-
Sub-task
-
Resolution: Unresolved
-
L3 - Default
-
None
-
None
-
None
AT
- In Scala DMN, Script Engines can use process engine context
- Document breaking changes in migration guide (e.g., when removing interfaces)
Reasoning
- When using JUEL in the legacy DMN Engine, context providers registered in the process engine can be used (optionally via Spring & CDI)
- Context switch in Process Applications is performed
- Beans can be resolved
- By default built-in function mappers are available (this is not the case for Spring & CDI)
- Providing the process engine context with JUEL in the Scala DMN Engine makes migrating from the legacy DMN Engine smooth
- Since FEEL ist the expression language designed for DMN it makes sense to provide process engine context in FEEL and not only for JUEL
- With respect to the high adoption of the Spring Boot Starter it makes sense to provide registered beans in FEEL/JUEL
Status Quo JUEL
- In process engine config ExpressionManager is initialized in initExpressionManager (Spring and CDI have dedicated expression managers)
- Functions mappers are registered (e.g., currentUser, now, etc.) => not in Spring & CDI
- ExpressionManager is wrapped in ProcessEngineElProvider (implements ElProvider)
- ProcessEngineElProvider is registered in Legacy DMN Engine
Status Quo Script Engines
Script engines that can be used in the legacy DMN Engine can be registered in...
-
- the Process Engine via ScriptEngineResolver#addScriptEngineFactory
- a Process Application (via SPI & via ScriptEngineResolver#addScriptEngineFactory)
- a SPI and be resolved via ScriptEngineManager
Solution Ideas
Process Engine context can be used in ...
- ... FEEL
- ... JUEL (previous behavior)
- ... all registered Script Engines
Scope
- Minimum: use context either in JUEL or FEEL
- Adding JUEL support is probably easier
- Medium: JUEL and FEEL
- JUEL due to backward compatibility
- FEEL because it is the default expression language in DMN
- Maximum: context can be used In all possible expression languages
See
This ticket was migrated to github: https://github.com/camunda/camunda-bpm-platform/issues/2538. Please use this link for any future references and continue any discussion there.