topic Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition in Alfresco Forum

Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ksgphellow — Thu, 22 Feb 2018 11:09:25 GMT

Hello there,Is there a possibility in Activiti to define certain Process Variables as Required in a Process Definition and request a list of those required variables from a Process Definition?The Reason I'm asking is, I want to make some sort of Process Repository for Process selection.Since my Proc

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ryandawson — Thu, 22 Feb 2018 12:00:01 GMT

Sounds like a use-case for start-forms with the forms set to have some required properties - I'd suggest to have a look at Activiti User Guide and see if it's a fit

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ksgphellow — Thu, 22 Feb 2018 16:10:31 GMT

I'd agree with you, but I have, and need to have my own Implementation of forms and not in java, so I cant really use those.

Thanks for the Idea though.

Are there any other possibilities ?

The main thing I need, is to just define required process variables and prompt them when looking up what process definitions I have in my repository.

Thanks in advance

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ryandawson — Fri, 23 Feb 2018 09:01:48 GMT

Basically you want to store a list of the required process variables against each process definition. If that information will be in your forms then maybe you can find a way to get access to it from java or have the forms and the java get it from a common source. If it won't be in the forms or you can't get it then I guess basically you just need to capture it in a way the java can get it. If you've only a small amount of data then maybe you could put it in a properties file and check against it before you make the call to start a process. If it's more data then maybe a database table. I can't think of an Activiti-native way of doing this - probably because the Activiti way would be Activiti forms (but it's possible there is one and I'm missing it).

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ksgphellow — Fri, 23 Feb 2018 09:06:53 GMT

Okay thanks,

I'll think of something.

Shame that Activiti Process Definitions cant be prompted for something like that. Would be a really nice feature.

Thanks again for your help.

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

Anonymous — Fri, 23 Feb 2018 09:26:26 GMT

How about Data objects too?

https://www.activiti.org/userguide/#dataobjects

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ksgphellow — Fri, 23 Feb 2018 09:31:20 GMT

Those look promising, question is though, can these be prompted? Via the Repositry Service for example? I.e can I look these up somehow? Didnt find anything in the userguide regarding that.

Thanks

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ryandawson — Fri, 23 Feb 2018 09:32:15 GMT

The main reason I don't think it's there is because Activiti/VariableInstance.xml at develop · Activiti/Activiti · GitHub doesn't feature any 'required' column/attribute. You should be able to find out which are the variables for the process definition in advance of starting it (Activiti/ProcessDefinitionEntityImpl.java at develop · Activiti/Activiti · GitHub ) by querying through repositoryService.createProcessDefinitionQuery. Without the 'required' attribute you won't have everything you want.

A hack might be to use some naming convention to capture which variables are required and which not.

We'd be open to discussing contributions (for which gitter.im/Activiti/Activiti7 is the best place). I can see the value in having that as an information-only field. I doubt we'd want the engine to enforce which variables are required or not as I think we'd want to leave that to the process implementation but we could talk more about that if you like.

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ksgphellow — Fri, 23 Feb 2018 09:35:06 GMT

Okay, thanks for the Input, both of you.

I'll try around with what Information you've given me and see if that gets me where I want to be 😃

Thanks again for your help.

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

Anonymous — Fri, 23 Feb 2018 09:50:59 GMT

List<ValuedDataObject> dataObjects = repositoryService.getBpmnModel("processDefinitionId").getProcessById("processDefinitionKey").getDataObjects();
for(ValuedDataObject dataObject: dataObjects){
System.out.println(dataObject.getId());
System.out.println(dataObject.getName());
System.out.println(dataObject.getType());
}

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ryandawson — Fri, 23 Feb 2018 10:49:34 GMT

Actually I looked further and found there are no calls to the getter or setter of variables on ProcessDefinitionEntityImpl in the engine. I thought that if the variables were defined in the process definition xml then they would at least be linked to the process definition entity but now I'm thinking not. The most relevant-looking tests actually just go through the runtimeService to get variables from the running instance after starting (Activiti/VariableScopeTest.java at develop · Activiti/Activiti · GitHub with XML at Activiti/activiti-engine/src/test/resources/org/activiti/engine/test/db at develop · Activiti/Activiti · GitHub ). My impression is that this is a gap.

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ksgphellow — Sat, 24 Feb 2018 15:10:30 GMT

I've also done a bit of code research and would like to make sure I havent missed anything.

Am I correct in that there is currently no way to get / lookup Process Variables of a ProcessDefinition? (Weither required or not is not important at this time).

Is so, I guess I'll have to find a way to make a database for holding these in parallel to the deployed processDefinitions.

Thanks for your input.

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

Anonymous — Sun, 25 Feb 2018 08:12:04 GMT

If your goal is only to define a list of variables used in the process in the process, I think that Data objects is optimal.
https://www.activiti.org/userguide/#dataobjects

And, you can get that list by the following code.

List<ValuedDataObject> dataObjects = repositoryService.getBpmnModel("processDefinitionId").getProcessById("processDefinitionKey").getDataObjects();
for(ValuedDataObject dataObject: dataObjects){
  System.out.println(dataObject.getId());
  System.out.println(dataObject.getName());
  System.out.println(dataObject.getType());
}   ad

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ksgphellow — Sun, 25 Feb 2018 08:36:52 GMT

Ah thanks, tried around a bit with those, hadnt had the idea to get them via the bpmn model.

Yeah getting that far is atleast a good first step for my usecase, I'll be able to build up on top of that.

Thanks alot for your help.

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ksgphellow — Tue, 27 Feb 2018 09:52:27 GMT

Might be a stupid Question, but: Am I correct in that the DataObjects can only be defined programmatically or in the xml file ? and not in the Activiti Editor?

Thanks

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

Anonymous — Tue, 27 Feb 2018 10:03:06 GMT

All you can use.

programmatically
xml file
Activiti Editor/Activiti Designer

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ksgphellow — Tue, 27 Feb 2018 10:20:46 GMT

Hm okay, didnt find it in the editor, strange. Okay I'll have a look again.

Thank you.

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

Anonymous — Tue, 27 Feb 2018 10:40:49 GMT

I'm sorry that Data Object setting diappear from Activiti Editor...

Re: Define Required Process Variables and Get Information on those before instantiating a ProcessDefinition

ksgphellow — Tue, 27 Feb 2018 10:42:37 GMT

Ok, thanks for the info, no worries.

I'll just define the data objects in xml.

Thanks again.