Manage step return values

[ebousse]

Description

Until now, a GEMOC Studio execution engine was considering that executing a step would not produce any return value, even though some parts of the framework were expecting it to happen (eg. MSEOccurrence).

This PR fixes this, by requiring engines to support step return values, and by using said values correctly in the framework.

Changes

• Change AbstractExecutionEngine to transform:

protected void afterExecutionStep()

into

protected void afterExecutionStep(Optional<Object> returnValue)

Which means all execution engines will have to adapt to this change

• Change AbstractSequentialExecutionEngine to adapt to the above change

• Change AbstractCommandBasedSequentialExecutionEngine to adapt to the above change, which means changing this operation:

protected def void executeOperation(Object caller, Object[] parameters, String className, String operationName, Runnable operation)

into

protected def void executeOperation(Object caller, Object[] parameters, String className, String operationName, Callable<Optional<Object>> operation)

• (Bonus) Fix a bug that made step parameters added twice in a MSEOccurrence objet

Companion Pull Requests

• K3: Make StepCommand return Optionals diverse-project/k3#87
• ALE engine: Manage step return values and step parameters  gemoc-studio-execution-ale#57
• Java engine: Manage step return values gemoc-studio-execution-java#29
• MOCCML engine: Manage step return values gemoc-studio-execution-moccml#73