1 2 3 Previous Next 33 Replies Latest reply on Feb 27, 2007 9:55 AM by Tom Baeyens

    various questions

    Tom Baeyens Master

      taking the liberty to post Fady's questions here so everyone can follow the conversation and join in.

      "Fady" wrote:
      Dear Tom,
      I have been reviewing the code of JBPM in CVS and the code of the
      web-console specifically.
      And I believe a number of enhancements need to take place.

      First of all, each workflow instance should be given a subject and a
      priority. Those fields can be hidden for some users. The benefits of
      them come when someone is dealing with a large number of tasks. The
      priority fields highlights the criticality of the task while the
      subject field provides with a quick way of identifying a task.

      Moreover, is there any extra documentation outside the repository? For
      instance I want to know what each JBPM tag is doing without having to
      go into the actual code. An architecture document if available would
      be very helpful.

      Waiting for your feedback,

      Best Regards,
      Fady


        • 1. Re: various questions
          Tom Baeyens Master

           

          "Fady" wrote:
          First of all, each workflow instance should be given a subject
          ...
          the
          subject field provides with a quick way of identifying a task.


          you mean as a variable ? what data should be filled in ? i don't think that it is a good idea to force the user to enter a subject. apart from that, the process definition contains a name and a description.

          also the task definition has a name that is copied into the task instance as a kind of default value. after that, the task instance name is changeable. don't know if the UI allows this currently, though.

          would the task instance name cover your requirements ? or how is your subject different ?

          "Fady" wrote:
          and a
          priority.
          ...
          The
          priority fields highlights the criticality of the task


          task definitions already have a priority. this priority is copied into a task instance when it is created. then the priority can be changed for that specific task instance. is that what you're looking for ?

          "Fady" wrote:

          Moreover, is there any extra documentation outside the repository? For
          instance I want to know what each JBPM tag is doing without having to
          go into the actual code. An architecture document if available would
          be very helpful.


          currently i'm the architecture document :-( feel free to use me for this purpose. maybe i should respond to all your questions in a wiki page so that can grow to become the architecture document...

          • 2. Re: various questions
            Fady Matar Novice

            Let's add the Wiki page to the JBPM web console wiki. Shall I create it?

            • 3. Re: various questions
              Tom Baeyens Master

              yes. good idea.

              • 4. Re: various questions
                Ronald van Kuijk Master

                Tom,

                The subject could be the 'business' key Gavin also wants for seam (at least that is how I interpret it)

                • 5. Re: various questions
                  Tom Baeyens Master

                   

                  "kukeltje" wrote:
                  Tom,

                  The subject could be the 'business' key Gavin also wants for seam (at least that is how I interpret it)


                  i don't want to impose users with the task of specifying a business key.

                  i think that hibernate or JPA should solve the object identity problem :-)

                  regards, tom.

                  • 6. Re: various questions
                    Edward Staub Expert

                    Hibernate/JPA can't solve the identity problem when the requirement is to apply a specific externally-generated identifier to the process and be able to reference the process by it later. This is a frequent business requirement.

                    In BPEL, all of the "Correlation Set" support addresses this - far more comprehensively than you/we perhaps have any need for.

                    -Ed Staub

                    • 7. Re: various questions
                      Ronald van Kuijk Master

                      I think that an externally generated businesskey on the process level, other than in a standard process variable, makes sense for jpdl as well, but that is my opinon. You should be able to pass it when starting a process.

                      • 8. Re: various questions
                        Tom Baeyens Master

                         

                        "estaub" wrote:
                        Hibernate/JPA can't solve the identity problem when the requirement is to apply a specific externally-generated identifier to the process and be able to reference the process by it later. This is a frequent business requirement.


                        IMO, HB/JPA could do a better job of supporting the object identity versus object equality problem.

                        "estaub" wrote:
                        In BPEL, all of the "Correlation Set" support addresses this - far more comprehensively than you/we perhaps have any need for.


                        correlation is related. but i don't see how this justifies the need for business keys. it could only show the opposite. namely that a single business key is not sufficient. to support correlation in bpel, we would need a set of correlations (set of set of primitive values) for each process instance.

                        regards, tom.

                        • 9. Re: various questions
                          Tom Baeyens Master

                           

                          "kukeltje" wrote:
                          I think that an externally generated businesskey on the process level, other than in a standard process variable, makes sense for jpdl as well, but that is my opinon. You should be able to pass it when starting a process.


                          i don't yet see the use cases.

                          first of all. technically, i think we could most easily implement a business key as a specially identified variable. (i don't think an extra join in the query is a big problem. even if that would be the case, it boils down to a performance issue and not a conceptual one)

                          second, while i can see the value of business keys for a number of use cases. making it mandatory is something else. i still see many use cases that would not require a business key. would they need to start inventing one ? that is still not clear to me. and just posing the invention of business key onto the user is unacceptable to me as i think this will increase the learning curve for a lot of people that don't need this feature.


                          • 10. Re: various questions
                            Edward Staub Expert

                            Tom,

                            You didn't have to put names on process definitions, nodes, etc., but you did. Why? - because people have external handles on these things (in these definition cases, mostly concepts in their brains) by which they want/need to refer to the definition elements.

                            In the process instance case, the "business key" frequently is some key value that also is externally held (either mentally or by another system) by which folks need to prioritize their tasks, monitor, or intervene in. Usually it refers to some variable that is the "subject" of the workflow. In my experience, folks nearly always want this in some form. If you are concerned about requiring folks to invent a key, you could defaullt it to a combination of definition and date/time.

                            I have a feeling there's some much deeper divergence in intent here... this is so obvious that it would have to be obvious to you unless we were starting from very different places. I don't know what the deeper difference is, though...

                            Thanks,
                            -Ed Staub

                            • 11. Re: various questions
                              David Lloyd Master

                              Why not do the same thing that has been done with names/descriptions - add a business key column for tokens/tasks/whatever, index it by default, but initialize it to null. This way if the user doesn't want to use it, they don't have to. I don't see it as a "mandatory or forbidden" kind of situation.

                              • 12. Re: various questions
                                Tom Baeyens Master

                                 

                                "estaub" wrote:
                                Tom,

                                You didn't have to put names on process definitions, nodes, etc., but you did. Why? - because people have external handles on these things (in these definition cases, mostly concepts in their brains) by which they want/need to refer to the definition elements.


                                i think i understand the concept.

                                but i have a hard time finding proper use cases for it. can you give examples ?

                                how would that differ from using the process variables ? just convenience methods ? or would it be conceptually difference.



                                • 13. Re: various questions
                                  Tom Baeyens Master

                                   

                                  "david.lloyd@jboss.com" wrote:
                                  Why not do the same thing that has been done with names/descriptions - add a business key column for tokens/tasks/whatever, index it by default, but initialize it to null. This way if the user doesn't want to use it, they don't have to. I don't see it as a "mandatory or forbidden" kind of situation.


                                  again, this would be equivalient to marking one variable as being special, right ?

                                  also here my main point is in finding the set of use cases that could guide me in finding the right methods that need to be implemented for this.

                                  regards, tom.

                                  • 14. Re: various questions
                                    David Lloyd Master

                                    Yes, that's exactly it - a specialized process variable. Having this sort of special process variable could be very handy in many cases - an account number, or request ID, or ticket number... for every use case I can think of, I can see how a business key would be useful. And by providing a common place for it, we can include it in the web console by default, and that's one less customization a user would have to do.

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