Simple Final State Machine

Each instance of State Machine must be prepared with:

1. Initial state
2. Finish state - may be not several states
3. Intermediate states - optionally
4. All transitions needed

Each State may be specified with handlers:

1. Before handler - is called right before FSM changes INTO this state
2. After handler - is called right before FSM changes FROM this state to another
3. Processor - the method to process events

Transition is the Rule providing FSM the possibility to change between states.

Each transition must be determined in terms of:

1. From State - mandatory
2. To State - mandatory
3. Condition - optionally. If specified, the FSM will check the condition in order to check the possibility to change from FROM State into TO State

Example

Simple way to use it - to construct an inherited class specified with the type of events to be processed during transitions.

  SimpleFsm<String> simpleFsm = Fsm
    .<SimpleFsm<String>, String>from(SimpleFsm::new)
    .withStates()
      .from("init")
      .withBeforeHandler(fsm -> initBefore.set(true))
      .withAfterHandler(fsm -> initAfter.set(true))
      .withProcessor((fsm, event) -> initProcess.set(true))
    .end()
    .finish("finish")
      .withBeforeHandler(fsm -> finishBefore.set(true))
      .withAfterHandler(fsm -> finishAfter.set(true))
      .withProcessor((fsm, event) -> finishProcess.set(true))
    .end()
    .withTransition()
      .from("init")
      .to("finish")
      .checking((fsm, event) -> true)
    .end()
    .create();

or since 2.2.1

  SimpleFsm<String> simpleFsm = Fsm
    .<SimpleFsm<String>, String>from(SimpleFsm::new)
    .withStates()
      .from("init")
      .withBeforeHandler(fsm -> initBefore.set(true))
      .withAfterHandler(fsm -> initAfter.set(true))
      .withProcessor((fsm, event) -> initProcess.set(true))
      .withTransition()
        .to("finish")
        .checking((fsm, event) -> true)
      .endTransition()
    .end()
    .finish("finish")
      .withBeforeHandler(fsm -> finishBefore.set(true))
      .withAfterHandler(fsm -> finishAfter.set(true))
      .withProcessor((fsm, event) -> finishProcess.set(true))
    .end()
    .create();
  }

Releasing

Creating a new release involves the following steps:

1. ./mvnw gitflow:release-start gitflow:release-finish
2. git push origin master
3. git push --tags
4. git push origin develop

In order to deploy the release to Maven Central, you need to create an account at https://issues.sonatype.org and configure your account in ~/.m2/settings.xml:

<settings>
  <servers>
    <server>
      <id>ossrh</id>
      <username>your-jira-id</username>
      <password>your-jira-pwd</password>
    </server>
  </servers>
</settings>

The account also needs access to the project on Maven Central. This can be requested by another project member.

Then check out the release you want to deploy (git checkout x.y.z) and run ./mvnw deploy -Prelease.

Author

(c) bvn13