topic Re: There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ? in Alfresco Archive

There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ?

wendelkerr — Fri, 12 Jul 2013 20:14:06 GMT

I was trying to update the version of ProcessDefinition in the ProcessInstance and I found the class "SetProcessDefinitionVersionCmd", but it is necessary to call it from a commandExecutor. In my application, i use WELD and i can do the necessary cast for catch the commandExecutor. So i wonder, why

Re: There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ?

frederikherema1 — Wed, 17 Jul 2013 09:53:41 GMT

The SetProcessDefinitionVersionCmd (as the javadoc hints to) is to be used with great care and won't work for any process-definition you throw at it. Because this "process migration" is not feature-complete, we don't expose it in our API as we're not comfortable with "supporting" it as an API-feature.

However, since it's present in the codebase and tested, you can off course use it if you keep you're head with it. You can get a command-executor from the ProcessEngineConfigurationImpl (indeed a cast needed).

Re: There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ?

wendelkerr — Wed, 17 Jul 2013 14:49:03 GMT

Thanks for your reply Frederik !!

What do you think about we expose in the API, and explain in the javadoc that this method need to be used very carefully(I think it is explained already, but we can explain more) , and the every application is responsible for treat the exceptions thrown. Since everybody knows there are no miracle in change the version of process definitions.

Att,
Wendel Kerr

Re: There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ?

jbarrez — Wed, 17 Jul 2013 15:07:24 GMT

Experience has learned us that people don't read javadoc. That's why we don't expose it.

Re: There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ?

silvioneto — Wed, 17 Jul 2013 20:37:43 GMT

frederik, what do you mean by "'process migration'" is not feature-complete?

We realize that if we try to migrate an instance which its current task doesn't exist in the the destination process, the method will throw an Exception. But, what's the matter with it? The SetProcessDefinitionVersionCmd may let the instance somehow inconsistent?

I've just read the the Activiti In Action's section Dealing with process versioning and didn't realized how do you really deal with the limitation "that the already-running process instances will keep running against the existing version of the process definition." It's very common issue for us…

Re: There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ?

mikedias — Wed, 17 Jul 2013 21:06:19 GMT

Hi everyone!

And if the API method was called "tryUpdateProcessDefinition"? The volatile of method would be more clear!

Something like: "No miracles here" 🙂

Re: There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ?

frederikherema1 — Thu, 18 Jul 2013 08:00:12 GMT

LOL… Perhaps we an offer an easy way to execute a command trough the API, like: managementService.executeCommand(), however this opens up a lot of the internals and might not be such a good idea

Re: There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ?

mikedias — Fri, 19 Jul 2013 21:54:56 GMT

This is an option that solves the problem, but I think that is more dangerous that update process definition… @=

I don't know if a method with "try" in the name is a good idea, but your limitation becomes more clear!

As @silvioneto said, we don't understand why update process definition is so evil ]:-> … If the current activity exists in the new process definition, update. Otherwise, don't update. No miracles, right? This is OK for us. There is another situation that migration is a problem?

Re: There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ?

jbarrez — Wed, 24 Jul 2013 07:54:37 GMT

Well, if the activity maps one on one, it's easy.

However, it can easily go wrong. What if you have a user task. Now, in the next version this user task is part of a fork/join ie it is in parallel. Wehn you now simply use the method …. your process will be wrong, because you actually need to create an execution tree that maps to the new parallel behavior.

And this is only a very simple example, and as such it's a 'dangerous' thing

Re: There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ?

mikedias — Sat, 27 Jul 2013 22:58:03 GMT

Wow, you opened my eyes! With complex process, many situations can be problematic. *shok*

So, I agree with @frederick said. Execute a command via API is certainly a better option. Can we send a pull request with this?

PS: In the amazing activiti-neo4j, this will not be a problem!

Re: There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ?

mikedias — Sun, 28 Jul 2013 05:12:24 GMT

Pull request with <code>managementService.executeCommand()</code> was created: https://github.com/Activiti/Activiti/pull/103

Re: There are a motive for not exist a exposed API for 'SetProcessDefinitionVersionCmd' ?

frederikherema1 — Mon, 05 Aug 2013 07:41:49 GMT

Thanks for the pull-request. It has been merged by Joram last week.