GH-928 - Polishing.

License headers, formatting, null checks.

spring-modulith-observability/src/main/java/org/springframework/modulith/observability/DefaultModulithObservationConvention.java

@@ -1,7 +1,20 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.springframework.modulith.observability;
 
-import java.lang.reflect.Method;
-
 import io.micrometer.common.KeyValues;
 
 import org.springframework.modulith.observability.ModulithObservations.HighKeys;
@@ -11,40 +24,62 @@ import org.springframework.modulith.observability.ModulithObservations.LowKeys;
  * Default implementation of {@link ModulithObservationConvention}.
  *
  * @author Marcin Grzejszczak
+ * @author Oliver Drotbohm
  * @since 1.4
  */
-public class DefaultModulithObservationConvention implements ModulithObservationConvention {
+class DefaultModulithObservationConvention implements ModulithObservationConvention {
 
+	/*
+	 * (non-Javadoc)
+	 * @see io.micrometer.observation.ObservationConvention#getLowCardinalityKeyValues(io.micrometer.observation.Observation.Context)
+	 */
 	@Override
 	public KeyValues getLowCardinalityKeyValues(ModulithContext context) {
-		KeyValues keyValues = KeyValues.of(LowKeys.MODULE_KEY.withValue(context.getModule().getIdentifier().toString()));
-		if (isEventListener(context)) {
-			return keyValues.and(LowKeys.INVOCATION_TYPE.withValue("event-listener"));
-		}
-		return keyValues;
+
+		var keyValues = KeyValues.of(LowKeys.MODULE_KEY.withValue(context.getModule().getIdentifier().toString()));
+
+		return isEventListener(context)
+				? keyValues.and(LowKeys.INVOCATION_TYPE.withValue("event-listener"))
+				: keyValues;
+	}
+
+	/*
+	 *
+	 * (non-Javadoc)
+	 * @see io.micrometer.observation.ObservationConvention#getHighCardinalityKeyValues(io.micrometer.observation.Observation.Context)
+	 */
+	@Override
+	public KeyValues getHighCardinalityKeyValues(ModulithContext context) {
+
+		var method = context.getInvocation().getMethod();
+
+		return KeyValues.of(HighKeys.MODULE_METHOD.withValue(method.getName()));
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see io.micrometer.observation.ObservationConvention#getName()
+	 */
+	@Override
+	public String getName() {
+		return "module.requests";
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see io.micrometer.observation.ObservationConvention#getContextualName(io.micrometer.observation.Observation.Context)
+	 */
+	@Override
+	public String getContextualName(ModulithContext context) {
+		return "[" + context.getApplicationName() + "] " + context.getModule().getDisplayName();
 	}
 
 	private boolean isEventListener(ModulithContext context) {
+
 		try {
 			return context.getModule().isEventListenerInvocation(context.getInvocation());
 		} catch (Exception e) {
 			return false;
 		}
 	}
-
-	@Override
-	public KeyValues getHighCardinalityKeyValues(ModulithContext context) {
-		Method method = context.getInvocation().getMethod();
-		return KeyValues.of(HighKeys.MODULE_METHOD.withValue(method.getName()));
-	}
-
-	@Override
-	public String getName() {
-		return "module.requests";
-	}
-
-	@Override
-	public String getContextualName(ModulithContext context) {
-		return "[" + context.getApplicationName() + "] " + context.getModule().getDisplayName();
-	}
 }

spring-modulith-observability/src/main/java/org/springframework/modulith/observability/DefaultObservedModule.java

