Extend Queries for e.g. CaseInstance

Flowable Engine
1

Hello everyone,
I would like to be able to filter for unassigned cases (cases without any identylink of type ASSIGNEE). I can relatively easily do that on the database by using a where not exists(select 1 from ACT_RU_IDENTITYLINK … ) clause. However I see no easy way how to hook that into flowable such that I can still use the CmmnRuntimeService and its configuration.
Am I missing something? What would be a reasonable way of writing such an extension? I expect this will not be the last time that I would like to query something outside of what the predefine mybatis queries support.
Would I have to open PRs in github for them? What if they are not very generally useful and rather specific for my usecase?

Of course I could read all cases and filter in memory but that sounds like a very unreasonable thing to do performance and resource wise.

Thanks in advance
Philippe

2

Hi,

use custom sql query.

Examples for tasks, but can be used in the same way for cases:

Regards

Martin

3

The best work around would be to set a case variable "“owner” when owner is assigned. You can then use something like:
cmmnRuntimeService.createCaseInstanceQuery()
.variableNotExists(“owner”)
.list();

Cheers,
Greg

4

Thanks for the suggestion @gdharley, that sounds like a reasonable workaround, I’ll try that (and will mark the question as solved if I get it working).
I’ll probably also open a PR to allow native queries for cases, I don’t see why that would not work for cases but does work for most other things… thanks for the pointer @martin.grofcik

Cheers
Philippe

5

Hey @cdm-phm,

For things like this it would indeed be best to open PRs. Not sure what you have in mind, but some things could be done in a more generic way that would cover different usecases, similar like the variable query options and / or similar to what we have for the task queries.
e.g.

CaseInstanceQuery unassigned();

CaseInstanceQuery assigned();

CaseInstanceQuery withoutIdentityLinkType(String identityLinkType);

CaseInstanceQuery withIdentityLinkType(String identityLinkType);

For something more specific we already have something like

CaseInstanceQuery involvedUser(String userId, String identityLinkType);
    
CaseInstanceQuery involvedGroup(String groupId, String identityLinkType);

Cheers,
Filip

6

Hi @filiphr,

the withoutIdentityLinkType() is actually exactly what I had implemented :slight_smile:
Still, seeing that pretty much anything besides Case supports a selectXByNativeQuery I’d say it makes sense to add that one as well. I’ll try to find time to open an issue and a PR.