> I wish there is a JMS-INTEREST list to post this message. Well, there is... > - perform event/alert notification from EJB server back to client PC. > The driver is that there will be 2000 users of the system, > some of them need to be notified of important event during server > processing (business rule enforcement, etc) at real time. client > polling is not acceptable Therefore we need a "callback" capability > from EJB server to client JMS pub/sub is most likely what you want if you talk about "real-time". You'll design some topic names for the various event groups, and let the "clients" (JMS talks about consumers instead) subscribe to the topic(s). Messaging is all about "reversing", i.e. producers calling consumers to deliver messages. To be precise, the MOM calls the consumers, and the producers deliver their messages to the MOM, since messaging is also all about decoupling the components. Because of this "callback"-like architecture, going through firewalls and proxies gives us JMS vendors the headaches (in order to avoid you getting one...). > - perform async calls from EJBean A to EJBean B & C. The driver is that > A need to call B.foo() and C.bar() to collect info. The order of the > call is not important, but B.foo & C.bar are slow in access DB. So we > want to make async/non-blocking calls with B.foo and C.bar in > parallel. > B & C will notify A when they finish, so A can carry on with the rest > of process. (Essentaily something similar to CORBA (Asynchronous > Messaging Interface) AMI) On first sight, JMS request/reply is what you need: A (blocking) request is sent to a topic (not to a specific server). Potential servers are listening on the topic, and can choose to answer (either the entire answer or various parts of it). At the end, JMS delivers an answer back to the caller. That's where JMS falls short: It only delivers the first answer back, not all of them (and you need two). The SoftWired iBus (http://www.softwired-inc.com/iBus/) has an additional call which returns an array of answers, not just the first one. The caller is blocked until all answers are in (or until a configurable timeout occurs). This is what you need to accomplish your goal. ---------------------------------------------------------------------- Martin Erzberger, SoftWired, Technoparkstrasse 1, CH-8005 Zurich Email: [EMAIL PROTECTED] | WWW: http://www.softwired-inc.com Office: +41-1-445-2370 | Fax: +41-1-445-2372 � Mobile: +41-79-402-2607 -------------- Need a pure Java software bus? ----------------- ------- Look at http://www.softwired-inc.com/ibus ! --------- =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff EJB-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help".