@@ -25,7 +25,6 @@ import org.springframework.aop.support.AopUtils;
 import org.springframework.modulith.core.ApplicationModule;
 import org.springframework.modulith.core.ApplicationModuleIdentifier;
 import org.springframework.modulith.core.ApplicationModules;
-import org.springframework.modulith.core.ArchitecturallyEvidentType;
 import org.springframework.modulith.core.ArchitecturallyEvidentType.ReferenceMethod;
 import org.springframework.modulith.core.FormattableType;
 import org.springframework.modulith.core.SpringBean;
@@ -163,7 +162,6 @@ class DefaultObservedModule implements ObservedModule {
 		var targetClass = advised.getTargetClass();
 
 		if (module.contains(targetClass)) {
-
 			return AopUtils.getMostSpecificMethod(method, targetClass);
 		}
 

spring-modulith-observability/src/main/java/org/springframework/modulith/observability/ModuleEntryInterceptor.java

@@ -15,8 +15,8 @@
  */
 package org.springframework.modulith.observability;
 
-import io.micrometer.common.KeyValue;
 import io.micrometer.observation.Observation;
+import io.micrometer.observation.Observation.Scope;
 import io.micrometer.observation.ObservationRegistry;
 
 import java.util.HashMap;
@@ -33,16 +33,22 @@ import org.springframework.modulith.core.ApplicationModuleIdentifier;
 import org.springframework.modulith.observability.ModulithObservations.LowKeys;
 import org.springframework.util.Assert;
 
+/**
+ * {@link MethodInterceptor} to create {@link Observation}s.
+ *
+ * @author Marcin Grzejszczak
+ * @author Oliver Drotbohm
+ */
 class ModuleEntryInterceptor implements MethodInterceptor {
 
-	private static Logger LOGGER = LoggerFactory.getLogger(ModuleEntryInterceptor.class);
+	private static final Logger LOGGER = LoggerFactory.getLogger(ModuleEntryInterceptor.class);
 	private static Map<ApplicationModuleIdentifier, ModuleEntryInterceptor> CACHE = new HashMap<>();
 
 	private static final ModulithObservationConvention DEFAULT = new DefaultModulithObservationConvention();
 
 	private final ObservedModule module;
 	private final ObservationRegistry observationRegistry;
-	@Nullable private final ModulithObservationConvention customModulithObservationConvention;
+	private final @Nullable ModulithObservationConvention customModulithObservationConvention;
 	private final Environment environment;
 
 	/**
@@ -103,7 +109,8 @@ class ModuleEntryInterceptor implements MethodInterceptor {
 		String currentModule = null;
 
 		if (currentObservation != null) {
-			KeyValue moduleKey = currentObservation.getContextView().getLowCardinalityKeyValue(LowKeys.MODULE_KEY.asString());
+
+			var moduleKey = currentObservation.getContextView().getLowCardinalityKeyValue(LowKeys.MODULE_KEY.asString());
 			currentModule = moduleKey != null ? moduleKey.getValue() : null;
 		}
 
@@ -116,18 +123,26 @@ class ModuleEntryInterceptor implements MethodInterceptor {
 
 		LOGGER.trace("Entering {} via {}.", module.getDisplayName(), invokedMethod);
 
-		ModulithContext modulithContext = new ModulithContext(module, invocation, environment);
+		var modulithContext = new ModulithContext(module, invocation, environment);
 		var observation = Observation.createNotStarted(customModulithObservationConvention, DEFAULT,
 				() -> modulithContext, observationRegistry);
-		try (Observation.Scope scope = observation.start().openScope()) {
-			Object proceed = invocation.proceed();
+
+		try (Scope scope = observation.start().openScope()) {
+
+			var proceed = invocation.proceed();
 			observation.event(ModulithObservations.Events.EVENT_PUBLICATION_SUCCESS);
+
 			return proceed;
+
 		} catch (Exception ex) {
+
 			observation.error(ex);
 			observation.event(ModulithObservations.Events.EVENT_PUBLICATION_FAILURE);
+
 			throw ex;
+
 		} finally {
+
 			LOGGER.trace("Leaving {}", module.getDisplayName());
 			observation.stop();
 		}

spring-modulith-observability/src/main/java/org/springframework/modulith/observability/ModuleEventListener.java

