Seeking Suggestion

Question

Hello All,
     I am a newbie to SOA and OpenESB.I want to take some advice to get an initial direction to proceed. Let me explain my requirement first.
     I work as software developer in a business rules product software company. It bascically has a rule engine which is used to evaluate certain input conditions and return appropriate actions based on those.This engine is already deployed as a web-service and i can invoke it via axis server.
     Now my task is to integrate this rule engine in OpenESB architecture.As I am going through the specs and the demo ,i figured out few options:
1) the rule engine which is already deployed as a web service can be called from outside the JBI environment and used as an external service.
2)the rule engine can be installed as an internal service to jbi environment.
is the second option viable?...actually it is requirement not to use the axis server and that would mean i cant use the present webservice engine.
So,wat is the possibility of using my existing engine classes inside JBI env. What exactly I would need to do. And could you please suggest some document or demo which can help me in this regard.
Any help in this regard will be highly appreciated.
Regards,
Kunal Chakrabarty
a novice to OpenESB and JBI.

Answer 1

Hello All,
I am a newbie to SOA and OpenESB.I want to take some
e advice to get an initial direction to proceed. Let
me explain my requirement first.
I work as software developer in a business rules
s product software company. It bascically has a rule
engine which is used to evaluate certain input
conditions and return appropriate actions based on
those.This engine is already deployed as a
web-service and i can invoke it via axis server.
Now my task is to integrate this rule engine in
n OpenESB architecture.As I am going through the
specs and the demo ,i figured out few options:
1) the rule engine which is already deployed as a web
service can be called from outside the JBI
environment and used as an external service.
2)the rule engine can be installed as an internal
service to jbi environment.
is the second option viable?...actually it is
requirement not to use the axis server and that would
mean i cant use the present webservice engine.The second option should be viable. JBI was designed to give service engine (and binding component) implementors as much flexibility as possible. The fact that you already a working webservices interface to your rules engine suggests you've already done the hard work: finding a mapping from your component's application domain (business rules) to/from a services model.
Using the first option will still allow you do accomplish some interesting things with JBI. You could use the protocol hopping feature, for example, to allows JMS requests to be routed to the rules engine (via SOAP/HTTP). This does involve an extra protocol wire hop, but does expand your connectivity options beyond what Axis supports.
>
So,wat is the possibility of using my existing engine
classes inside JBI env. What exactly I would need to
do. And could you please suggest some document or
demo which can help me in this regard.
Implementing a JBI component can be quite simple, as long as the component itself is very simple. There are articles on the web concerning how this is done.
It sounds like you simply need to replace the I/O accomplished by the Axis SOAP stack with the JBI delivery channel. (Some adjustment may be necessarary to adapt to JBI's asynchronous message exchange model, but this is easily accomplished.)
You will need to adapt your engine to the JBI component life cycle model. This can be difficult, especially if it is controlled by other administrative tools. JBI assumes that the JBI MBeans have control of component life cycles (stop/start etc.). We've run into interesting situations controlling the life cycle of Servlet-based services, where the servlet container is a JBI service engine. The servlet container in question (in the Sun application server) already has a life cycle, which is controlled by the app server itself.
The most complex part of any JBI component tends to be the ServiceUnitManager implementation (which is optional). If you choose to implement this, you'll have to figure out how to dynamically add and remove rules (services) from your engine. If your engine supports dynamic changes to the rules deployed, you won't have any trouble. If your rules engine doesn't support this, then omit the ServiceUnitManager.
Any help in this regard will be highly appreciated.A good starting point is to download the NetBeans 5.5 beta; this includes a subset of Open ESB (called the starter kit), and a lot of tools integrated into the IDE to make creating composite applications for Open ESB easy to do. It will save you a lot of learning you'd otherwise need to invest in initially to learn how to use the administrative tools that come with Open ESB.
There are articles on the web concerning creation of JBI components. I believe some Sun people and Apache people have blogged about this as well. In addition, Open Source efforts like Open ESB include the source code for service engines. I suspect your rules engine would, in terms of message exchange patterns supported, be most similar to the Open ESB transformation engine. You might want to start there, copy the code, and alter it to suit your needs. (Of course, you'll need to conform to the CDDL terms if you do this, but it is a very "open" open-source license, akin to the Mozilla Public License.)
-Ron