After uml file is in place in your project, it can be imported into configuration using StateMachineModelConfigurer where StateMachineModelFactory is associated with a model. UmlStateMachineModelFactory is a special factory which knows how to process Eclipse Papyrus generated uml structure. Source uml file can either be given as a Spring Resource or a normal location string.

@Configuration
@EnableStateMachine
public static class Config1 extends StateMachineConfigurerAdapter<String, String> {

    @Override
    public void configure(StateMachineModelConfigurer<String, String> model) throws Exception {
        model
            .withModel()
                .factory(modelFactory());
    }

    @Bean
    public StateMachineModelFactory<String, String> modelFactory() {
        return new UmlStateMachineModelFactory("classpath:org/springframework/statemachine/uml/docs/simple-machine.uml");
    }
}

As usually Spring StateMachine is working with Guards and Actions which are defined as bean, those need to be hooked into uml by its internal modeling structure. In a below sections you will see how customized bean references are defined within uml definitions. Thought it is also possible to register particular methods manually without defining those as beans.

If UmlStateMachineModelFactory is created as a bean its ResourceLoader is wired automatically to find registered actions and guards. It’s also possible to manually define a StateMachineComponentResolver which will then be used to find these components. Factory also have methods registerAction and registerGuard which can be used to register these components.

Uml model is relatively loose what comes for the implementation like Spring StateMachine itself. There are choices what implementation need to take for uml support as it leaves a lot of features and functionalities for an implementation to decide. Below sections go through how Spring StateMachine will implement uml model based on Eclipse Papyrus plugin.

Let’s start by creating an empty state machine model.

You’ll start by creating a new model and giving it a name.

Then you need to choose a StateMachine Diagram.

You end up having an empty state machine.

In above sample named model you’ll end up three files, model.di, model.notation and model.uml which can then be used in any other eclipse instance and model.uml can be used by importing it into a Spring Statemachine.

State identifier is simply coming from a component name in a diagram. You must have initial state in your machine which is done by adding Initial and then drawing a transition to your own initial state.

In above we added one state S1, initial state, and draw a transition between those two to indicate that S1 is an initial state.

In above we added a second state S2 and added a transition between those two.

To associate an event for a transition you need to create a Signal E1. Done from RootElement→New Child→Signal.

And then SignalEvent with defined signal E1. Done from RootElement→New Child→SignalEvent.

Transition is simply created by drawing transition line between source and target states. In above we have states S1 and S2 and anonymous trasition between those two. We want to associate event E1 with that transition. We choose a transition, create a new trigger and define SignalEventE1 for that.

This will give you something like shown below.

	Tip
	If SignalEvent is omitted for a transition it becomes an anonymous transition.

Transition can also happen based on timed events. Spring Statemachine support two types of timers, ones which fires continously on a background and ones which fires once with a delay when state is entered.

Add new TimeEvent child to Model Explorer, modify When as expression defined as LiteralInteger. Value of it is then timer as milliseconds. Is Relative is left to false making timer to fire continously.

To define one timed based event when state is entered it’s exactly same as above but Is Relative is now defined as true.

Then what is left for user is to pick these time events instead of signal event for a particular transition.

State entry and exit actions can be associated by using a behaviour, more about this in Section 27.9, “Define Bean Reference”.

Guard can be defined by first adding Constraint and then defining its Specification as OpaqueExpression which works in a same way than Section 27.9, “Define Bean Reference”.

When there is a need to make a bean reference in any uml effect, action or guard, supported method to do that is via FunctionBehavior or OpaqueBehavior where defined language needs to be bean and language body having a bean reference id.

When there is a need to use a SpEL instead of a bean reference in any uml effect, action or guard, supported method to do that is via FunctionBehavior or OpaqueBehavior where defined language needs to be spel and language body having a SpEL expression.