@@ -39,13 +39,15 @@ public class ModuleEventListener implements ApplicationListener<ApplicationEvent
 	private final Supplier<MeterRegistry> meterRegistry;
 
 	/**
-	 * Creates a new {@link ModuleEventListener} for the given {@link ApplicationModulesRuntime} and {@link ObservationRegistry} and {@link MeterRegistry}.
+	 * Creates a new {@link ModuleEventListener} for the given {@link ApplicationModulesRuntime} and
+	 * {@link ObservationRegistry} and {@link MeterRegistry}.
 	 *
 	 * @param runtime must not be {@literal null}.
 	 * @param observationRegistrySupplier must not be {@literal null}.
+	 * @param meterRegistrySupplier must not be {@literal null}.
 	 */
-	public ModuleEventListener(ApplicationModulesRuntime runtime, Supplier<ObservationRegistry> observationRegistrySupplier,
-			Supplier<MeterRegistry> meterRegistrySupplier) {
+	public ModuleEventListener(ApplicationModulesRuntime runtime,
+			Supplier<ObservationRegistry> observationRegistrySupplier, Supplier<MeterRegistry> meterRegistrySupplier) {
 
 		Assert.notNull(runtime, "ApplicationModulesRuntime must not be null!");
 		Assert.notNull(observationRegistrySupplier, "ObservationRegistry must not be null!");
@@ -82,8 +84,10 @@ public class ModuleEventListener implements ApplicationListener<ApplicationEvent
 			return;
 		}
 
-		MeterRegistry registry = meterRegistry.get();
+		var registry = meterRegistry.get();
+
 		if (registry != null) {
+
 			Counter.builder(ModulithMetrics.EVENTS.getName()) //
 					.tags(ModulithMetrics.LowKeys.EVENT_TYPE.name().toLowerCase(), event.getClass().getSimpleName()) //
 					.tags(ModulithMetrics.LowKeys.MODULE_NAME.name().toLowerCase(), moduleByType.getDisplayName()) //

spring-modulith-observability/src/main/java/org/springframework/modulith/observability/ModulePassingObservationFilter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022-2024 the original author or authors.
+ * Copyright 2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,30 +16,46 @@
 package org.springframework.modulith.observability;
 
 import io.micrometer.observation.Observation;
+import io.micrometer.observation.Observation.ContextView;
 import io.micrometer.observation.ObservationFilter;
 
 /**
- * Ensures that {@link ModulithObservations.LowKeys#MODULE_KEY} gets propagated from parent
- * to child.
- * 
+ * Ensures that {@link ModulithObservations.LowKeys#MODULE_KEY} gets propagated from parent to child.
+ *
  * @author Marcin Grzejszczak
+ * @author Oliver Drotbohm
  * @since 1.4
  */
 public class ModulePassingObservationFilter implements ObservationFilter {
 
-	@Override 
+	/*
+	 * (non-Javadoc)
+	 * @see io.micrometer.observation.ObservationFilter#map(io.micrometer.observation.Observation.Context)
+	 */
+	@Override
 	public Observation.Context map(Observation.Context context) {
+
 		if (isModuleKeyValueAbsentInCurrent(context) && isModuleKeyValuePresentInParent(context)) {
-			return context.addLowCardinalityKeyValue(ModulithObservations.LowKeys.MODULE_KEY.withValue(context.getParentObservation().getContextView().getLowCardinalityKeyValue(ModulithObservations.LowKeys.MODULE_KEY.asString()).getValue()));
+
+			var moduleKey = ModulithObservations.LowKeys.MODULE_KEY;
+
+			return context.addLowCardinalityKeyValue(moduleKey.withValue(context.getParentObservation().getContextView()
+					.getLowCardinalityKeyValue(moduleKey.asString()).getValue()));
 		}
+
 		return context;
 	}
 
