| /* |
| * Copyright 1999,2004 The Apache Software Foundation. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.catalina.tribes.transport.nio; |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| import java.nio.channels.SelectionKey; |
| import java.nio.channels.SocketChannel; |
| |
| import org.apache.catalina.tribes.io.ObjectReader; |
| import org.apache.catalina.tribes.transport.Constants; |
| import org.apache.catalina.tribes.transport.WorkerThread; |
| import org.apache.catalina.tribes.ChannelMessage; |
| import org.apache.catalina.tribes.io.ListenCallback; |
| import org.apache.catalina.tribes.io.ClusterData; |
| |
| /** |
| * A worker thread class which can drain channels and echo-back the input. Each |
| * instance is constructed with a reference to the owning thread pool object. |
| * When started, the thread loops forever waiting to be awakened to service the |
| * channel associated with a SelectionKey object. The worker is tasked by |
| * calling its serviceChannel() method with a SelectionKey object. The |
| * serviceChannel() method stores the key reference in the thread object then |
| * calls notify() to wake it up. When the channel has been drained, the worker |
| * thread returns itself to its parent pool. |
| * |
| * @author Filip Hanik |
| * |
| * @version $Revision: 378050 $, $Date: 2006-02-15 12:30:02 -0600 (Wed, 15 Feb 2006) $ |
| */ |
| public class NioReplicationThread extends WorkerThread { |
| |
| private static org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory.getLog( NioReplicationThread.class ); |
| private ByteBuffer buffer = null; |
| private SelectionKey key; |
| private int rxBufSize; |
| public NioReplicationThread (ListenCallback callback) |
| { |
| super(callback); |
| } |
| |
| // loop forever waiting for work to do |
| public synchronized void run() |
| { |
| if ( (getOptions() & OPTION_DIRECT_BUFFER) == OPTION_DIRECT_BUFFER ) { |
| buffer = ByteBuffer.allocateDirect(getRxBufSize()); |
| }else { |
| buffer = ByteBuffer.allocate (getRxBufSize()); |
| } |
| while (isDoRun()) { |
| try { |
| // sleep and release object lock |
| this.wait(); |
| } catch (InterruptedException e) { |
| if(log.isInfoEnabled()) |
| log.info("TCP worker thread interrupted in cluster",e); |
| // clear interrupt status |
| Thread.interrupted(); |
| } |
| if (key == null) { |
| continue; // just in case |
| } |
| try { |
| drainChannel (key); |
| } catch (Exception e) { |
| //this is common, since the sockets on the other |
| //end expire after a certain time. |
| if ( e instanceof IOException ) { |
| //dont spew out stack traces for IO exceptions unless debug is enabled. |
| if (log.isDebugEnabled()) log.debug ("IOException in replication worker, unable to drain channel. Probable cause: Keep alive socket closed.", e); |
| else log.warn ("IOException in replication worker, unable to drain channel. Probable cause: Keep alive socket closed."); |
| } else if ( log.isErrorEnabled() ) { |
| //this is a real error, log it. |
| log.error("Exception caught in TcpReplicationThread.drainChannel.",e); |
| } |
| |
| // close channel and nudge selector |
| try { |
| key.channel().close(); |
| } catch (IOException ex) { |
| log.error("Unable to close channel.",ex); |
| } |
| key.selector().wakeup(); |
| } |
| key = null; |
| // done, ready for more, return to pool |
| getPool().returnWorker (this); |
| } |
| } |
| |
| /** |
| * Called to initiate a unit of work by this worker thread |
| * on the provided SelectionKey object. This method is |
| * synchronized, as is the run() method, so only one key |
| * can be serviced at a given time. |
| * Before waking the worker thread, and before returning |
| * to the main selection loop, this key's interest set is |
| * updated to remove OP_READ. This will cause the selector |
| * to ignore read-readiness for this channel while the |
| * worker thread is servicing it. |
| */ |
| public synchronized void serviceChannel (SelectionKey key) { |
| this.key = key; |
| key.interestOps (key.interestOps() & (~SelectionKey.OP_READ)); |
| key.interestOps (key.interestOps() & (~SelectionKey.OP_WRITE)); |
| this.notify(); // awaken the thread |
| } |
| |
| /** |
| * The actual code which drains the channel associated with |
| * the given key. This method assumes the key has been |
| * modified prior to invocation to turn off selection |
| * interest in OP_READ. When this method completes it |
| * re-enables OP_READ and calls wakeup() on the selector |
| * so the selector will resume watching this channel. |
| */ |
| protected void drainChannel (SelectionKey key) throws Exception { |
| SocketChannel channel = (SocketChannel) key.channel(); |
| int count; |
| buffer.clear(); // make buffer empty |
| ObjectReader reader = (ObjectReader)key.attachment(); |
| // loop while data available, channel is non-blocking |
| while ((count = channel.read (buffer)) > 0) { |
| buffer.flip(); // make buffer readable |
| if ( buffer.hasArray() ) |
| reader.append(buffer.array(),0,count,false); |
| else |
| reader.append(buffer,count,false); |
| buffer.clear(); // make buffer empty |
| } |
| |
| int pkgcnt = reader.count(); |
| |
| if ( pkgcnt > 0 ) { |
| ChannelMessage[] msgs = reader.execute(); |
| for ( int i=0; i<msgs.length; i++ ) { |
| /** |
| * Use send ack here if you want to ack the request to the remote |
| * server before completing the request |
| * This is considered an asynchronized request |
| */ |
| if (ClusterData.sendAckAsync(msgs[i].getOptions())) sendAck(key,channel); |
| try { |
| //process the message |
| getCallback().messageDataReceived(msgs[i]); |
| }catch ( Exception e ) { |
| log.error("Processing of cluster message failed.",e); |
| } |
| /** |
| * Use send ack here if you want the request to complete on this |
| * server before sending the ack to the remote server |
| * This is considered a synchronized request |
| */ |
| |
| if (ClusterData.sendAckSync(msgs[i].getOptions())) sendAck(key,channel); |
| } |
| } |
| |
| |
| |
| |
| if (count < 0) { |
| // close channel on EOF, invalidates the key |
| if ( log.isDebugEnabled() ) log.debug("Channel closed on the remote end, disconnecting"); |
| channel.close(); |
| return; |
| } |
| |
| //acquire the interestOps mutex |
| Object mutex = this.getPool().getInterestOpsMutex(); |
| synchronized (mutex) { |
| // cycle the selector so this key is active again |
| key.selector().wakeup(); |
| // resume interest in OP_READ, OP_WRITE |
| int resumeOps = key.interestOps() | SelectionKey.OP_READ; |
| key.interestOps(resumeOps); |
| } |
| |
| } |
| |
| |
| |
| |
| |
| /** |
| * send a reply-acknowledgement (6,2,3) |
| * @param key |
| * @param channel |
| */ |
| protected void sendAck(SelectionKey key, SocketChannel channel) { |
| |
| try { |
| channel.write(ByteBuffer.wrap(Constants.ACK_COMMAND)); |
| if (log.isTraceEnabled()) { |
| log.trace("ACK sent to " + channel.socket().getPort()); |
| } |
| } catch ( java.io.IOException x ) { |
| log.warn("Unable to send ACK back through channel, channel disconnected?: "+x.getMessage()); |
| } |
| } |
| |
| public void setRxBufSize(int rxBufSize) { |
| this.rxBufSize = rxBufSize; |
| } |
| |
| public int getRxBufSize() { |
| return rxBufSize; |
| } |
| } |