messaging

I've been working with JMS and ActiveMQ. Everything is working wonders. I am not using spring, nor can I. The interface javax.jms.MessageListener has only one method, onMessage . From within a implementation, there is a chance an exception will be thrown. If in fact an exception gets thrown, then I say the message wasn't properly processed and needs to be re-tried. So, I need ActiveMQ to wait for a little while and then, retry. i.e. I need the thrown exception to rollback the JMS transaction. How can I accomplish such a behaviour? Maybe there is some configuration in ActiveMQ I wasn't able to

I'm looking into building a real-time chat app for iPhone (but this question applies to Android and other devices as well) Basically I want the app to receive realtime messages while it's open as well as while it's closed, just like the iPhone's own "Message" app. When it's closed I can use the native push notification services like APNS, and when the app is open, I can run my own websockets server or use 3rd party providers like PubNub or Pusher, which is what I've been doing actually. Then I wondered: Why can't I completely rely on APNS for the real-time messaging, both while the app is open

I've been working with Android for well over a year now, but I still have trouble determining when different types of messaging/communication between processes/threads should be used. I'm mainly talking about broadcasting Intents, using AIDL for services , using Handlers to send messages and socket communication. Many of these tools can be used to accomplish similar tasks, but which is better suited to particular situations? This is a pretty open ended question, but let me take a shot at describing how I see the intra/inter application communication working best. One of the key aspects of

I'm developing a set of applications that work together to create a system for processing metering data. There's several reasons I want to have them loosely coupled and the system should be extensible by third parties, so the apps will be tied together via messaging. I'm looking for a messaging system that offers bindings in (at least) C#, Java and Python and supports messaging patterns like Publish-Subscribe, Guaranteed Delivery, Selective Consumer (like Peek in .Net Messaging). As far as I could find out, there's nothing wrong with JMS or .Net Messaging, it's just that they are for .Net /

Does anyone have any experience of communicating with IPython kernels from outside of Python? If I were trying to send messages from a Python app to an IPython kernel, I'd use the zmq.kernelmanager API. As it is, I'll obviously need to write my own kernel manager in another language, but I can't find the information that I'm looking for about the low-level messaging protocols. Is there an official spec or a 'cheat sheet' that documents the structure of the actual messages that get sent over 0MQ? This page describes a higher-level protocol than what I'm looking for... Will I have to manually

All of the examples of Kafka | producers show the ProducerRecord 's key/value pair as not only being the same type (all examples show <String,String> ), but the same value . For example: producer.send(new ProducerRecord<String, String>("someTopic", Integer.toString(i), Integer.toString(i))); But in the Kafka docs, I can't seem to find where the key/value concept (and its underlying purpose/utility) is explained. In traditional messaging (ActiveMQ, RabbitMQ, etc.) I've always fired a message at a particular topic/queue/exchange. But Kafka is the first broker that seems to require key/value

I am new to JMS . As far as I understood Consumers are capable of picking messages from queue/topic. So why do you need a MessageListener because Consumers will know when they have picked up messages? What is the practical use of such a MessageListener ? Edit:From the Javadoc of MessageListener : A MessageListener object is used to receive asynchronously delivered messages. Each session must insure that it passes messages serially to the listener. This means that a listener assigned to one or more consumers of the same session can assume that the onMessage method is not called with the next