1.1 --- a/src/org/sonews/daemon/ChannelReader.java Sun Aug 29 17:28:58 2010 +0200
1.2 +++ b/src/org/sonews/daemon/ChannelReader.java Sun Aug 29 18:17:37 2010 +0200
1.3 @@ -37,166 +37,141 @@
1.4 class ChannelReader extends AbstractDaemon
1.5 {
1.6
1.7 - private static ChannelReader instance = new ChannelReader();
1.8 + private static ChannelReader instance = new ChannelReader();
1.9
1.10 - /**
1.11 - * @return Active ChannelReader instance.
1.12 - */
1.13 - public static ChannelReader getInstance()
1.14 - {
1.15 - return instance;
1.16 - }
1.17 -
1.18 - private Selector selector = null;
1.19 -
1.20 - protected ChannelReader()
1.21 - {
1.22 - }
1.23 -
1.24 - /**
1.25 - * Sets the selector which is used by this reader to determine the channel
1.26 - * to read from.
1.27 - * @param selector
1.28 - */
1.29 - public void setSelector(final Selector selector)
1.30 - {
1.31 - this.selector = selector;
1.32 - }
1.33 -
1.34 - /**
1.35 - * Run loop. Blocks until some data is available in a channel.
1.36 - */
1.37 - @Override
1.38 - public void run()
1.39 - {
1.40 - assert selector != null;
1.41 + /**
1.42 + * @return Active ChannelReader instance.
1.43 + */
1.44 + public static ChannelReader getInstance()
1.45 + {
1.46 + return instance;
1.47 + }
1.48 + private Selector selector = null;
1.49
1.50 - while(isRunning())
1.51 - {
1.52 - try
1.53 - {
1.54 - // select() blocks until some SelectableChannels are ready for
1.55 - // processing. There is no need to lock the selector as we have only
1.56 - // one thread per selector.
1.57 - selector.select();
1.58 + protected ChannelReader()
1.59 + {
1.60 + }
1.61
1.62 - // Get list of selection keys with pending events.
1.63 - // Note: the selected key set is not thread-safe
1.64 - SocketChannel channel = null;
1.65 - NNTPConnection conn = null;
1.66 - final Set<SelectionKey> selKeys = selector.selectedKeys();
1.67 - SelectionKey selKey = null;
1.68 + /**
1.69 + * Sets the selector which is used by this reader to determine the channel
1.70 + * to read from.
1.71 + * @param selector
1.72 + */
1.73 + public void setSelector(final Selector selector)
1.74 + {
1.75 + this.selector = selector;
1.76 + }
1.77
1.78 - synchronized (selKeys)
1.79 - {
1.80 - Iterator it = selKeys.iterator();
1.81 + /**
1.82 + * Run loop. Blocks until some data is available in a channel.
1.83 + */
1.84 + @Override
1.85 + public void run()
1.86 + {
1.87 + assert selector != null;
1.88
1.89 - // Process the first pending event
1.90 - while (it.hasNext())
1.91 - {
1.92 - selKey = (SelectionKey) it.next();
1.93 - channel = (SocketChannel) selKey.channel();
1.94 - conn = Connections.getInstance().get(channel);
1.95 + while (isRunning()) {
1.96 + try {
1.97 + // select() blocks until some SelectableChannels are ready for
1.98 + // processing. There is no need to lock the selector as we have only
1.99 + // one thread per selector.
1.100 + selector.select();
1.101
1.102 - // Because we cannot lock the selKey as that would cause a deadlock
1.103 - // we lock the connection. To preserve the order of the received
1.104 - // byte blocks a selection key for a connection that has pending
1.105 - // read events is skipped.
1.106 - if (conn == null || conn.tryReadLock())
1.107 - {
1.108 - // Remove from set to indicate that it's being processed
1.109 - it.remove();
1.110 - if (conn != null)
1.111 - {
1.112 - break; // End while loop
1.113 - }
1.114 - }
1.115 - else
1.116 - {
1.117 - selKey = null;
1.118 - channel = null;
1.119 - conn = null;
1.120 - }
1.121 - }
1.122 - }
1.123 + // Get list of selection keys with pending events.
1.124 + // Note: the selected key set is not thread-safe
1.125 + SocketChannel channel = null;
1.126 + NNTPConnection conn = null;
1.127 + final Set<SelectionKey> selKeys = selector.selectedKeys();
1.128 + SelectionKey selKey = null;
1.129
1.130 - // Do not lock the selKeys while processing because this causes
1.131 - // a deadlock in sun.nio.ch.SelectorImpl.lockAndDoSelect()
1.132 - if (selKey != null && channel != null && conn != null)
1.133 - {
1.134 - processSelectionKey(conn, channel, selKey);
1.135 - conn.unlockReadLock();
1.136 - }
1.137 + synchronized (selKeys) {
1.138 + Iterator it = selKeys.iterator();
1.139
1.140 - }
1.141 - catch(CancelledKeyException ex)
1.142 - {
1.143 - Log.get().warning("ChannelReader.run(): " + ex);
1.144 - Log.get().log(Level.INFO, "", ex);
1.145 - }
1.146 - catch(Exception ex)
1.147 - {
1.148 - ex.printStackTrace();
1.149 - }
1.150 -
1.151 - // Eventually wait for a register operation
1.152 - synchronized (NNTPDaemon.RegisterGate)
1.153 - {
1.154 - // Do nothing; FindBugs may warn about an empty synchronized
1.155 - // statement, but we cannot use a wait()/notify() mechanism here.
