/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.bio;
import org.apache.catalina.tribes.io.ObjectReader;
import org.apache.catalina.tribes.transport.Constants;
import org.apache.catalina.tribes.transport.AbstractRxTask;
import java.net.Socket;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.catalina.tribes.io.ListenCallback;
import org.apache.catalina.tribes.ChannelMessage;
import org.apache.catalina.tribes.io.ChannelData;
import org.apache.catalina.tribes.io.BufferPool;
/**
* 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
*
*
*/
public class BioReplicationTask extends AbstractRxTask {
protected static org.apache.juli.logging.Log log = org.apache.juli.logging.LogFactory.getLog( BioReplicationTask.class );
protected Socket socket;
protected ObjectReader reader;
public BioReplicationTask (ListenCallback callback) {
super(callback);
}
// loop forever waiting for work to do
public synchronized void run()
{
if ( socket == null ) return;
try {
drainSocket();
} catch ( Exception x ) {
log.error("Unable to service bio socket");
}finally {
try {socket.close();}catch ( Exception ignore){}
try {reader.close();}catch ( Exception ignore){}
reader = null;
socket = null;
}
// done, ready for more, return to pool
if ( getTaskPool() != null ) getTaskPool().returnWorker (this);
}
public synchronized void serviceSocket(Socket socket, ObjectReader reader) {
this.socket = socket;
this.reader = reader;
this.notify(); // awaken the thread
}
protected void execute(ObjectReader reader) throws Exception{
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 (ChannelData.sendAckAsync(msgs[i].getOptions())) sendAck(Constants.ACK_COMMAND);
try {
//process the message
getCallback().messageDataReceived(msgs[i]);
/**
* 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 (ChannelData.sendAckSync(msgs[i].getOptions())) sendAck(Constants.ACK_COMMAND);
}catch ( Exception x ) {
if (ChannelData.sendAckSync(msgs[i].getOptions())) sendAck(Constants.FAIL_ACK_COMMAND);
log.error("Error thrown from messageDataReceived.",x);
}
if ( getUseBufferPool() ) {
BufferPool.getBufferPool().returnBuffer(msgs[i].getMessage());
msgs[i].setMessage(null);
}
}
}
}
/**
* 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 drainSocket () throws Exception {
InputStream in = socket.getInputStream();
// loop while data available, channel is non-blocking
byte[] buf = new byte[1024];
int length = in.read(buf);
while ( length >= 0 ) {
int count = reader.append(buf,0,length,true);
if ( count > 0 ) execute(reader);
length = in.read(buf);
}
}
/**
* send a reply-acknowledgement (6,2,3)
*/
protected void sendAck(byte[] command) {
try {
OutputStream out = socket.getOutputStream();
out.write(command);
out.flush();
if (log.isTraceEnabled()) {
log.trace("ACK sent to " + socket.getPort());
}
} catch ( java.io.IOException x ) {
log.warn("Unable to send ACK back through channel, channel disconnected?: "+x.getMessage());
}
}
public void close() {
setDoRun(false);
try {socket.close();}catch ( Exception ignore){}
try {reader.close();}catch ( Exception ignore){}
reader = null;
socket = null;
super.close();
}
}