diff -r 000000000000 -r 1090e2141798 org/sonews/daemon/ChannelReader.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/org/sonews/daemon/ChannelReader.java	Wed Jul 01 10:48:22 2009 +0200
@@ -0,0 +1,202 @@
+/*
+ *   SONEWS News Server
+ *   see AUTHORS for the list of contributors
+ *
+ *   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 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.sonews.daemon;
+
+import org.sonews.util.Log;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.CancelledKeyException;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.Selector;
+import java.nio.channels.SocketChannel;
+import java.util.Iterator;
+import java.util.Set;
+
+/**
+ * A Thread task listening for OP_READ events from SocketChannels.
+ * @author Christian Lins
+ * @since sonews/0.5.0
+ */
+class ChannelReader extends AbstractDaemon
+{
+
+  private static ChannelReader instance = new ChannelReader();
+
+  /**
+   * @return Active ChannelReader instance.
+   */
+  public static ChannelReader getInstance()
+  {
+    return instance;
+  }
+  
+  private Selector selector = null;
+  
+  protected ChannelReader()
+  {
+  }
+  
+  /**
+   * Sets the selector which is used by this reader to determine the channel
+   * to read from.
+   * @param selector
+   */
+  public void setSelector(final Selector selector)
+  {
+    this.selector = selector;
+  }
+  
+  /**
+   * Run loop. Blocks until some data is available in a channel.
+   */
+  @Override
+  public void run()
+  {
+    assert selector != null;
+
+    while(isRunning())
+    {
+      try
+      {
+        // select() blocks until some SelectableChannels are ready for
+        // processing. There is no need to lock the selector as we have only
+        // one thread per selector.
+        selector.select();
+
+        // Get list of selection keys with pending events.
+        // Note: the selected key set is not thread-safe
+        SocketChannel channel = null;
+        NNTPConnection conn = null;
+        final Set<SelectionKey> selKeys = selector.selectedKeys();
+        SelectionKey selKey = null;
+
+        synchronized (selKeys)
+        {
+          Iterator it = selKeys.iterator();
+
+          // Process the first pending event
+          while (it.hasNext())
+          {
+            selKey = (SelectionKey) it.next();
+            channel = (SocketChannel) selKey.channel();
+            conn = Connections.getInstance().get(channel);
+
+            // Because we cannot lock the selKey as that would cause a deadlock
+            // we lock the connection. To preserve the order of the received
+            // byte blocks a selection key for a connection that has pending
+            // read events is skipped.
+            if (conn == null || conn.tryReadLock())
+            {
+              // Remove from set to indicate that it's being processed
+              it.remove();
+              if (conn != null)
+              {
+                break; // End while loop
+              }
+            }
+            else
+            {
+              selKey = null;
+              channel = null;
+              conn = null;
+            }
+          }
+        }
+
+        // Do not lock the selKeys while processing because this causes
+        // a deadlock in sun.nio.ch.SelectorImpl.lockAndDoSelect()
+        if (selKey != null && channel != null && conn != null)
+        {
+          processSelectionKey(conn, channel, selKey);
+          conn.unlockReadLock();
+        }
+
+      }
+      catch(CancelledKeyException ex)
+      {
+        Log.msg("ChannelReader.run(): " + ex, false);
+        if(Log.isDebug())
+        {
+          ex.printStackTrace();
+        }
+      }
+      catch(Exception ex)
+      {
+        ex.printStackTrace();
+      }
+      
+      // Eventually wait for a register operation
+      synchronized (NNTPDaemon.RegisterGate)
+      {
+      // Do nothing; FindBugs may warn about an empty synchronized 
+      // statement, but we cannot use a wait()/notify() mechanism here.
+      // If we used something like RegisterGate.wait() we block here
+      // until the NNTPDaemon calls notify(). But the daemon only
+      // calls notify() if itself is NOT blocked in the listening socket.
+      }
+    } // while(isRunning())
+  }
+  
+  private void processSelectionKey(final NNTPConnection connection,
+    final SocketChannel socketChannel, final SelectionKey selKey)
+    throws InterruptedException, IOException
+  {
+    assert selKey != null;
+    assert selKey.isReadable();
+    
+    // Some bytes are available for reading
+    if(selKey.isValid())
+    {      
+      // Lock the channel
+      //synchronized(socketChannel)
+      {
+        // Read the data into the appropriate buffer
+        ByteBuffer buf = connection.getInputBuffer();
+        int read = -1;
+        try 
+        {
+          read = socketChannel.read(buf);
+        } 
+        catch(Exception ex) 
+        {
+          Log.msg("ChannelReader.processSelectionKey(): " + ex, false);
+          if(Log.isDebug())
+          {
+            ex.printStackTrace();
+          }
+        }
+        
+        if(read == -1) // End of stream
+        {
+          selKey.cancel();
+        }
+        else if(read > 0) // If some data was read
+        {
+          ConnectionWorker.addChannel(socketChannel);
+        }
+      }
+    }
+    else
+    {
+      // Should not happen
+      Log.msg(selKey, false);
+    }
+  }
+  
+}