From e0e3cb7a546c6ad697ec9780cc15d30fdb5aa403 Mon Sep 17 00:00:00 2001
From: Andreas Mautsch <amautsch>
Date: Sat, 6 Jul 2024 14:57:45 +0200
Subject: [PATCH] changes

---
 doc/natsaspect/NatsListener.java       | 14 +++++
 doc/natsaspect/NatsListenerAspect.java | 76 ++++++++++++++++++++++++++
 2 files changed, 90 insertions(+)
 create mode 100644 doc/natsaspect/NatsListener.java
 create mode 100644 doc/natsaspect/NatsListenerAspect.java

diff --git a/doc/natsaspect/NatsListener.java b/doc/natsaspect/NatsListener.java
new file mode 100644
index 0000000..9f67410
--- /dev/null
+++ b/doc/natsaspect/NatsListener.java
@@ -0,0 +1,14 @@
+package org.goafabric.eventdispatcher.consumer;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.METHOD)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface NatsListener {
+    String consumerName();
+    String[] subjects() default {};
+}
+
diff --git a/doc/natsaspect/NatsListenerAspect.java b/doc/natsaspect/NatsListenerAspect.java
new file mode 100644
index 0000000..3c7a936
--- /dev/null
+++ b/doc/natsaspect/NatsListenerAspect.java
@@ -0,0 +1,76 @@
+package org.goafabric.eventdispatcher.consumer;
+
+
+import jakarta.annotation.PostConstruct;
+import org.aspectj.lang.annotation.Aspect;
+import org.goafabric.eventdispatcher.Application;
+import org.springframework.aop.support.AopUtils;
+import org.springframework.aot.hint.ExecutableMode;
+import org.springframework.aot.hint.MemberCategory;
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.aot.hint.RuntimeHintsRegistrar;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider;
+import org.springframework.context.annotation.ImportRuntimeHints;
+import org.springframework.core.type.filter.AnnotationTypeFilter;
+import org.springframework.stereotype.Component;
+import org.springframework.util.ClassUtils;
+import org.springframework.util.ReflectionUtils;
+
+import java.lang.reflect.Method;
+import java.util.Arrays;
+
+@Aspect
+@Component
+@ImportRuntimeHints(NatsListenerAspect.ApplicationRuntimeHints.class)
+public class NatsListenerAspect {
+
+    private final NatsSubscription natsSubscription;
+    private final ApplicationContext applicationContext;
+
+    @Autowired
+    public NatsListenerAspect(NatsSubscription natsSubscription, ApplicationContext applicationContext) {
+        this.natsSubscription = natsSubscription;
+        this.applicationContext = applicationContext;
+    }
+
+    @PostConstruct
+    public void init() {
+        Arrays.stream(applicationContext.getBeanDefinitionNames())
+                .filter(beanName -> !beanName.equals("natsListenerAspect"))
+                .forEach(beanName -> {
+                    var bean = applicationContext.getBean(beanName);
+                    Arrays.stream(AopUtils.getTargetClass(bean).getDeclaredMethods())
+                            .filter(method -> method.isAnnotationPresent(NatsListener.class))
+                            .forEach(method -> setupSubscription(bean, method, method.getAnnotation(NatsListener.class)));
+                });
+
+    }
+
+    private void setupSubscription(Object bean, Method method, NatsListener natsListener) {
+        Arrays.stream(natsListener.subjects()).forEach(subject -> {
+            natsSubscription.create(natsListener.consumerName(), subject, (msg, eventData) -> {
+                ReflectionUtils.invokeMethod(method, bean, msg.getSubject(), eventData);
+            });
+        });
+    }
+
+    static class ApplicationRuntimeHints implements RuntimeHintsRegistrar {
+        @Override
+        public void registerHints(RuntimeHints hints, ClassLoader classLoader) {
+            hints.reflection().registerType(NatsListenerAspect.class, MemberCategory.INVOKE_DECLARED_METHODS);
+
+            var scanner = new ClassPathScanningCandidateComponentProvider(false);
+            scanner.addIncludeFilter(new AnnotationTypeFilter(Component.class));
+            scanner.findCandidateComponents(Application.class.getPackage().getName()).forEach(beanDefinition -> {
+                try {
+                    Arrays.stream(ClassUtils.forName(beanDefinition.getBeanClassName(), classLoader).getDeclaredMethods())
+                            .filter(method -> method.isAnnotationPresent(NatsListener.class))
+                            .forEach(method -> hints.reflection().registerMethod(method, ExecutableMode.INVOKE));
+                } catch (ClassNotFoundException e) { throw new IllegalStateException(e); }
+            });
+        }
+
+    }
+}