akka/akka-core

PersistentFSMActor: Remove duplication between akka.actor.FSM and akka.persistence.fsm.FSM

Open

#18,154 opened on Aug 9, 2015

View on GitHub
 (0 comments) (0 reactions) (0 assignees)Scala (13,277 stars) (3,547 forks)batch import
1 - triagedhelp wantedt:persistence

Description

Currently akka.persistence.fsm.PersistentFSMActor inherits from akka.persistence.fsm.FSM - a clone of the original akka.actor.FSM with some Event Sourcing related changes in FSM's DSL. Possible ways to fix this: akka.persistence.fsm.FSM should either be derived from the original FSM or a common trait should be introduced - for example:

trait FSMCore {...}
trait FSM extends FSMCore {...}
trait EventSourcedFSM extends FSMCore {...}

Contributor guide

Tech stack
scala
Domain
backend
Issue type
refactor
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Scala programmingAkka framework basicsUnderstanding of FSM pattern
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the current code in akka.persistence.fsm.FSM and akka.actor.FSM. The goal is to create an intermediate trait (e.g., FSMCore) that contains common logic, and then have both FSM and EventSourcedFSM extend it. Focus on the duplication between the two FSM implementations and ensure backward compatibility. The proposed solution is outlined in the issue: extract a common FSMCore trait. Look at the existing API and internal methods to identify shared functionality.