# hekailiang/squirrel

squirrel-foundation is a State Machine library, which provided a lightweight, easy use, type safe and programmable state machine implementation for Java.

Repository: https://github.com/hekailiang/squirrel
Canonical: https://ross.abutalabs.com/products/hekailiang-squirrel
Homepage: http://hekailiang.github.io/squirrel/
Language: Java
License: NOASSERTION
License Family: other
Topics: java, statemachine, state-machine, fsm, event-handlers
Last push: 2024-06-04T09:56:25+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:39:23.370411+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 4904, "days_push": 820, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2256, forks 537 (observed 2026-08-28T04:06:31.351566+00:00)

## What it is
squirrel-foundation is a lightweight, type-safe, and extensible finite state machine (FSM) library for Java. It lets developers declaratively define states, events, transitions, and actions with fluent builders and annotation-driven configuration.

## Use cases
- implement a state machine in java
- model atm or order lifecycle states
- build event-driven state transitions in enterprise java
- create a lightweight fsm library alternative for jvm
- handle state entry/exit actions and transition callbacks
- define type-safe state machines with fluent api

## When to choose
- you need a lightweight, embeddable state machine in a Java project
- you want type-safe, programmable FSM definitions with fluent builders
- you need diagnosable state machines with transition actions and listeners

## When to avoid
- you need a distributed workflow engine rather than an in-process FSM
- your project is not on the JVM
- you need a visual state chart designer or heavy orchestration features

## Facets
- artifact type: library
- maturity: maintenance
- function: state-management, workflow-automation, developer-tools
- domain: developer-tools
- platform: jvm
- tags: state-machine, fsm, finite-state-machine, event-driven, type-safe, algorithms, automation

## Member repositories
- hekailiang/squirrel (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:31.351566+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:43:42.511652+00:00, confidence not recorded.
  - readme: https://github.com/hekailiang/squirrel (fetched 2026-08-28T04:06:31.351566+00:00, sha 9ea728b8f5de)
  - homepage: http://hekailiang.github.io/squirrel/ (fetched 2026-08-29T10:23:33.401013+00:00, sha 4be8f3eb5b0d)
- Data as of 2026-08-30T08:39:29.467469+00:00.