/**
* Asynchronous event publication service for requestSync().
*
* <p>requestSync() turns into this method via RemoteMessageTransport.
*
* <p>Remote objects uses this method to publish a request as event asynchronously.
*
* <p>Although this method is asynchronous, {@link RemoteTransactions} provides a synchronous
* method to wait for a response from another remote object.
*/
protected void publishRequestAsync(final int sno, final Request request) throws IOException {
BufferPacker pk = msgpack.createBufferPacker();
// write delivery header.
pk.write(TYPE_REQUEST);
pk.write(sno);
pk.write(getSourceDispatcherId());
// write delivery body.
pk.write(request);
byte[] message = pk.toByteArray();
String channel = request.objectId;
// PUBLISH
driverImpl.publish(channel, message);
if (log.isDebugEnabled()) {
log.debug(
"Request sent:\n"
+ " MessageDispatcher: {}\n"
+ " sno: {}\n"
+ " channel: {}\n"
+ " method: {}\n"
+ " objectId: {}\n"
+ " path: /{}/\n"
+ " body: {}",
sourceDispatcherId,
sno,
channel,
request.method,
request.objectId,
request.path,
request.getBodyValue());
}
}
@Override
protected Response onRequest(final Request req) {
log.debug("onRequest: " + req.method + ", " + req.path);
RequestParser<IActionCallback>.ParsedRequest parsed = parser.parse(req);
if (parsed == null) {
// Transfer Other Component
Pattern pattern = Pattern.compile("^components/.*/.*");
if (pattern.matcher(req.path).matches()) {
String compId = getDestinationCompId(req.path);
String command = getDestinationPath(req.path);
return transferComponent(compId, command, req.method, req.getBodyValue());
}
return new Response(Response.BAD_REQUEST, null);
}
Response response = null;
try {
IActionCallback callback = parsed.getResult();
if (callback == null) {
return new Response(Response.BAD_REQUEST, null);
}
response = callback.process(parsed);
} catch (Exception e) {
log.error("Exception Request: " + req.method + ", " + req.path, e);
response = new Response(Response.BAD_REQUEST, null);
}
if (response == null) {
response = new Response(Response.BAD_REQUEST, null);
}
return response;
}
/**
* 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);
}
}