1.156 - // If we used something like RegisterGate.wait() we block here
1.157 - // until the NNTPDaemon calls notify(). But the daemon only
1.158 - // calls notify() if itself is NOT blocked in the listening socket.
1.159 - }
1.160 - } // while(isRunning())
1.161 - }
1.162 -
1.163 - private void processSelectionKey(final NNTPConnection connection,
1.164 - final SocketChannel socketChannel, final SelectionKey selKey)
1.165 - throws InterruptedException, IOException
1.166 - {
1.167 - assert selKey != null;
1.168 - assert selKey.isReadable();
1.169 -
1.170 - // Some bytes are available for reading
1.171 - if(selKey.isValid())
1.172 - {
1.173 - // Lock the channel
1.174 - //synchronized(socketChannel)
1.175 - {
1.176 - // Read the data into the appropriate buffer
1.177 - ByteBuffer buf = connection.getInputBuffer();
1.178 - int read = -1;
1.179 - try
1.180 - {
1.181 - read = socketChannel.read(buf);
1.182 - }
1.183 - catch(IOException ex)
1.184 - {
1.185 - // The connection was probably closed by the remote host
1.186 - // in a non-clean fashion
1.187 - Log.get().info("ChannelReader.processSelectionKey(): " + ex);
1.188 - }
1.189 - catch(Exception ex)
1.190 - {
1.191 - Log.get().warning("ChannelReader.processSelectionKey(): " + ex);
1.192 - }
1.193 -
1.194 - if(read == -1) // End of stream
1.195 - {
1.196 - selKey.cancel();
1.197 - }
1.198 - else if(read > 0) // If some data was read
1.199 - {
1.200 - ConnectionWorker.addChannel(socketChannel);
1.201 - }
1.202 - }
1.203 - }
1.204 - else
1.205 - {
1.206 - // Should not happen
1.207 - Log.get().severe("Should not happen: " + selKey.toString());
1.208 - }
1.209 - }
1.210 -
1.211 + // Process the first pending event
1.212 + while (it.hasNext()) {
1.213 + selKey = (SelectionKey) it.next();
1.214 + channel = (SocketChannel) selKey.channel();
1.215 + conn = Connections.getInstance().get(channel);
1.216 +
1.217 + // Because we cannot lock the selKey as that would cause a deadlock
1.218 + // we lock the connection. To preserve the order of the received
1.219 + // byte blocks a selection key for a connection that has pending
1.220 + // read events is skipped.
1.221 + if (conn == null || conn.tryReadLock()) {
1.222 + // Remove from set to indicate that it's being processed
1.223 + it.remove();
1.224 + if (conn != null) {
1.225 + break; // End while loop
1.226 + }
1.227 + } else {
1.228 + selKey = null;
1.229 + channel = null;
1.230 + conn = null;
1.231 + }
1.232 + }
1.233 + }
1.234 +
1.235 + // Do not lock the selKeys while processing because this causes
1.236 + // a deadlock in sun.nio.ch.SelectorImpl.lockAndDoSelect()
1.237 + if (selKey != null && channel != null && conn != null) {
1.238 + processSelectionKey(conn, channel, selKey);
1.239 + conn.unlockReadLock();
1.240 + }
1.241 +
1.242 + } catch (CancelledKeyException ex) {
1.243 + Log.get().warning("ChannelReader.run(): " + ex);
1.244 + Log.get().log(Level.INFO, "", ex);
1.245 + } catch (Exception ex) {
1.246 + ex.printStackTrace();
1.247 + }
1.248 +
1.249 + // Eventually wait for a register operation
1.250 + synchronized (NNTPDaemon.RegisterGate) {
1.251 + // Do nothing; FindBugs may warn about an empty synchronized
1.252 + // statement, but we cannot use a wait()/notify() mechanism here.
1.253 + // If we used something like RegisterGate.wait() we block here
1.254 + // until the NNTPDaemon calls notify(). But the daemon only
1.255 + // calls notify() if itself is NOT blocked in the listening socket.
1.256 + }
1.257 + } // while(isRunning())
1.258 + }
1.259 +
1.260 + private void processSelectionKey(final NNTPConnection connection,
1.261 + final SocketChannel socketChannel, final SelectionKey selKey)
1.262 + throws InterruptedException, IOException
1.263 + {
1.264 + assert selKey != null;
1.265 + assert selKey.isReadable();
1.266 +
1.267 + // Some bytes are available for reading
1.268 + if (selKey.isValid()) {
1.269 + // Lock the channel
1.270 + //synchronized(socketChannel)
1.271 + {
1.272 + // Read the data into the appropriate buffer
1.273 + ByteBuffer buf = connection.getInputBuffer();
1.274 + int read = -1;
1.275 + try {
1.276 + read = socketChannel.read(buf);
1.277 + } catch (IOException ex) {
1.278 + // The connection was probably closed by the remote host
1.279 + // in a non-clean fashion
1.280 + Log.get().info("ChannelReader.processSelectionKey(): " + ex);
1.281 + } catch (Exception ex) {
1.282 + Log.get().warning("ChannelReader.processSelectionKey(): " + ex);
1.283 + }
1.284 +
1.285 + if (read == -1) // End of stream
1.286 + {
1.287 + selKey.cancel();
1.288 + } else if (read > 0) // If some data was read
1.289 + {
1.290 + ConnectionWorker.addChannel(socketChannel);
1.291 + }
1.292 + }
1.293 + } else {
1.294 + // Should not happen
1.295 + Log.get().severe("Should not happen: " + selKey.toString());
1.296 + }
1.297 + }
1.298 }