[jbpm-dev] Human-Task module problematic..

Brad Davis brad.davis at amentra.com
Thu Oct 20 08:21:11 EDT 2011 

I think we should offer human task service as part of the bpm, but agree it should be a war to deploy along with the bpm.

Bpm is more than just an embeded process library these days. Competition will offer bam, task services, and form management in their toolsets, and we should too.

I am for using apache cxf for the task service. That way we can expose it as soap, soap over jms, or any of the other endpoint adapters with little more than configuration.

Brad



On Oct 20, 2011, at 8:17 AM, "Marco Rietveld" <mrietvel at redhat.com<mailto:mrietvel at redhat.com>> wrote:

Mauricio,

Why don't you think that the module should be a web application?

And why do you want to put the code that implements the server, client and async. nature in the jBPM project??

Thanks,
Marco

10/20/2011 02:09 PM, Mauricio Salatino:
Hi marco,
We have implemented a project that basically provides the bindings for the current module with the WS Interface proposed by WS-HT standard. Doing that we have introduced a lot of boilerplate with the data types proposed in the standard. If you take a look at the new interface that is called TaskService you will see that thats the synchronous interface with the methods that we can expose with WS or JMS(Commands like in drools), but I don't believe that the module should be a Web application. If you talk with kris about this you will find that I have a couple of pending task related with hooking up the task service to the JNDI tree to be able to be used by multiple applications for example in tomcat or jboss.

I'm open to create a project in my github account where we can play around and coordinate that effort, I also have access to a jenkings server to keep it blue. The main problem with the module human task module is that is being used and we cannot break it or change it completely.

-> https://github.com/Salaboy/human-tasks-playground

I've already added you Marco as a collaborator..
I think that the main idea will be to build a proposal to see what we can do and how we can handle the existing users.
Marco what do you think about that? what are the main goals that you want to achieve?
If someone else is interested in this idea please write us back.

Cheers

On Thu, Oct 20, 2011 at 8:58 AM, Marco Rietveld <mrietvel at redhat.com<mailto:mrietvel at redhat.com>> wrote:

Mauricio,

You know the code better than I do, but IMO, the infrastructure code in that module is not okay.

> I really like the idea of having this human task module completely decoupled from the rest of the project

I am all for this. Would you mind hosting it on your github, then?


A lot of the jBPM related code seems to be okay, it's mostly how the module is set up that bothers me.

It seems like it would be a better idea to implement the human-task as a webservice war. That way, we could get rid of the server, client and asynchronous code in the module and concentrate on the jBPM stuff. The JAX-WS standard includes asynchronous webservices, and webservices can be coupled to JMS implementations as well.

For more information on JAX WS asynchronous services, please see the following links:

 *   http://today.java.net/pub/a/today/2006/09/19/asynchronous-jax-ws-web-services.html#asynchronous-computation-with-future-and-callback
 *   http://publib.boulder.ibm.com/infocenter/wasinfo/v7r0/index.jsp?topic=%2Fcom.ibm.websphere.express.doc%2Finfo%2Fexp%2Fae%2Ftwbs_jaxwsclientasync.html
 *   http://biemond.blogspot.com/2011/02/building-asynchronous-web-service-with.html
    *   (not especially about async services, but gives you an idea of what the code looks like)

Thanks,
Marco

10/20/2011 01:27 PM, Mauricio Salatino:
Hi Marco,
My opinion about it is good, I mean, we need to improve the transport layer of it, but the rest of the code is ok. If you take a look at one of my last pull requests, it was related with the fact that we need a synchronous interface to simplify all the interactions and to hide all the boilerplate of async communications.

If you want to simply things to start having more smaller and controlled pieces I suggest you to take a look at this other pull request: https://github.com/droolsjbpm/jbpm/pull/28
Which aims to split the logic that we currently have inside the human task module into several modules with their own dependencies. That will allow us to do internal changes, api changes as well as transport changes in a more manageable way.

I really like the idea of having this human task module completely decoupled from the rest of the project and I'm willing to help as much as I can to improve it because I found that not only jBPM can leverage the power of it.

Let's keep this discussion open so we can gather more requirements from the people that is using it.

Cheers

On Thu, Oct 20, 2011 at 7:19 AM, Marco Rietveld <mrietvel at redhat.com<mailto:mrietvel at redhat.com>> wrote:
Hi guys,

Having looked through the architecture of the Human-Task module in the last month or so, I've become fairly pessimistic about it.


The biggest problem I'm seeing is that the "wheel is reinvented" a couple times -- and the "reinvented wheels" that are present in the Human-Task service will be a pain to maintain/troubleshoot.

The "reinvented wheels" are things like the following:

 1.  The server logic
    *   BaseJMSTaskServer, TaskServerHandler, etc.
 2.  The client logic
    *   TaskClientHandler, the ResponseHandler and all it's children classes)
 3.  The asynchronous/concurrency logic
    *   AbstractBlockingResponseHandler{.waitTillDone(long) } and every class that uses that method (and every class that uses the class that uses that method.. etc.)


 I think my frustration with this can best be expressed by the fact that jBPM is a process engine project -- it's not a server project, it's not a (service) client project, and it certainly isn't a project that supports asynchronous communication. And yet, we're implementing all 3 in the module. :/


Lastly, the human-task module code is the reason that the jbpm builds (on hudson.jboss.org<http://hudson.jboss.org>) have been failing for the last month or so. And the tests are not failing because the tests are wrong: the tests are failing because there's a race condition in the code, and it occurs when you run the human-task code on a 1. heavily loaded server that's experiencing 2. lots of network traffic. Which is what the hudson.jboss.org<http://hudson.jboss.org> is.


I guess I'm wondering what other people's opinions about this are!


Thanks,
Marco


--
jBPM/Drools developer
Utrecht, the Netherlands

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--
 - CTO @ http://www.plugtree.com
 - MyJourney @ http://salaboy.wordpress.com
- Co-Founder @ http://www.jugargentina.org
 - Co-Founder @ http://www.jbug.com.ar

 - Salatino "Salaboy" Mauricio -




--
jBPM/Drools developer
Utrecht, the Netherlands



--
 - CTO @ http://www.plugtree.com
 - MyJourney @ http://salaboy.wordpress.com
- Co-Founder @ http://www.jugargentina.org
 - Co-Founder @ http://www.jbug.com.ar

 - Salatino "Salaboy" Mauricio -




--
jBPM/Drools developer
Utrecht, the Netherlands

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