transition enricher rabbit

state_machines/complex_multi_module_sm/domain/src/main/java/click/kamil/domain/CustomStateMachineMessage.java

@@ -0,0 +1,24 @@
+package click.kamil.domain;
+
+import org.springframework.messaging.support.GenericMessage;
+
+import java.util.Map;
+
+public class CustomStateMachineMessage<T, P> extends GenericMessage<T> {
+
+    private final P customPayload;
+
+    public CustomStateMachineMessage(T payload, P customPayload) {
+        super(payload);
+        this.customPayload = customPayload;
+    }
+
+    public CustomStateMachineMessage(T payload, Map<String, Object> headers, P customPayload) {
+        super(payload, headers);
+        this.customPayload = customPayload;
+    }
+
+    public P getCustomPayload() {
+        return customPayload;
+    }
+}

state_machines/complex_multi_module_sm/service/src/main/java/click/kamil/service/StateMachineService.java

@@ -14,6 +14,9 @@ public interface StateMachineService {
     // Quirky pattern 2: Generic Varargs
     <T extends IEvent> void sendEventsVarargs(T... events);
 
+    // Child class of Spring's GenericMessage with a generic payload
+    <T extends click.kamil.domain.OrderEvent, P> void sendCustomMessage(click.kamil.domain.CustomStateMachineMessage<T, P> customMessage);
+
     // Quirky pattern 3: Multiple generic bounds (Intersection Types)
     <T extends IEvent & java.io.Serializable & Cloneable> T processQuirkyEvent(T event);
 }

state_machines/complex_multi_module_sm/service/src/main/java/click/kamil/service/StateMachineServiceImpl.java

@@ -54,12 +54,21 @@ public class StateMachineServiceImpl implements StateMachineService {
     @Override
     @SafeVarargs
     public final <T extends IEvent> void sendEventsVarargs(T... events) {
-        // Quirky pattern 2: Iterating over generic varargs
         for (T event : events) {
             sendMessage(event);
         }
     }
 
+    @Override
+    public <T extends OrderEvent, P> void sendCustomMessage(click.kamil.domain.CustomStateMachineMessage<T, P> customMessage) {
+        // Because CustomStateMachineMessage extends GenericMessage<T> and implements Message<T>,
+        // we can pass it directly to the state machine as long as T resolves to OrderEvent!
+        
+        // We cast it to Message<OrderEvent> to satisfy Mono's strict type requirements
+        org.springframework.messaging.Message<OrderEvent> msg = (org.springframework.messaging.Message<OrderEvent>) customMessage;
+        stateMachine.sendEvent(Mono.just(msg)).subscribe();
+    }
+
     @Override
     public <T extends IEvent & java.io.Serializable & Cloneable> T processQuirkyEvent(T event) {
         // Quirky pattern 3: Multiple bounds, returning the same generic type

state_machines/complex_multi_module_sm/web/pom.xml

@@ -24,5 +24,9 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-activemq</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-amqp</artifactId>
+        </dependency>
     </dependencies>
 </project>

state_machines/complex_multi_module_sm/web/src/main/java/click/kamil/web/RabbitOrderListener.java

@@ -0,0 +1,32 @@
+package click.kamil.web;
+
+import click.kamil.domain.CustomStateMachineMessage;
+import click.kamil.domain.OrderEvent;
+import click.kamil.service.StateMachineService;
+import org.springframework.amqp.rabbit.annotation.RabbitListener;
+import org.springframework.stereotype.Component;
+
+@Component
+public class RabbitOrderListener {
+
+    private final StateMachineService stateMachineService;
+
+    // Constructor Injection
+    public RabbitOrderListener(StateMachineService stateMachineService) {
+        this.stateMachineService = stateMachineService;
+    }
+
+    // Listens to RabbitMQ, constructs the custom class, triggers a state transition
+    @RabbitListener(queues = "order.custom.transition.queue")
+    public void handleCustomTransition(String payload) {
+        System.out.println("Received RabbitMQ message: " + payload);
+        
+        // Construct our custom event containing the generic payload and the enum state
+        CustomStateMachineMessage<OrderEvent, String> customMessage = 
+                new CustomStateMachineMessage<>(OrderEvent.PROCESS, "My Rabbit Custom Payload: " + payload);
+        
+        // Push the custom event into the state machine to perform the transition
+        stateMachineService.sendCustomMessage(customMessage);
+        System.out.println("Triggered PROCESS transition via custom message over RabbitMQ");
+    }
+}