User Story (Required on creation):

As a user, in modeling resources (e.g., on sequence flows), I can define expressions that call methods on a bean.

Functional Requirements (Required before implementation):

E.g., in a sequence flow camunda:expression attribute, I can use the following expression:
${myService.checkCondition('foo')}

Technical Requirements (Required before implementation):

Quarkus ArC does not support the API method BeanManager#getELResolver. Replace it with something else.

Limitations of Scope (Optional):

Hints (Optional):

Right now, only a simple JUEL expression referencing a delegate bean directly can be resolved: ${myDelegateBean}. Referencing a delegate bean via a more complex expression is not possible ${myBean.getDelegateBean()} due to missing support in Quarkus ArC of BeanManager#getELResolver. Let's evaluate if and how we can fix this.

Solution ideas

1. Shade de.odysseus.juel into the Quarkus extension like we already do it in the legacy JUEL FEEL Engine.
   • Or even cleaner: create a shaded jar containing de.odysseus.juel the DMN legacy FEEL Engine, as well as Quarkus, uses.
   • Identify Quarkus environment by catching the UnsupportedOperationException when BeanManager#getELResolver is called in CdiResolver#getWrappedResolver.
   • Register the javax.el.BeanELResolver instead.
     • Tries to create a ExpressionFactory by looking up the SPI.
   • Register an ExpressionFactory SPI in the Qurkus extension pointing to de.odysseus.el.ExpressionFactoryImpl.
   • See prototypical implementation (shading is missing): fix-quarkus-el-support.patch.txt
2. Wait until Quarkus supports BeanManager#getELResolver