Fork and Join in spring state machine (Parallel execution) - spring

Question

I have an UML diagram as below :
How to configure states and transitions in state machine from SI to END based on events....
public class Config14
extends EnumStateMachineConfigurerAdapter<States, Events> {
#Override
public void configure(StateMachineStateConfigurer<States, Events> states)
throws Exception {
.....
}
#Override
public void configure(StateMachineTransitionConfigurer<States, Events> transitions)
throws Exception {
.....
}
}

Answer 1

Though it is late to answer, I will put my findings anyways.
To achieve the show state transitions, you need to have a fork/join pseudo states. As it has been mentioned over here (https://www.uml-diagrams.org/state-machine-diagrams.html), Pseudostates are typically used to connect multiple transitions into more complex state transitions paths. And their respective definition is as follows:
Fork pseudostate vertices serve to split an incoming transition into two or more transitions terminating on orthogonal target vertices (i.e., vertices in different regions of a composite state).
Join pseudostate merges several transitions originating from source vertices in different orthogonal regions.
One should note that segments outgoing from a fork vertex must not have guards or triggers(same applies for a Join).
Your config should more or less be like the following:
#Override
public void configure(StateMachineStateConfigurer<String, String> states) throws Exception {
states
.withStates()
.initial("SI")
.fork("S1")
.join("JOIN")
.state("S11")
.state("S12")
.state("S2")
.end("END")
.and()
.withStates()
.parent("S1")
.initial("S11")
.end("S11") //not very sure about this
.and()
.withStates()
.parent("S1")
.initial("S12")
.end("S12");
}
and
#Override
public void configure(StateMachineTransitionConfigurer<String, String> transitions) throws Exception {
transitions.withExternal()
.source("SI").target("S1").event("YOUR_EVENT")
.and()
.withExternal()
.source("S2").target("END").event("YOUR_EVENT")
.and()
.withFork()
.source("S1")
.target("S11")
.target("S12")
.and()
.withJoin()
.source("S11")
.source("S12")
.target("JOIN");
}
For a sample, check https://github.com/amenski/statemachine