From 6e123272dc67490d63ee90457f33a6a994bc08ce Mon Sep 17 00:00:00 2001
From: Oliver Drotbohm <oliver.drotbohm@broadcom.com>
Date: Thu, 12 Sep 2024 16:57:44 +0200
Subject: [PATCH] GH-816 - Properly guard for presence of jMolecules' @Module
 type.

As @Module is absent from the Kotlin flavor of jMolecules, code that refers to that is now guarded with a more specific check for that type in particular.
---
 .../core/ApplicationModuleInformation.java       |  2 +-
 .../org/springframework/modulith/core/Types.java | 16 +++++++++++++++-
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/spring-modulith-core/src/main/java/org/springframework/modulith/core/ApplicationModuleInformation.java b/spring-modulith-core/src/main/java/org/springframework/modulith/core/ApplicationModuleInformation.java
index 1a19ab2f..56dc066e 100644
--- a/spring-modulith-core/src/main/java/org/springframework/modulith/core/ApplicationModuleInformation.java
+++ b/spring-modulith-core/src/main/java/org/springframework/modulith/core/ApplicationModuleInformation.java
@@ -50,7 +50,7 @@ public static ApplicationModuleInformation of(JavaPackage javaPackage) {
 
 		var lookup = AnnotationLookup.of(javaPackage.toSingle(), __ -> true);
 
-		return JMoleculesTypes.isPresent() && JMoleculesModule.supports(lookup)
+		return JMoleculesTypes.isModulePresent() && JMoleculesModule.supports(lookup)
 				? new JMoleculesModule(lookup)
 				: new SpringModulithModule(lookup);
 	}
diff --git a/spring-modulith-core/src/main/java/org/springframework/modulith/core/Types.java b/spring-modulith-core/src/main/java/org/springframework/modulith/core/Types.java
index 0a7d5b80..661a1418 100644
--- a/spring-modulith-core/src/main/java/org/springframework/modulith/core/Types.java
+++ b/spring-modulith-core/src/main/java/org/springframework/modulith/core/Types.java
@@ -52,21 +52,35 @@ static class JMoleculesTypes {
 		private static final String MODULE = ANNOTATION_PACKAGE + ".Module";
 
 		private static final boolean PRESENT = ClassUtils.isPresent(AT_ENTITY, JMoleculesTypes.class.getClassLoader());
+		private static final boolean MODULE_PRESENT = ClassUtils.isPresent(MODULE, JMoleculesTypes.class.getClassLoader());
 
 		static final String AT_DOMAIN_EVENT_HANDLER = BASE_PACKAGE + ".event.annotation.DomainEventHandler";
 		static final String AT_DOMAIN_EVENT = BASE_PACKAGE + ".event.annotation.DomainEvent";
 		static final String DOMAIN_EVENT = BASE_PACKAGE + ".event.types.DomainEvent";
 
+		/**
+		 * Returns whether jMolecules is generally present.
+		 *
+		 * @see #isModulePresent()
+		 */
 		public static boolean isPresent() {
 			return PRESENT;
 		}
 
+		/**
+		 * Returns whether the jMolecules {@link Module} type is present. We need to guard for this explicitly as the Kotlin
+		 * variant of jMolecules DDD does not ship that type.
+		 */
+		public static boolean isModulePresent() {
+			return MODULE_PRESENT;
+		}
+
 		@Nullable
 		@SuppressWarnings("unchecked")
 		public static Class<? extends Annotation> getModuleAnnotationTypeIfPresent() {
 
 			try {
-				return isPresent()
+				return isModulePresent()
 						? (Class<? extends Annotation>) ClassUtils.forName(MODULE, JMoleculesTypes.class.getClassLoader())
 						: null;
 			} catch (Exception o_O) {