/***************************************************************************
* (C) Copyright 2003-2010 - Marauroa *
***************************************************************************
***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
package marauroa.server.net.nio;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.channels.spi.SelectorProvider;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import marauroa.common.Log4J;
/**
* This class is the basic schema for a nio server. It works in a pattern of
* master/slave.
*
* @author miguel
*
*/
class NioServer extends Thread {
private static final int BACKLOG_WARNING_SIZE = 10;
/** the logger instance. */
private static final marauroa.common.Logger logger = Log4J.getLogger(NioServer.class);
/** The host:port combination to listen on */
private final InetAddress hostAddress;
private final int port;
/** While keepRunning is true, we keep receiving messages */
private boolean keepRunning;
/** isFinished is true when the thread has really exited. */
private boolean isFinished;
/** The channel on which we'll accept connections */
private ServerSocketChannel serverChannel;
/** The selector we'll be monitoring */
private final Selector selector;
/** The buffer into which we'll read data when it's available */
private final ByteBuffer readBuffer = ByteBuffer.allocate(8192);
/**
* This is the slave associated with this master. As it is a simple thread,
* we only need one slave.
*/
private final IWorker worker;
/** A list of PendingChange instances */
private final List<ChangeRequest> pendingChanges = new LinkedList<ChangeRequest>();
private final List<ChangeRequest> pendingClosed;
/** Maps a SocketChannel to a list of ByteBuffer instances */
private final Map<SocketChannel, List<ByteBuffer>> pendingData = new HashMap<SocketChannel, List<ByteBuffer>>();
public NioServer(InetAddress hostAddress, int port, IWorker worker) throws IOException {
super("NioServer");
keepRunning = true;
isFinished = false;
this.hostAddress = hostAddress;
this.port = port;
this.selector = this.initSelector();
this.worker = worker;
this.worker.setServer(this);
pendingClosed = new LinkedList<ChangeRequest>();
}
/**
* This method closes a channel. It also notify any listener about the
* event.
*
* @param channel
* the channel to close.
*/
public void close(SocketChannel channel) {
worker.onDisconnect(channel);
// We ask the server to close the channel
synchronized (this.pendingClosed) {
pendingClosed.add(new ChangeRequest(channel, ChangeRequest.CLOSE, 0));
}
// Wake up to make the closure effective.
selector.wakeup();
}
/**
* This method is used to send data on a socket.
*
* @param socket
* the socketchannel to use.
* @param data
* a byte array of data to send
*/
public void send(SocketChannel socket, byte[] data) {
synchronized (this.pendingChanges) {
// Indicate we want the interest ops set changed
this.pendingChanges.add(new ChangeRequest(socket, ChangeRequest.CHANGEOPS,
SelectionKey.OP_WRITE));
// And queue the data we want written
synchronized (this.pendingData) {
List<ByteBuffer> queue = this.pendingData.get(socket);
if (queue == null) {
queue = new ArrayList<ByteBuffer>();
this.pendingData.put(socket, queue);
}
queue.add(ByteBuffer.wrap(data));
if (queue.size() > BACKLOG_WARNING_SIZE) {
logger.debug(socket + ": " + queue.size());
}
}
}
// Finally, wake up our selecting thread so it can make the required
// changes
this.selector.wakeup();
}
/**
* Finish this thread in a correct way.
*/
public void finish() {
keepRunning = false;
selector.wakeup();
while (!(isFinished)) {
Thread.yield();
}
try {
selector.close();
} catch (IOException e) {
// We really don't care about the exception.
}
}
@Override
public void run() {
while (keepRunning) {
try {
// Process any pending changes
synchronized (this.pendingChanges) {
Iterator<?> changes = this.pendingChanges.iterator();
while (changes.hasNext()) {
ChangeRequest change = (ChangeRequest) changes.next();
if (change.socket.isConnected()) {
if (change.type == ChangeRequest.CHANGEOPS) {
SelectionKey key = change.socket.keyFor(this.selector);
if ((key != null) && key.isValid()) {
key.interestOps(change.ops);
}
}
}
}
this.pendingChanges.clear();
}
synchronized (this.pendingClosed) {
Iterator<?> it = pendingClosed.iterator();
while (it.hasNext()) {
ChangeRequest change = (ChangeRequest) it.next();
if (change.socket.isConnected()) {
if (change.type == ChangeRequest.CLOSE) {
try {
// Force data to be sent if there is data waiting.