-	private static boolean isModuleKeyValueAbsentInCurrent(Observation.ContextView context) {
+	private static boolean isModuleKeyValueAbsentInCurrent(ContextView context) {
 		return context.getLowCardinalityKeyValue(ModulithObservations.LowKeys.MODULE_KEY.asString()) == null;
 	}
 
-	private static boolean isModuleKeyValuePresentInParent(Observation.ContextView context) {
-		return context.getParentObservation() != null && context.getParentObservation().getContextView().getLowCardinalityKeyValue(ModulithObservations.LowKeys.MODULE_KEY.asString()) != null;
+	private static boolean isModuleKeyValuePresentInParent(ContextView context) {
+
+		var parentObservation = context.getParentObservation();
+
+		return parentObservation != null
+				&& parentObservation.getContextView()
+						.getLowCardinalityKeyValue(ModulithObservations.LowKeys.MODULE_KEY.asString()) != null;
 	}
-}
+}

spring-modulith-observability/src/main/java/org/springframework/modulith/observability/ModulithContext.java

@@ -1,39 +1,67 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.springframework.modulith.observability;
 
-import io.micrometer.observation.Observation;
-import org.aopalliance.intercept.MethodInvocation;
+import io.micrometer.observation.Observation.Context;
 
+import org.aopalliance.intercept.MethodInvocation;
 import org.springframework.core.env.Environment;
+import org.springframework.util.Assert;
 
 /**
- * A {@link Observation.Context} for Modulithic applications.
+ * A {@link Context} for Modulithic applications.
  *
  * @author Marcin Grzejsczak
+ * @author Oliver Drotbohm
  * @since 1.4
  */
-public class ModulithContext extends Observation.Context {
+public class ModulithContext extends Context {
 
-  private final ObservedModule module;
+	private final ObservedModule module;
+	private final MethodInvocation invocation;
+	private final String applicationName;
 
-  private final MethodInvocation invocation;
+	/**
+	 * Creates a new {@link ModulithContext} for the given {@link ObservedModule}, {@link MethodInvocation} and
+	 * {@link Environment}.
+	 *
+	 * @param module must not be {@literal null}.
+	 * @param invocation must not be {@literal null}.
+	 * @param environment must not be {@literal null}.
+	 */
+	public ModulithContext(ObservedModule module, MethodInvocation invocation, Environment environment) {
 
-  private final String applicationName;
+		Assert.notNull(module, "ObservedModule must not be null!");
+		Assert.notNull(invocation, "MethodInvocation must not be null!");
+		Assert.notNull(environment, "Environment must not be null!");
 
-  public ModulithContext(ObservedModule module, MethodInvocation invocation, Environment environment) {
-    this.module = module;
-    this.invocation = invocation;
-    this.applicationName = environment.getProperty("spring.application.name");
-  }
+		this.module = module;
+		this.invocation = invocation;
+		this.applicationName = environment.getProperty("spring.application.name");
+	}
 
-  public ObservedModule getModule() {
-    return module;
-  }
+	public ObservedModule getModule() {
+		return module;
+	}
 
-  public MethodInvocation getInvocation() {
-    return invocation;
-  }
+	public MethodInvocation getInvocation() {
+		return invocation;
+	}
 
-  public String getApplicationName() {
-    return applicationName;
-  }
+	public String getApplicationName() {
+		return applicationName;
+	}
 }

spring-modulith-observability/src/main/java/org/springframework/modulith/observability/ModulithMetrics.java

@@ -1,25 +1,58 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.springframework.modulith.observability;
 
 import io.micrometer.common.docs.KeyName;
 import io.micrometer.core.instrument.Meter;
 import io.micrometer.core.instrument.docs.MeterDocumentation;
 
+/**
+ * @author Marcin Grzejszczak
+ * @author Oliver Drotbohm
+ * @since 1.4
+ */
 enum ModulithMetrics implements MeterDocumentation {
 
