kotlin

state_machines/kotlin_simple_state_machine/build.gradle.kts

@@ -0,0 +1,17 @@
+plugins {
+    kotlin("jvm") version "1.9.22"
+    id("org.springframework.boot") version "3.2.3"
+    id("io.spring.dependency-management") version "1.1.4"
+}
+
+group = "click.kamil"
+version = "1.0-SNAPSHOT"
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation("org.springframework.statemachine:spring-statemachine-core:3.2.1")
+    implementation("org.jetbrains.kotlin:kotlin-reflect")
+}

state_machines/kotlin_simple_state_machine/src/main/kotlin/click/kamil/OrderStateMachine.kt

@@ -0,0 +1,37 @@
+package click.kamil
+
+import org.springframework.statemachine.config.EnableStateMachine
+import org.springframework.statemachine.config.EnumStateMachineConfigurerAdapter
+import org.springframework.statemachine.config.builders.StateMachineStateConfigurer
+import org.springframework.statemachine.config.builders.StateMachineTransitionConfigurer
+
+enum class OrderState { NEW, PROCESSING, SHIPPED, COMPLETED }
+enum class OrderEvent { PAY, SHIP, DELIVER }
+
+@EnableStateMachine
+class OrderStateMachine : EnumStateMachineConfigurerAdapter<OrderState, OrderEvent>() {
+
+    override fun configure(states: StateMachineStateConfigurer<OrderState, OrderEvent>) {
+        states
+            .withStates()
+            .initial(OrderState.NEW)
+            .states(setOf(OrderState.NEW, OrderState.PROCESSING, OrderState.SHIPPED, OrderState.COMPLETED))
+    }
+
+    override fun configure(transitions: StateMachineTransitionConfigurer<OrderState, OrderEvent>) {
+        transitions
+            .withExternal()
+                .source(OrderState.NEW).target(OrderState.PROCESSING)
+                .event(OrderEvent.PAY)
+                .action { println("Payment received") }
+            .and()
+            .withExternal()
+                .source(OrderState.PROCESSING).target(OrderState.SHIPPED)
+                .event(OrderEvent.SHIP)
+                .guard { true }
+            .and()
+            .withExternal()
+                .source(OrderState.SHIPPED).target(OrderState.COMPLETED)
+                .event(OrderEvent.DELIVER)
+    }
+}