if (pendingData.containsKey(change.socket)) {
SelectionKey key = change.socket.keyFor(selector);
if (key.isValid()) {
write(key);
}
}
// Close the socket
change.socket.close();
} catch (Exception e) {
logger.info("Exception happened when closing socket", e);
}
break;
}
} else {
logger.info("Closing a not connected socket");
}
}
pendingClosed.clear();
}
// Wait for an event one of the registered channels
this.selector.select();
// Iterate over the set of keys for which events are available
Iterator<?> selectedKeys = this.selector.selectedKeys().iterator();
while (selectedKeys.hasNext()) {
SelectionKey key = (SelectionKey) selectedKeys.next();
selectedKeys.remove();
if (!key.isValid()) {
continue;
}
// Check what event is available and deal with it
if (key.isAcceptable()) {
this.accept(key);
} else if (key.isReadable()) {
this.read(key);
} else if (key.isWritable()) {
this.write(key);
}
}
} catch (IOException e) {
logger.error("Error on NIOServer", e);
} catch (RuntimeException e) {
logger.error("Error on NIOServer", e);
}
}
isFinished = true;
}
private void accept(SelectionKey key) throws IOException {
// For an accept to be pending the channel must be a server socket
// channel.
ServerSocketChannel serverSocketChannel = (ServerSocketChannel) key.channel();
// Accept the connection and make it non-blocking
SocketChannel socketChannel = serverSocketChannel.accept();
socketChannel.configureBlocking(false);
// Register the new SocketChannel with our Selector, indicating
// we'd like to be notified when there's data waiting to be read
socketChannel.register(this.selector, SelectionKey.OP_READ);
worker.onConnect(socketChannel);
}
private void read(SelectionKey key) {
SocketChannel socketChannel = (SocketChannel) key.channel();
// Clear out our read buffer so it's ready for new data
this.readBuffer.clear();
// Attempt to read off the channel
int numRead;
try {
numRead = socketChannel.read(this.readBuffer);
} catch (IOException e) {
// The remote forcibly closed the connection, cancel
// the selection key and close the channel.
logger.debug("Remote closed connnection", e);
key.cancel();
close(socketChannel);
return;
}
if (numRead == -1) {
// Remote entity shut the socket down cleanly. Do the
// same from our end and cancel the channel.
logger.debug("Remote closed connnection cleanly");
close((SocketChannel) key.channel());
key.cancel();
return;
}
// Hand the data off to our worker thread
this.worker.onData(this, socketChannel, this.readBuffer.array(), numRead);
}
private void write(SelectionKey key) {
SocketChannel socketChannel = (SocketChannel) key.channel();
synchronized (this.pendingData) {
List<ByteBuffer> queue = this.pendingData.get(socketChannel);
try {
// Write until there's not more data ...
while (!queue.isEmpty()) {
ByteBuffer buf = queue.get(0);
socketChannel.write(buf);
if (buf.remaining() > 0) {
// ... or the socket's buffer fills up
break;
}
queue.remove(0);
}
if (queue.isEmpty()) {
// We wrote away all data, so we're no longer interested
// in writing on this socket. Switch back to waiting for
// data.
key.interestOps(SelectionKey.OP_READ);
}
} catch (IOException e) {
// The remote forcibly closed the connection, cancel
// the selection key and close the channel.
logger.debug("Remote closed connnection", e);
queue.clear();
key.cancel();
close(socketChannel);
return;
}
}
}
private Selector initSelector() throws IOException {
// Create a new selector
Selector socketSelector = SelectorProvider.provider().openSelector();
// Create a new non-blocking server socket channel
this.serverChannel = ServerSocketChannel.open();
serverChannel.configureBlocking(false);
// Bind the server socket to the specified address and port
InetSocketAddress isa = new InetSocketAddress(this.hostAddress, this.port);
serverChannel.socket().bind(isa);
serverChannel.socket().setPerformancePreferences(0, 2, 1);
// Register the server socket channel, indicating an interest in
// accepting new connections
serverChannel.register(socketSelector, SelectionKey.OP_ACCEPT);
return socketSelector;
}
}