 	/**
 	 * Counter for the events.
 	 */
 	EVENTS {
+
+		/*
+		 * (non-Javadoc)
+		 * @see io.micrometer.core.instrument.docs.MeterDocumentation#getName()
+		 */
 		@Override
 		public String getName() {
 			return "modulith.events.processed";
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see io.micrometer.core.instrument.docs.MeterDocumentation#getType()
+		 */
 		@Override
 		public Meter.Type getType() {
 			return Meter.Type.COUNTER;
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see io.micrometer.core.instrument.docs.MeterDocumentation#getKeyNames()
+		 */
 		@Override
 		public KeyName[] getKeyNames() {
 			return LowKeys.values();
@@ -31,6 +64,11 @@ enum ModulithMetrics implements MeterDocumentation {
 		 * Type of the emitted event.
 		 */
 		EVENT_TYPE {
+
+			/*
+			 * (non-Javadoc)
+			 * @see io.micrometer.common.docs.KeyName#asString()
+			 */
 			@Override
 			public String asString() {
 				return "event.type";
@@ -41,6 +79,11 @@ enum ModulithMetrics implements MeterDocumentation {
 		 * Name of the module.
 		 */
 		MODULE_NAME {
+
+			/*
+			 * (non-Javadoc)
+			 * @see io.micrometer.common.docs.KeyName#asString()
+			 */
 			@Override
 			public String asString() {
 				return "module.name";

spring-modulith-observability/src/main/java/org/springframework/modulith/observability/ModulithObservationConvention.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.springframework.modulith.observability;
 
 import io.micrometer.observation.Observation.Context;
@@ -11,8 +26,12 @@ import io.micrometer.observation.ObservationConvention;
  */
 public interface ModulithObservationConvention extends ObservationConvention<ModulithContext> {
 
-  @Override
-  default boolean supportsContext(Context context) {
-    return context instanceof ModulithContext;
-  }
+	/*
+	 * (non-Javadoc)
+	 * @see io.micrometer.observation.ObservationConvention#supportsContext(io.micrometer.observation.Observation.Context)
+	 */
+	@Override
+	default boolean supportsContext(Context context) {
+		return context instanceof ModulithContext;
+	}
 }

spring-modulith-observability/src/main/java/org/springframework/modulith/observability/ModulithObservations.java

@@ -1,8 +1,24 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.springframework.modulith.observability;
 
 import io.micrometer.common.docs.KeyName;
 import io.micrometer.observation.Observation;
 import io.micrometer.observation.Observation.Context;
+import io.micrometer.observation.Observation.Event;
 import io.micrometer.observation.ObservationConvention;
 import io.micrometer.observation.docs.ObservationDocumentation;
 
@@ -12,19 +28,40 @@ enum ModulithObservations implements ObservationDocumentation {
 	 * Observation related to entering a module.
 	 */
 	MODULE_ENTRY {
-		@Override public Class<? extends ObservationConvention<? extends Context>> getDefaultConvention() {
+
+		/*
+		 * (non-Javadoc)
+		 * @see io.micrometer.observation.docs.ObservationDocumentation#getDefaultConvention()
+		 */
+		@Override
+		public Class<? extends ObservationConvention<? extends Context>> getDefaultConvention() {
 			return DefaultModulithObservationConvention.class;
 		}
 
-		@Override public KeyName[] getLowCardinalityKeyNames() {
+		/*
+		 * (non-Javadoc)
+		 * @see io.micrometer.observation.docs.ObservationDocumentation#getLowCardinalityKeyNames()
+		 */
+		@Override
+		public KeyName[] getLowCardinalityKeyNames() {
 			return LowKeys.values();
 		}
 
-		@Override public KeyName[] getHighCardinalityKeyNames() {
+		/*
+		 * (non-Javadoc)
+		 * @see io.micrometer.observation.docs.ObservationDocumentation#getHighCardinalityKeyNames()
+		 */
+		@Override
+		public KeyName[] getHighCardinalityKeyNames() {
 			return HighKeys.values();
 		}
 
