @param message
* The message to be sent. <b>NOTE</b> The message should be a
* valid and encode-able by the encoders in the ChannelPipeline
* of this server.
* @return Returns a ChannelFuture which can be used to check the success of
* this operation. <b>NOTE</b> Success in case of UDP means message
* is sent to server. It does not mean that the server has received
* it.
*/
public static ChannelFuture write(DatagramChannel datagramChannel, Object message,
InetSocketAddress serverAddress)
{
return datagramChannel.write(message, serverAddress);
}
public InetSocketAddress getServerAddress()
{
return serverAddress;
}
public ExecutorService getWorker()
{
return worker;
}
public ConnectionlessBootstrap getUdpBootstrap()
{
return udpBootstrap;
}
public DatagramChannelFactory getChannelFactory()
{
return channelFactory;
}
public ChannelPipelineFactory getPipelineFactory()
{
return pipelineFactory;
}
}