topic Re: Start process synchronously and return results Back in Alfresco Archive

Start process synchronously and return results Back

smirzai — Wed, 17 Jul 2013 09:49:17 GMT

Actually this is a continuation of this topic: http://forums.activiti.org/content/starting-process-instance-synchronouslyEspecially in OLTP or embeded use cases, one wants to run the workflow and get the results synchronously. In some cases there is no real database behind or the performance requi

Re: Start process synchronously and return results Back

smirzai — Wed, 17 Jul 2013 09:53:17 GMT

ok, actually the name of the function should be something else, say

<code>
Map outcome = runtimeService.startInstanceSync("myProcess", vars);
</code>

Re: Start process synchronously and return results Back

mdaviot — Wed, 17 Jul 2013 10:25:46 GMT

1st idea :
Looks great, fits exactly with what I had in mind. We could then enhance the designer UI to map these output variables like it is done in call activity mapping.

2nd idea :
Maybe an even simpler approach would be to always return in the map all variables in scope at the end of the process, so you don't even need to define the mapping, just to add these startInstanceSync methods in the API.

Honestly I’m not sure it really adds that much value to specify which variables are published at the end of the process so I would recommend the 2nd idea.

Re: Start process synchronously and return results Back

frederikherema1 — Wed, 17 Jul 2013 12:44:16 GMT

I understand where you're coming from. Processes without wait-state won't be in the runtime-tables because, at the end of the API-call, all entities are deleted. only history is left behind. However, there is more to a process than just it's variables (path it went trough, for example) so I'm not sure it's as simple as just returning a map of variables (also, what with sub-execution-variables and name-clashes).

Currently, you can use a process-end listener (and potentially the BPMNParseHandler approach to add listeners to any process to keep BPMN xml unaware of spacial handling) that saves the process-variables etc. to a thead-local map. After you have called the startProcessByXXX() you access the map and have a blast

Re: Start process synchronously and return results Back

smirzai — Wed, 17 Jul 2013 14:00:32 GMT

Something like that is the idea for implementation. But don't you think adding the support to the engine itself, instead of configuring it each time, might be a useful extension for Activiti ?

Re: Start process synchronously and return results Back

frederikherema1 — Wed, 17 Jul 2013 14:28:36 GMT

Yes, it would be a useful extension if the result you get back is actually complete (not just the variables). This should be thought trough if we want to add it to the engine. ATM, we don't have the bandwidth ourselves to add this feature, but I'm happy the review/discuss any suggestions/implementations around this.

Re: Start process synchronously and return results Back

jbarrez — Tue, 23 Jul 2013 09:22:34 GMT

I'm not convinced we should add this feature.

If your process is 100% synchronous, simply pass an object in the variables map, and populate the object values during process execution.
When your process finished, the object will now have all the values set. This already works now and doesn't need any new implementation work.

Re: Start process synchronously and return results Back

smirzai — Fri, 23 Aug 2013 12:26:16 GMT

@jbarrez: even if the process is not itslef 100% synchronous, one may want to call it synchronously and wait until all the paths are completed.

Re: Start process synchronously and return results Back

smirzai — Fri, 23 Aug 2013 16:28:38 GMT

This is the exact same request:
http://forums.activiti.org/content/out-variables-primary-process-proposal

Re: Start process synchronously and return results Back

jbarrez — Tue, 03 Sep 2013 09:41:11 GMT

I'm just afraid of adding thread waiting to a call. It is a potential performance bottleneck of major implications.
Activiti has never interfered with client threads so far, and I'd like to keep it that way, it keeps things simple and understandable.

If you really need it, it's very easy to do yourself with thread waiting and polling the service.

Re: Start process synchronously and return results Back

fnoorie — Mon, 27 Apr 2015 16:28:29 GMT

@Joram

Referring to your answer above:

"If your process is 100% synchronous, simply pass an object in the variables map, and populate the object values during process execution.
When your process finished, the object will now have all the values set. This already works now and doesn't need any new implementation work."

My process is as follows:

<code>
Map<String, Object> variables = new HashMap<String, Object>();
        variables.put("accountNumber", accountNumber);
        variables.put("errorFlow", false);
        variables.put("respObject", null);
        variables.put("respStatus", null);
        RuntimeService runtimeService = processEngine.getRuntimeService();
        ProcessInstance processInstance = runtimeService.startProcessInstanceByKey("GetAccountPriceCategory", variables);
</code>

In one of the tasks I set the following:
<code>
execution.setVariable("respObject", accountPriceCategory);
execution.setVariable("respStatus", Status.OK);
</code>

But when the process finishes respObject and respStatus are null.

Re: Start process synchronously and return results Back

jbarrez — Tue, 28 Apr 2015 18:56:41 GMT

No, the respObject would need to be a real object, with a member field for the stuff you want to store.

Re: Start process synchronously and return results Back

jubedus — Wed, 27 Jan 2016 15:52:27 GMT

Hi Joram,

Could you please post an example of using a real object for returning values from a workflow? I haven't been able to implement it with Activiti 5.19.0. Thanks a lot in advance!

Re: Start process synchronously and return results Back

jbarrez — Mon, 01 Feb 2016 08:52:24 GMT

You simply create a Pojo, with some member fields. You pass it when doing startProcessInstanceByKey(key, variables) in the variables map. When the process is straight through, all the changes that have been done in the process to the pojo will be in the actual pojo (as no copy has been made … this only works for a straight through process!)

Re: Start process synchronously and return results Back

gourahari_activ — Fri, 03 Jun 2016 06:54:33 GMT

Hi jbarrez,
I am new to Acititvi BPM. I read lots of post ,books,forums.
Could you please explain with simple example , How an html form will call "start Event" . I mean to say how external third party UI will call BPM and controll the all activiti.

Actitviti User guide doed not help me . I am using ACTVITI-5x

If you will explain me ,it will great help.

Thanks in advance.

Re: Start process synchronously and return results Back

gourahari_activ — Fri, 03 Jun 2016 06:55:11 GMT

Re: Start process synchronously and return results Back

jbarrez — Fri, 03 Jun 2016 08:23:03 GMT

I responded to your duplicate of this post somewhere else.

Re: Start process synchronously and return results Back

chary — Wed, 24 Aug 2016 13:02:49 GMT

Below is the sample code:
***********

Map<String, Object> map = new HashMap<String, Object>();
map.put("appId", appId);
map.put("appName", appName);

/* to catch workflow execution result */
map.put("regResult", new AppRegistrationResult());

ProcessInstance process = this.processEngine.getRuntimeService()
.startProcessInstanceByKey("AppRegistrationProcess", map);

/* extract the result */
AppRegistrationResult registrationResult = map.get("regResult");