-		@Override public Observation.Event[] getEvents() {
+		/*
+		 * (non-Javadoc)
+		 * @see io.micrometer.observation.docs.ObservationDocumentation#getEvents()
+		 */
+		@Override
+		public Observation.Event[] getEvents() {
 			return Events.values();
 		}
 	};
@@ -35,7 +72,13 @@ enum ModulithObservations implements ObservationDocumentation {
 		 * Name of the module.
 		 */
 		MODULE_KEY {
-			@Override public String asString() {
+
+			/*
+			 * (non-Javadoc)
+			 * @see io.micrometer.common.docs.KeyName#asString()
+			 */
+			@Override
+			public String asString() {
 				return "module.key";
 			}
 		},
@@ -44,7 +87,13 @@ enum ModulithObservations implements ObservationDocumentation {
 		 * Type of invocation (e.g. event listener).
 		 */
 		INVOCATION_TYPE {
-			@Override public String asString() {
+
+			/*
+			 * (non-Javadoc)
+			 * @see io.micrometer.common.docs.KeyName#asString()
+			 */
+			@Override
+			public String asString() {
 				return "module.invocation-type";
 			}
 		}
@@ -55,23 +104,35 @@ enum ModulithObservations implements ObservationDocumentation {
 		 * Method executed on a module.
 		 */
 		MODULE_METHOD {
-			@Override public String asString() {
+			@Override
+			public String asString() {
 				return "module.method";
 			}
 		}
 	}
 
-	enum Events implements Observation.Event {
+	enum Events implements Event {
 
 		/**
 		 * Published when an event is sent successfully.
 		 */
 		EVENT_PUBLICATION_SUCCESS {
-			@Override public String getName() {
+
+			/*
+			 * (non-Javadoc)
+			 * @see io.micrometer.observation.Observation.Event#getName()
+			 */
+			@Override
+			public String getName() {
 				return "event.publication.success";
 			}
 
-			@Override public String getContextualName() {
+			/*
+			 * (non-Javadoc)
+			 * @see io.micrometer.observation.Observation.Event#getContextualName()
+			 */
+			@Override
+			public String getContextualName() {
 				return getName();
 			}
 		},
@@ -80,11 +141,22 @@ enum ModulithObservations implements ObservationDocumentation {
 		 * Published when an event is sent with a failure.
 		 */
 		EVENT_PUBLICATION_FAILURE {
-			@Override public String getName() {
+
+			/*
+			 * (non-Javadoc)
+			 * @see io.micrometer.observation.Observation.Event#getName()
+			 */
+			@Override
+			public String getName() {
 				return "event.publication.failure";
 			}
 
-			@Override public String getContextualName() {
+			/*
+			 * (non-Javadoc)
+			 * @see io.micrometer.observation.Observation.Event#getContextualName()
+			 */
+			@Override
+			public String getContextualName() {
 				return getName();
 			}
 		}

spring-modulith-observability/src/main/java/org/springframework/modulith/observability/SpringDataRestModuleObservabilityBeanPostProcessor.java

@@ -19,10 +19,8 @@ import io.micrometer.observation.ObservationRegistry;
 
 import java.util.function.Supplier;
 
-import org.aopalliance.aop.Advice;
 import org.aopalliance.intercept.MethodInterceptor;
 import org.aopalliance.intercept.MethodInvocation;
-import org.springframework.aop.Advisor;
 import org.springframework.aop.support.DefaultPointcutAdvisor;
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.config.BeanPostProcessor;
@@ -30,6 +28,7 @@ import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.env.Environment;
 import org.springframework.data.rest.webmvc.BasePathAwareController;
 import org.springframework.data.rest.webmvc.RootResourceInformation;
+import org.springframework.lang.Nullable;
 import org.springframework.modulith.core.ApplicationModule;
 import org.springframework.modulith.core.ApplicationModules;
 import org.springframework.modulith.runtime.ApplicationModulesRuntime;
@@ -37,22 +36,25 @@ import org.springframework.util.Assert;
 
