/**
*
* Copyright 2004 Protique Ltd
*
* 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.codehaus.activemq.transport.vm;
import EDU.oswego.cs.dl.util.concurrent.BoundedLinkedQueue;
import EDU.oswego.cs.dl.util.concurrent.Channel;
import EDU.oswego.cs.dl.util.concurrent.SynchronizedBoolean;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.codehaus.activemq.broker.BrokerConnector;
import org.codehaus.activemq.message.Packet;
import org.codehaus.activemq.message.PacketListener;
import org.codehaus.activemq.transport.TransportChannelListener;
import org.codehaus.activemq.transport.TransportChannelSupport;
import javax.jms.JMSException;
/**
* A VM implementation of a TransportChannel
*
* @version $Revision: 1.22 $
*/
public class VmTransportChannel extends TransportChannelSupport implements Runnable {
private static final Log log = LogFactory.getLog(VmTransportChannel.class);
private static final Object TERMINATE = new Object();
private static int lastThreadId = 0; // To number the threads.
// properties
private Channel sendChannel;
private Channel receiveChannel;
private int sendCapacity = 10;
private int receiveCapacity = 10;
private boolean asyncSend = false;
// state
private SynchronizedBoolean closed;
private SynchronizedBoolean started;
private Thread thread; //need to change this - and use a thread pool
private PacketListener sendListener;
private VmTransportChannel clientSide;
public VmTransportChannel() {
closed = new SynchronizedBoolean(false);
started = new SynchronizedBoolean(false);
}
public VmTransportChannel(Channel sendChannel, Channel receiveChannel) {
this();
this.sendChannel = sendChannel;
this.receiveChannel = receiveChannel;
}
public VmTransportChannel(int capacity) {
this(new BoundedLinkedQueue(capacity), new BoundedLinkedQueue(capacity));
}
public void start() throws JMSException {
if (started.commit(false, true)) {
if (isAsyncSend()) {
// lets force the lazy construction
// as we sometimes need to create these early when
// wiring together with a server side channel
getSendChannel();
getReceiveChannel();
thread = new Thread(this, "VM Transport: " + getNextThreadId());
if (isServerSide()) {
thread.setDaemon(true);
}
thread.start();
}
}
}
public void stop() {
if (closed.commit(false, true)) {
super.stop();
try {
// to close the channel, lets send a null
if (sendChannel != null) {
sendChannel.put(TERMINATE);
}
if (receiveChannel != null) {
receiveChannel.put(TERMINATE);
}
if (thread != null) {
// lets wait for the receive thread to terminate
thread.join();
}
}
catch (Exception e) {
log.trace(toString() + " now closed with exception: " + e);
}
}
}
/**
* Asynchronously send a Packet
*
* @param packet
* @throws JMSException
*/
public void asyncSend(Packet packet) throws JMSException {
if (sendChannel != null) {
while (true) {
try {
sendChannel.put(packet);
break;
}
catch (InterruptedException e) {
// continue
}
}
}
else {
if (sendListener == null) {
if (clientSide != null) {
sendListener = clientSide.createPacketListenerSender();
}
}
if (sendListener != null) {
sendListener.consume(packet);
}
else {
throw new JMSException("No sendListener available");
}
}
}
public boolean isMulticast() {
return false;
}
/**
* reads packets from a Socket
*/
public void run() {
while (!closed.get()) {
try {
Object answer = receiveChannel.take();
if (answer == TERMINATE) {
log.trace("The socket peer is now closed");
stop();
return;
}
else if (answer != null) {
Packet packet = (Packet) answer;
// we might have just got a packet in but we've already shut down
if (closed.get()) {
break;
}
doConsumePacket(packet);
}
}
catch (InterruptedException e) {
// continue
}
}
}
/**
* pretty print for object
*
* @return String representation of this object
*/
public String toString() {
return "VmTransportChannel: " + sendChannel;
}
/**
* Connects the client side transport channel with the broker
*/
public void connect(BrokerConnector brokerConnector) throws JMSException {
TransportChannelListener listener = (TransportChannelListener) brokerConnector;
VmTransportChannel serverSide = createServerSide();
listener.addClient(serverSide);
serverSide.start();
}
/**
* Creates the server side version of this client side channel. On the server side
* the client's side sendChannel is the receiveChannel and vice versa
*
* @return
*/
public VmTransportChannel createServerSide() throws JMSException {
VmTransportChannel channel = new VmTransportChannel(getReceiveChannel(), getSendChannel());
channel.clientSide = this;
return channel;
}
public void setPacketListener(PacketListener listener) {
super.setPacketListener(listener);
if (clientSide != null) {
clientSide.sendListener = listener;
}
}
/**
* Can this wireformat process packets of this version
* @param version the version number to test
* @return true if can accept the version
*/
public boolean canProcessWireFormatVersion(int version){
return true;
}
/**
* @return the current version of this wire format
*/
public int getCurrentWireFormatVersion(){
return 1;
}
// Properties
//-------------------------------------------------------------------------
public int getReceiveCapacity() {
return receiveCapacity;
}
public void setReceiveCapacity(int receiveCapacity) {
this.receiveCapacity = receiveCapacity;
}
public int getSendCapacity() {
return sendCapacity;
}
public void setSendCapacity(int sendCapacity) {
this.sendCapacity = sendCapacity;
}
public boolean isAsyncSend() {
return asyncSend;
}
public void setAsyncSend(boolean asyncSend) {
this.asyncSend = asyncSend;
}
public Channel getSendChannel() {
if (isAsyncSend()) {
if (sendChannel == null) {
sendChannel = createChannel(getSendCapacity());
}
}
return sendChannel;
}
public void setSendChannel(Channel sendChannel) {
this.sendChannel = sendChannel;
}
public Channel getReceiveChannel() {
if (isAsyncSend()) {
if (receiveChannel == null) {
receiveChannel = createChannel(getReceiveCapacity());
}
}
return receiveChannel;
}
public void setReceiveChannel(Channel receiveChannel) {
this.receiveChannel = receiveChannel;
}
// Implementation methods
//-------------------------------------------------------------------------
protected static synchronized int getNextThreadId() {
return lastThreadId++;
}
protected Channel createChannel(int capacity) {
return new BoundedLinkedQueue(capacity);
}
/**
* Creates a sender PacketListener which handles any receipts then delegates
* to the ultimate PacketListener (typically the JMS client)
*
* @return
*/
protected PacketListener createPacketListenerSender() {
return new PacketListener() {
public void consume(Packet packet) {
doConsumePacket(packet, getPacketListener());
}
};
}
protected void doClose(Exception ex) {
if (!closed.get()) {
JMSException jmsEx = new JMSException("Error reading socket: " + ex.getMessage());
jmsEx.setLinkedException(ex);
onAsyncException(jmsEx);
stop();
}
}
}