messaging

MQ Queue with multiple consumers but only one active

由 笑着哭i 提交于 2019-12-06 04:03:17
问题 We have one MQ Queue which receives messages from an external system out of our control. Our system processing the incoming messages is a critical one and needs to be up and running 27x7 no matter what. The order in which the incoming messages are processed is also not negotiable which means we need to process them in exactly the order they arrived. To make sure our system is 100% available we deployed our system to a bunch of physical machines able to process those messages. Once the

How to prevent a control from changing Z order?

由 China☆狼群 提交于 2019-12-06 03:03:36
I have user control in .Net where I use a hit test in WndProc to allow resizing it in runtime with the mouse. The problem is that after the hit test succedes (mouse press, drag to resize, mouse release) the control jumps upwards in the Z order and ruins it position in the form. I need the hit test since it's a very customized control. Is there a way in WndProc to stop the control from changing it's Z order ? Thanks. The hit test code: protected override void WndProc(ref Message m) { if (!DesignMode && Sizeable && (m.Msg == Win32Wrapper.WM_NCHITTEST)) { Point Hit = new Point((int)m.LParam &

Design Help – Polymorphic Event Handling

由 不想你离开。 提交于 2019-12-06 02:58:34
问题 Design Question – Polymorphic Event Handling I’m currently trying to reduce the number of Event Handles in my current project. We have multiple systems that send data over USB. I currently have a routine to read in the messages and parse the initial header details to determine which system the message came from. The headers are a little different, so the EventArgs I created are not the same. Then I notify all “observers” of the change. So what I have right now is the following: public enum

Is there an use case for non-blocking receive when I have threads?

由 你。 提交于 2019-12-06 02:20:30
问题 I know non-blocking receive is not used as much in message passing, but still some intuition tells me, it is needed. Take for example GUI event driven applications, you need some way to wait for a message in a non-blocking way, so your program can execute some computations. One of the ways to solve this is to have a special thread with message queue. Is there some use case, where you would really need non-blocking receive even if you have threads? 回答1: Threads work differently than non

Is it necessary to use as few queues as possible And solutions for web messaging

由 让人想犯罪 __ 提交于 2019-12-06 01:59:51
I read in forum that while implementing any application using AMQP it is necessary to use fewer queues. So would I be completely wrong to assume that if I were cloning twitter I would have a unique and durable queue for each user signing up? It just seems the most natural approach and if not assign a unique queue for each user how would one design something like that. What is the most used approach for web messaging. I see RabbitHUb and Rabbit WebHooks but Webhooks doesn't seem to be a scalable solution. i am working with Rails and my AMQP server as running as a Daemon. In RabbitMQ, queues are

JMS - How do message selectors work with multiple queue and topic consumers?

由 一曲冷凌霜 提交于 2019-12-05 23:43:55
问题 Say you have a JMS queue, and multiple consumers are watching the queue for messages. You want one of the consumers to get all of a particular type of message, so you decide to employ message selectors. For example, you define a property to go in your JMS message header named, targetConsumer . Your message selector, which you apply to the consumer known as, A , is something like WHERE targetConsumer = 'CONSUMER_A' . It's clear that consumer A will now just grab messages with the property set

Does SignalR support the Publish/Subscribe messaging paradigm?

由 蓝咒 提交于 2019-12-05 23:15:52
I want to use pub-sub messaging between multiple servers in a web farm to maintain their local (ASP.NET) caches in sync. Could this be easily done with SignalR? If it is possible, how can I do so? 来源： https://stackoverflow.com/questions/9449601/does-signalr-support-the-publish-subscribe-messaging-paradigm

How to connect JMS queues from JBOSS 4 and 5?

由 丶灬走出姿态 提交于 2019-12-05 20:50:01
I have a server on which a Jboss 4.2.2 and a Jboss 5.1.0 runs. The problem is that a 3rd party is not able to upgrade its application to Jboss 5.1.0 in the near future, for us it is a simple matter. Unfortunately we need to send and receive some JMS messages from the third party app running on Jboss 4.2.2. What is the easiest way to enable the transfer of JMS messages between JbossMQ and JbossMessaging? I think I found the solution for my problem. The JBOSS documentation has a chapter to migrate messages between JBOSS Messaging and JBOSS MQ: http://www.redhat.com/docs/en-US/JBoss_Enterprise

Is Spring-AMQP re-queue message count JVM based?

由 泪湿孤枕 提交于 2019-12-05 18:43:52
I was poking around the rabbitmq documentation, and it seems that rabbitmq does not handle message redelivery count. If I were to manually ACK/NACK messages, I would need to either keep the retry count in memory (say, by using correlationId as the unique key in a map), or by setting my own header in the message, and redelivering it (thus putting it at the end of the queue) However, this is a case that spring handles. Specifically, I am referring to RetryInterceptorBuilder.stateful().maxAttempts(x). Is this count specific to a JVM though, or is it manipulating the message somehow? For example,

Load pdf obtained as event.data from cross document messaging

由 蓝咒 提交于 2019-12-05 16:50:51
Easy points for someone who knows the answer. My code successfully downloads a pdf from a website via cross document messaging. However, I want to now display the pdf in the browser, possibly in an iframe or data object. Possibly I would need to know the local url that the pdf is stored as once downloaded. Please help, probably easy points. See the fiddle here for my code. IMPORTANT: Because I want to download the file I do not want to simply make client.src="http://ops.epo.org/3.0/rest-services/published-data/images/US/7123345/B2/thumbnail.pdf?Range=1" HTML code: <input type="button" onclick=
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