/*
* 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
*/
package org.apache.catalina.tribes.group.interceptors;
import java.util.Arrays;
import java.util.HashMap;
import org.apache.catalina.tribes.ChannelException;
import org.apache.catalina.tribes.ChannelMessage;
import org.apache.catalina.tribes.InterceptorPayload;
import org.apache.catalina.tribes.Member;
import org.apache.catalina.tribes.group.ChannelInterceptorBase;
import org.apache.catalina.tribes.io.XByteBuffer;
import java.util.Collection;
import java.util.ArrayList;
import java.util.Set;
/**
*
* The fragmentation interceptor splits up large messages into smaller messages and assembles them on the other end.
* This is very useful when you don't want large messages hogging the sending sockets
* and smaller messages can make it through.
*
* <br><b>Configuration Options</b><br>
* OrderInteceptor.expire=<milliseconds> - how long do we keep the fragments in memory and wait for the rest to arrive<b>default=60,000ms -> 60seconds</b>
* This setting is useful to avoid OutOfMemoryErrors<br>
* OrderInteceptor.maxSize=<max message size> - message size in bytes <b>default=1024*100 (around a tenth of a MB)</b><br>
* @author Filip Hanik
* @version 1.0
*/
public class FragmentationInterceptor extends ChannelInterceptorBase {
private static org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory.getLog( FragmentationInterceptor.class );
protected HashMap fragpieces = new HashMap();
private int maxSize = 1024*100;
private long expire = 1000 * 60; //one minute expiration
public void sendMessage(Member[] destination, ChannelMessage msg, InterceptorPayload payload) throws ChannelException {
int size = msg.getMessage().getLength();
boolean frag = (size>maxSize);
if ( frag ) {
frag(destination, msg, payload);
}
else {
//byte[] flag = XByteBuffer.toBytes(frag);
//msg.getMessage().append(flag,0,flag.length);
msg.getMessage().append(frag);
super.sendMessage(destination, msg, payload);
}
}
public void messageReceived(ChannelMessage msg) {
boolean isFrag = XByteBuffer.toBoolean(msg.getMessage().getBytesDirect(),msg.getMessage().getLength()-1);
msg.getMessage().trim(1);
if ( isFrag ) {
defrag(msg);
} else {
super.messageReceived(msg);
}
}
public FragCollection getFragCollection(FragKey key, ChannelMessage msg) {
FragCollection coll = (FragCollection)fragpieces.get(key);
if ( coll == null ) {
synchronized (fragpieces) {
coll = (FragCollection)fragpieces.get(key);
if ( coll == null ) {
coll = new FragCollection(msg);
fragpieces.put(key, coll);
}
}
}
return coll;
}
public void removeFragCollection(FragKey key) {
fragpieces.remove(key);
}
public void defrag(ChannelMessage msg ) {
FragKey key = new FragKey(msg.getUniqueId());
FragCollection coll = getFragCollection(key,msg);
coll.addMessage(msg);
if ( coll.complete() ) {
removeFragCollection(key);
ChannelMessage complete = coll.assemble();
super.messageReceived(complete);
}
}
public void frag(Member[] destination, ChannelMessage msg, InterceptorPayload payload) throws ChannelException {
int size = msg.getMessage().getLength();
int count = ((size / maxSize )+(size%maxSize==0?0:1));
ChannelMessage[] messages = new ChannelMessage[count];
int remaining = size;
for ( int i=0; i<count; i++ ) {
ChannelMessage tmp = msg.clone();
int offset = (i*maxSize);
int length = Math.min(remaining,maxSize);
tmp.getMessage().clear();
tmp.getMessage().append(msg.getMessage().getBytesDirect(),offset,length);
//add the msg nr
//tmp.getMessage().append(XByteBuffer.toBytes(i),0,4);
tmp.getMessage().append(i);
//add the total nr of messages
//tmp.getMessage().append(XByteBuffer.toBytes(count),0,4);
tmp.getMessage().append(count);
//add true as the frag flag
//byte[] flag = XByteBuffer.toBytes(true);
//tmp.getMessage().append(flag,0,flag.length);
tmp.getMessage().append(true);
messages[i] = tmp;
remaining -= length;
}
for ( int i=0; i<messages.length; i++ ) {
super.sendMessage(destination,messages[i],payload);
}
}
public void heartbeat() {
try {
Set set = fragpieces.keySet();
Object[] keys = set.toArray();
for ( int i=0; i<keys.length; i++ ) {
FragKey key = (FragKey)keys[i];
if ( key != null && key.expired(getExpire()) )
removeFragCollection(key);
}
}catch ( Exception x ) {
if ( log.isErrorEnabled() ) {
log.error("Unable to perform heartbeat clean up in the frag interceptor",x);
}
}
super.heartbeat();
}
public int getMaxSize() {
return maxSize;
}
public long getExpire() {
return expire;
}
public void setMaxSize(int maxSize) {
this.maxSize = maxSize;
}
public void setExpire(long expire) {
this.expire = expire;
}
public static class FragCollection {
private long received = System.currentTimeMillis();
private ChannelMessage msg;
private XByteBuffer[] frags;
public FragCollection(ChannelMessage msg) {
//get the total messages
int count = XByteBuffer.toInt(msg.getMessage().getBytesDirect(),msg.getMessage().getLength()-4);
frags = new XByteBuffer[count];
this.msg = msg;
}
public void addMessage(ChannelMessage msg) {
//remove the total messages
msg.getMessage().trim(4);
//get the msg nr
int nr = XByteBuffer.toInt(msg.getMessage().getBytesDirect(),msg.getMessage().getLength()-4);
//remove the msg nr
msg.getMessage().trim(4);
frags[nr] = msg.getMessage();
}
public boolean complete() {
boolean result = true;
for ( int i=0; (i<frags.length) && (result); i++ ) result = (frags[i] != null);
return result;
}
public ChannelMessage assemble() {
if ( !complete() ) throw new IllegalStateException("Fragments are missing.");
int buffersize = 0;
for (int i=0; i<frags.length; i++ ) buffersize += frags[i].getLength();
XByteBuffer buf = new XByteBuffer(buffersize,false);
msg.setMessage(buf);
for ( int i=0; i<frags.length; i++ ) {
msg.getMessage().append(frags[i].getBytesDirect(),0,frags[i].getLength());
}
return msg;
}
public boolean expired(long expire) {
return (System.currentTimeMillis()-received)>expire;
}
}
public static class FragKey {
private byte[] uniqueId;
private long received = System.currentTimeMillis();
public FragKey(byte[] id ) {
this.uniqueId = id;
}
public int hashCode() {
return XByteBuffer.toInt(uniqueId,0);
}
public boolean equals(Object o ) {
if ( o instanceof FragKey ) {
return Arrays.equals(uniqueId,((FragKey)o).uniqueId);
} else return false;
}
public boolean expired(long expire) {
return (System.currentTimeMillis()-received)>expire;
}
}
}