1.1 --- a/org/sonews/daemon/ChannelReader.java Sun Aug 29 17:04:25 2010 +0200
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,202 +0,0 @@
1.4 -/*
1.5 - * SONEWS News Server
1.6 - * see AUTHORS for the list of contributors
1.7 - *
1.8 - * This program is free software: you can redistribute it and/or modify
1.9 - * it under the terms of the GNU General Public License as published by
1.10 - * the Free Software Foundation, either version 3 of the License, or
1.11 - * (at your option) any later version.
1.12 - *
1.13 - * This program is distributed in the hope that it will be useful,
1.14 - * but WITHOUT ANY WARRANTY; without even the implied warranty of
1.15 - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
1.16 - * GNU General Public License for more details.
1.17 - *
1.18 - * You should have received a copy of the GNU General Public License
1.19 - * along with this program. If not, see <http://www.gnu.org/licenses/>.
1.20 - */
1.21 -
1.22 -package org.sonews.daemon;
1.23 -
1.24 -import java.io.IOException;
1.25 -import java.nio.ByteBuffer;
1.26 -import java.nio.channels.CancelledKeyException;
1.27 -import java.nio.channels.SelectionKey;
1.28 -import java.nio.channels.Selector;
1.29 -import java.nio.channels.SocketChannel;
1.30 -import java.util.Iterator;
1.31 -import java.util.Set;
1.32 -import java.util.logging.Level;
1.33 -import org.sonews.util.Log;
1.34 -
1.35 -/**
1.36 - * A Thread task listening for OP_READ events from SocketChannels.
1.37 - * @author Christian Lins
1.38 - * @since sonews/0.5.0
1.39 - */
1.40 -class ChannelReader extends AbstractDaemon
1.41 -{
1.42 -
1.43 - private static ChannelReader instance = new ChannelReader();
1.44 -
1.45 - /**
1.46 - * @return Active ChannelReader instance.
1.47 - */
1.48 - public static ChannelReader getInstance()
1.49 - {
1.50 - return instance;
1.51 - }
1.52 -
1.53 - private Selector selector = null;
1.54 -
1.55 - protected ChannelReader()
1.56 - {
1.57 - }
1.58 -
1.59 - /**
1.60 - * Sets the selector which is used by this reader to determine the channel
1.61 - * to read from.
1.62 - * @param selector
1.63 - */
1.64 - public void setSelector(final Selector selector)
1.65 - {
1.66 - this.selector = selector;
1.67 - }
1.68 -
1.69 - /**
1.70 - * Run loop. Blocks until some data is available in a channel.
1.71 - */
1.72 - @Override
1.73 - public void run()
1.74 - {
1.75 - assert selector != null;
1.76 -
1.77 - while(isRunning())
1.78 - {
1.79 - try
1.80 - {
1.81 - // select() blocks until some SelectableChannels are ready for
1.82 - // processing. There is no need to lock the selector as we have only
1.83 - // one thread per selector.
1.84 - selector.select();
1.85 -
1.86 - // Get list of selection keys with pending events.
1.87 - // Note: the selected key set is not thread-safe
1.88 - SocketChannel channel = null;
1.89 - NNTPConnection conn = null;
1.90 - final Set<SelectionKey> selKeys = selector.selectedKeys();
1.91 - SelectionKey selKey = null;
1.92 -
1.93 - synchronized (selKeys)
1.94 - {
1.95 - Iterator it = selKeys.iterator();
1.96 -
1.97 - // Process the first pending event
1.98 - while (it.hasNext())
1.99 - {
1.100 - selKey = (SelectionKey) it.next();
1.101 - channel = (SocketChannel) selKey.channel();
1.102 - conn = Connections.getInstance().get(channel);
1.103 -
1.104 - // Because we cannot lock the selKey as that would cause a deadlock
1.105 - // we lock the connection. To preserve the order of the received
1.106 - // byte blocks a selection key for a connection that has pending
1.107 - // read events is skipped.
1.108 - if (conn == null || conn.tryReadLock())
1.109 - {
1.110 - // Remove from set to indicate that it's being processed
1.111 - it.remove();
1.112 - if (conn != null)
1.113 - {
1.114 - break; // End while loop
1.115 - }
1.116 - }
1.117 - else
1.118 - {
1.119 - selKey = null;
1.120 - channel = null;
1.121 - conn = null;
1.122 - }
1.123 - }
1.124 - }
1.125 -
1.126 - // Do not lock the selKeys while processing because this causes
1.127 - // a deadlock in sun.nio.ch.SelectorImpl.lockAndDoSelect()
1.128 - if (selKey != null && channel != null && conn != null)
1.129 - {
1.130 - processSelectionKey(conn, channel, selKey);
1.131 - conn.unlockReadLock();
1.132 - }
1.133 -
1.134 - }
1.135 - catch(CancelledKeyException ex)
1.136 - {
1.137 - Log.get().warning("ChannelReader.run(): " + ex);
1.138 - Log.get().log(Level.INFO, "", ex);
1.139 - }
1.140 - catch(Exception ex)
1.141 - {
1.142 - ex.printStackTrace();
1.143 - }
1.144 -
1.145 - // Eventually wait for a register operation
1.146 - synchronized (NNTPDaemon.RegisterGate)
1.147 - {
1.148 - // Do nothing; FindBugs may warn about an empty synchronized
1.149 - // statement, but we cannot use a wait()/notify() mechanism here.
1.150 - // If we used something like RegisterGate.wait() we block here
1.151 - // until the NNTPDaemon calls notify(). But the daemon only
1.152 - // calls notify() if itself is NOT blocked in the listening socket.
1.153 - }
1.154 - } // while(isRunning())
1.155 - }
1.156 -
1.157 - private void processSelectionKey(final NNTPConnection connection,
1.158 - final SocketChannel socketChannel, final SelectionKey selKey)
1.159 - throws InterruptedException, IOException
1.160 - {
1.161 - assert selKey != null;
1.162 - assert selKey.isReadable();
1.163 -
1.164 - // Some bytes are available for reading
1.165 - if(selKey.isValid())
1.166 - {
1.167 - // Lock the channel
1.168 - //synchronized(socketChannel)
1.169 - {
1.170 - // Read the data into the appropriate buffer
1.171 - ByteBuffer buf = connection.getInputBuffer();
1.172 - int read = -1;
1.173 - try
1.174 - {
1.175 - read = socketChannel.read(buf);
1.176 - }
1.177 - catch(IOException ex)
1.178 - {
1.179 - // The connection was probably closed by the remote host
1.180 - // in a non-clean fashion
1.181 - Log.get().info("ChannelReader.processSelectionKey(): " + ex);
1.182 - }
1.183 - catch(Exception ex)
1.184 - {
1.185 - Log.get().warning("ChannelReader.processSelectionKey(): " + ex);
1.186 - }
1.187 -
1.188 - if(read == -1) // End of stream
1.189 - {
1.190 - selKey.cancel();
1.191 - }
1.192 - else if(read > 0) // If some data was read
1.193 - {
1.194 - ConnectionWorker.addChannel(socketChannel);
1.195 - }
1.196 - }
1.197 - }
1.198 - else
1.199 - {
1.200 - // Should not happen
1.201 - Log.get().severe("Should not happen: " + selKey.toString());
1.202 - }
1.203 - }
1.204 -
1.205 -}