Export

Page contents

• PlantUML
• Mermaid
• Controlling export output

The library supports export into PlantUML and Mermaid diagram drawing systems. They both use PlantUML text format. Mermaid supports fewer features then PlantUML itself. Please note that both of them have their own limitations and corner cases.

Transitions that use lambdas like transitionConditionally() and transitionOn() or choiceState() etc., are not exported by default. You can enable their export with unsafeCallConditionalLambdas flag of exportToPlantUml()/exportToMermaid() functions. With unsafeCallConditionalLambdas flag set, user defined lambdas that are passed to the library to calculate next state would be called during export process. This will give more complete (still not full) export output, but may cause runtime errors depending on what the lambda actually do. As it may touch application data that is not valid when export is running, also event argument will be faked by unsafe cast, so touching it will cause ClassCastException That is why unsafeCallConditionalLambdas flag should be considered as debug/development tool only.

PlantUML

Use exportToPlantUml()/exportToPlantUmlBlocking() extension function to export state machine to PlantUML state diagram. showEventLabels flag allows to include Event types into the output.

val machine = createStateMachine(scope) { /* ... */ }
println(machine.exportToPlantUml())

Copy/paste resulting output to Plant UML online editor

See PlantUML nested states export sample

Mermaid

Mermaid uses almost the same text format as PlantUML for compatibility reasons.

Use exportToMermaid()/exportToToMermaidBlocking() extension function to export state machine to Mermaid state diagram. showEventLabels flag allows to include Event types into the output.

val machine = createStateMachine(scope) { /* ... */ }
println(machine.exportToMermaid())

• Intellij IDEA users may use official Mermaid plugin to view diagrams directly in IDE for file types: .mmd and .mermaid.
• or copy/paste resulting output to Mermaid live editor

See Mermaid nested states export sample

Controlling export output

To beautify and enrich export output, you can use UmlMetaInfo for both IState and Transition. It can be built with buildUmlMetaInfo() function:

state("State1") {
    metaInfo = buildUmlMetaInfo {
        umlLabel = "State 1 long label"
        umlStateDescriptions = listOf("Description 1", "Description 2")
        umlNotes = listOf("Note 1", "Note 2")
    }
}

See PlantUML with MetaInfo export sample