/*
* 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.group.interceptors;
import org.apache.catalina.tribes.Channel;
import org.apache.catalina.tribes.ChannelException;
import org.apache.catalina.tribes.ChannelMessage;
import org.apache.catalina.tribes.Member;
import org.apache.catalina.tribes.UniqueId;
import org.apache.catalina.tribes.group.ChannelInterceptorBase;
import org.apache.catalina.tribes.group.InterceptorPayload;
import org.apache.catalina.tribes.transport.bio.util.FastQueue;
import org.apache.catalina.tribes.transport.bio.util.LinkObject;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
/**
*
* The message dispatcher is a way to enable asynchronous communication
* through a channel. The dispatcher will look for the
* <code>Channel.SEND_OPTIONS_ASYNCHRONOUS</code> flag to be set, if it is, it
* will queue the message for delivery and immediately return to the sender.
*
* @author Filip Hanik
* @version 1.0
*/
public class MessageDispatchInterceptor extends ChannelInterceptorBase implements Runnable {
private static final Log log = LogFactory.getLog(MessageDispatchInterceptor.class);
protected long maxQueueSize = 1024*1024*64; //64MB
protected final FastQueue queue = new FastQueue();
protected volatile boolean run = false;
protected Thread msgDispatchThread = null;
protected long currentSize = 0;
protected boolean useDeepClone = true;
protected boolean alwaysSend = true;
public MessageDispatchInterceptor() {
setOptionFlag(Channel.SEND_OPTIONS_ASYNCHRONOUS);
}
@Override
public void sendMessage(Member[] destination, ChannelMessage msg, InterceptorPayload payload)
throws ChannelException {
boolean async = (msg.getOptions() &
Channel.SEND_OPTIONS_ASYNCHRONOUS) == Channel.SEND_OPTIONS_ASYNCHRONOUS;
if ( async && run ) {
if ( (getCurrentSize()+msg.getMessage().getLength()) > maxQueueSize ) {
if ( alwaysSend ) {
super.sendMessage(destination,msg,payload);
return;
} else {
throw new ChannelException("Asynchronous queue is full, reached its limit of " +
maxQueueSize +" bytes, current:" + getCurrentSize() + " bytes.");
}//end if
}//end if
//add to queue
if ( useDeepClone ) msg = (ChannelMessage)msg.deepclone();
if (!addToQueue(msg, destination, payload) ) {
throw new ChannelException(
"Unable to add the message to the async queue, queue bug?");
}
addAndGetCurrentSize(msg.getMessage().getLength());
} else {
super.sendMessage(destination, msg, payload);
}
}
public boolean addToQueue(ChannelMessage msg, Member[] destination,
InterceptorPayload payload) {
return queue.add(msg,destination,payload);
}
public LinkObject removeFromQueue() {
return queue.remove();
}
public void startQueue() {
msgDispatchThread = new Thread(this);
msgDispatchThread.setName("MessageDispatchInterceptor.MessageDispatchThread");
msgDispatchThread.setDaemon(true);
msgDispatchThread.setPriority(Thread.MAX_PRIORITY);
queue.setEnabled(true);
run = true;
msgDispatchThread.start();
}
public void stopQueue() {
run = false;
msgDispatchThread.interrupt();
queue.setEnabled(false);
setAndGetCurrentSize(0);
}
@Override
public void setOptionFlag(int flag) {
if ( flag != Channel.SEND_OPTIONS_ASYNCHRONOUS ) {
log.warn("Warning, you are overriding the asynchronous option " +
"flag, this will disable the Channel.SEND_OPTIONS_ASYNCHRONOUS " +
"that other apps might use.");
}
super.setOptionFlag(flag);
}
public void setMaxQueueSize(long maxQueueSize) {
this.maxQueueSize = maxQueueSize;
}
public void setUseDeepClone(boolean useDeepClone) {
this.useDeepClone = useDeepClone;
}
public long getMaxQueueSize() {
return maxQueueSize;
}
public boolean getUseDeepClone() {
return useDeepClone;
}
public long getCurrentSize() {
return currentSize;
}
public long addAndGetCurrentSize(long inc) {
synchronized (this) {
currentSize += inc;
return currentSize;
}
}
public long setAndGetCurrentSize(long value) {
synchronized (this) {
currentSize = value;
return value;
}
}
@Override
public void start(int svc) throws ChannelException {
//start the thread
if (!run ) {
synchronized (this) {
// only start with the sender
if ( !run && ((svc & Channel.SND_TX_SEQ)==Channel.SND_TX_SEQ) ) {
startQueue();
}//end if
}//sync
}//end if
super.start(svc);
}
@Override
public void stop(int svc) throws ChannelException {
//stop the thread
if ( run ) {
synchronized (this) {
if ( run && ((svc & Channel.SND_TX_SEQ)==Channel.SND_TX_SEQ)) {
stopQueue();
}//end if
}//sync
}//end if
super.stop(svc);
}
@Override
public void run() {
while ( run ) {
LinkObject link = removeFromQueue();
if ( link == null ) continue; //should not happen unless we exceed wait time
while ( link != null && run ) {
link = sendAsyncData(link);
}//while
}//while
}//run
protected LinkObject sendAsyncData(LinkObject link) {
ChannelMessage msg = link.data();
Member[] destination = link.getDestination();
try {
super.sendMessage(destination,msg,null);
try {
if (link.getHandler() != null) {
link.getHandler().handleCompletion(new UniqueId(msg.getUniqueId()));
}
} catch ( Exception ex ) {
log.error("Unable to report back completed message.",ex);
}
} catch ( Exception x ) {
ChannelException cx = null;
if ( x instanceof ChannelException ) cx = (ChannelException)x;
else cx = new ChannelException(x);
if ( log.isDebugEnabled() ) log.debug("Error while processing async message.",x);
try {
if (link.getHandler() != null) {
link.getHandler().handleError(cx, new UniqueId(msg.getUniqueId()));
}
} catch ( Exception ex ) {
log.error("Unable to report back error message.",ex);
}
} finally {
addAndGetCurrentSize(-msg.getMessage().getLength());
link = link.next();
}//try
return link;
}
public boolean isAlwaysSend() {
return alwaysSend;
}
public void setAlwaysSend(boolean alwaysSend) {
this.alwaysSend = alwaysSend;
}
}