here are some thoughts regarding the JBoss ESB/jBPM connection: First, these tools are in our company (Wincor Nixdorf, ATMs and Retail Cash Management, Germany) of great help. It makes sense to have two perspective on processes, a business one and a technical one. Therefore it is a useful thing that you can jump between both kind of systems (a process machine and an ESB).
But there is also a problem with that: Recently I figured out (accidentially) that the possibility to jump from the ESB back into jBPM by applying the "SignalCommand" command of the BpmProcessor has been removed in JBoss ESB 4.5. Currently we're using JBoss ESB 4.4 in a JBoss AS 4.2.3, but of course we need to have methods that are maintained for certain in future.
So I applied the jbpmCallback action and service, which works fine (except one point, but for this I will write another posting in the Developer's forum), but it is not as convenient as the SignalCommand/BpmProcessor. Also, what annoyed me a bit, is that I had to go way down into the source code to figure out how it actually works and to get it to run, since the documentation for this special service is quite poor (one of the few things I found is that: http://www.jboss.org/community/wiki/JBossESBjBPMIntegration). For example, what is not described is that the process information necessary to get back to the running process instance is expected at Message.getHeader.getCall().getTo() instead of Message.getHeader().getCall().getReplyTo(), where it is copied to when jBPM jumps to the ESB (when the ESBActionHandler is used in jBPM). Thus, you have to manually copy this information in order to call back a running a jBPM process.
So, my strong suggestion and recommendation, at least from an industrial perspective, is to support a stable, easy-to use and well documentend way for getting back and forth between jBPM and the ESB. Also changes in this part of the functionality should be make public and not left to blog entries hidden somewhere in the internet. But maybe I have missed that in the official documents.
We at Wincor Nixdorf enjoy the JBoss Suite very much, and it would be great if you could support us in this way!
Looking forward to seeing your comments, cheers,
Andre Skusa, Paderborn, Germany