/**
* @param config {@link MessageDispatcher}'s config
* @see org.o3project.odenos.remoteobject.messagingclient.redis.PubSubDriverImpl
*/
public MessageDispatcher(Config config) {
// Config
systemManagerId = config.getSystemManagerId();
eventManagerId = config.getEventManagerId();
sourceDispatcherId = config.getSourceDispatcherId();
mode = config.getMode();
localRequestsToPubSubServer = config.getMode().contains(MODE.LOCAL_REQUESTS_TO_PUBSUB);
// Actor system instantiation.
// The number of woker threads: the max number of remote transactions.
actor = Actor.getInstance(config.getRemoteTransactionsMax());
// Instantiates IPubSubDriver impl. class
ClassLoader classLoader = ClassLoader.getSystemClassLoader();
try {
Class<?> clazz = classLoader.loadClass(config.getPubSubDriverImpl());
Constructor<?> constructor =
clazz.getDeclaredConstructor(Config.class, IMessageListener.class);
driverImpl = (IPubSubDriver) constructor.newInstance(config, this);
} catch (Exception e) {
log.error("class load error", e);
}
// Remote Transactions pool
remoteTransactions = new RemoteTransactions(this, config);
}
/**
* onMessage implementation.
*
* <p>This method has two roles:
*
* <ul>
* <li>Works like a mail transfer agent to transfer a received request or event to {@link
* org.o3project.odenos.remoteobject.RemoteObject}.
* <li>Supports both synchronous and asynchronous messaging.
* </ul>
*/
@Override
public void onMessage(final String channel, byte[] message) {
serial++; // Serial number for incoming messages.
try {
BufferUnpacker upk = msgpack.createBufferUnpacker(message);
// read delivery header.
byte type = upk.readByte();
final int sno = upk.readInt(); // Sequence number for outgoing request messages.
final String sourceObjectId = upk.readString(); // i.e., channel
RemoteObject localObject = null;
Queue<Mail> mailbox = null;
Mail mail = null;
switch (type) {
case TYPE_REQUEST: // Transaction(request): synchronous operation
/*
* --- request --> dispatchRequest() -------> [RemoteObject]
* |
* <-- response --- publishResponseAsync() <-------+
*/
final Request request = upk.read(Request.class);
if (log.isDebugEnabled()) {
log.debug(
"Request received:\n"
+ " MessageDispatcher: {}\n"
+ " sno: {}\n"
+ " channel: {}\n"
+ " method: {}\n"
+ " objectId: {}\n"
+ " sourceObjectId: {}\n"
+ " path: /{}/\n"
+ " body: {}",
sourceDispatcherId,
sno,
channel,
request.method,
request.objectId,
sourceObjectId,
request.path,
request.getBodyValue());
}
// Wraps the request with Mail and deliver it to a mailbox.
String to = request.objectId;
mail = new Mail(serial, sno, to, sourceObjectId, this, request, null);
localObject = localObjectsMap.get(to);
if (localObject != null) {
mailbox = localObject.getMailbox();
synchronized (mailbox) {
mailbox.add(mail);
if (!localObject.isRunning()) {
localObject.setRunning(true);
// Assigns a thread to read a mail in the mailbox.
actor.read(localObject);
}
}
}
break;
case TYPE_RESPONSE: // Transaction(response): synchronous operation
/*
* publishRequestAsync()
* requestSync() -> [RemoteTransaction] ---- request -----> [RemoteObject]
* <-- ^ |
* | publishResponseAsync()
* | |
* +- signalResponse() <-- response --+
*/
Response response = upk.read(Response.class);
if (log.isDebugEnabled()) {
log.debug(
"Response received:\n"
+ " MessageDispatcher: {}\n"
+ " channel: {}\n"
+ " statusCode: {}\n"
+ " body: {}",
sourceDispatcherId,
channel,
response.statusCode,
response.getBodyValue());
}
remoteTransactions.signalResponse(sno, response);
break;
case TYPE_EVENT: // Asynchronous
/*
* publishEventAsync() -- event --> dispatchEvent() --> [RemoteObject]
* :
* [EventSubscriptionMap]
*/
final Event event = upk.read(Event.class);
if (log.isDebugEnabled()) {
log.debug(
"Event received:\n"
+ " MessageDispatcher: {}\n"
+ " channel: {}\n"
+ " body: {}",
sourceDispatcherId,
channel,
event.getBodyValue());
}
// All the subscribers of the channel
final Collection<String> subscribers = subscribersMap.getSubscribers(channel);
if (subscribers == null) { // No subscribers found on the channel
if (log.isDebugEnabled()) {
log.debug("no subscribers subscribing the channel: {}", channel);
}
return; // Silently discards the event
}
// Wraps the event with Mail and deliver it to a mailbox.
for (String subscriber : subscribers) {
localObject = localObjectsMap.get(subscriber);
if (localObject != null) {
mail = new Mail(serial, sno, subscriber, channel, this, null, event);
mailbox = localObject.getMailbox();
synchronized (mailbox) {
mailbox.add(mail);
if (!localObject.isRunning()) {
localObject.setRunning(true);
// Assigns a thread to read a mail in the mailbox.
actor.read(localObject);
}
}
}
}
break;
default:
break;
}
} catch (Exception e) {
log.error("onMessage failed", e);
}
}