 /**
  * @author Oliver Drotbohm
+ * @author Marcin Grzejszczak
  */
-public class SpringDataRestModuleObservabilityBeanPostProcessor extends ModuleObservabilitySupport implements BeanPostProcessor {
+public class SpringDataRestModuleObservabilityBeanPostProcessor extends ModuleObservabilitySupport
+		implements BeanPostProcessor {
 
 	private final ApplicationModulesRuntime runtime;
 	private final Supplier<ObservationRegistry> observationRegistry;
 	private final Environment environment;
 
 	/**
-	 * Creates a new {@link SpringDataRestModuleObservabilityBeanPostProcessor} for the given {@link ApplicationModulesRuntime}
-	 * and {@link ObservationRegistry}.
+	 * Creates a new {@link SpringDataRestModuleObservabilityBeanPostProcessor} for the given
+	 * {@link ApplicationModulesRuntime} and {@link ObservationRegistry}.
 	 *
 	 * @param runtime must not be {@literal null}.
 	 * @param observationRegistry must not be {@literal null}.
 	 * @param environment must not be {@literal null}.
 	 */
-	public SpringDataRestModuleObservabilityBeanPostProcessor(ApplicationModulesRuntime runtime, Supplier<ObservationRegistry> observationRegistry, Environment environment) {
+	public SpringDataRestModuleObservabilityBeanPostProcessor(ApplicationModulesRuntime runtime,
+			Supplier<ObservationRegistry> observationRegistry, Environment environment) {
 
 		Assert.notNull(runtime, "ApplicationModulesRuntime must not be null!");
 		Assert.notNull(observationRegistry, "ObservationRegistry must not be null!");
@@ -75,8 +77,8 @@ public class SpringDataRestModuleObservabilityBeanPostProcessor extends ModuleOb
 			return bean;
 		}
 
-		Advice interceptor = new DataRestControllerInterceptor(runtime, observationRegistry, environment);
-		Advisor advisor = new DefaultPointcutAdvisor(interceptor);
+		var interceptor = new DataRestControllerInterceptor(runtime, observationRegistry, environment);
+		var advisor = new DefaultPointcutAdvisor(interceptor);
 
 		return addAdvisor(bean, advisor, it -> it.setProxyTargetClass(true));
 	}
@@ -90,11 +92,12 @@ public class SpringDataRestModuleObservabilityBeanPostProcessor extends ModuleOb
 		/**
 		 * Creates a new {@link DataRestControllerInterceptor} for the given {@link ApplicationModules} and {@link Tracer}.
 		 *
-		 * @param modules             must not be {@literal null}.
+		 * @param modules must not be {@literal null}.
 		 * @param observationRegistry must not be {@literal null}.
-		 * @param environment         must not be {@literal null}.
+		 * @param environment must not be {@literal null}.
 		 */
-		private DataRestControllerInterceptor(Supplier<ApplicationModules> modules, Supplier<ObservationRegistry> observationRegistry,
+		private DataRestControllerInterceptor(Supplier<ApplicationModules> modules,
+				Supplier<ObservationRegistry> observationRegistry,
 				Environment environment) {
 
 			Assert.notNull(modules, "ApplicationModules must not be null!");
@@ -124,6 +127,7 @@ public class SpringDataRestModuleObservabilityBeanPostProcessor extends ModuleOb
 			return ModuleEntryInterceptor.of(observed, observationRegistry.get(), environment).invoke(invocation);
 		}
 
+		@Nullable
 		private ApplicationModule getModuleFrom(Object[] arguments) {
 
 			for (Object argument : arguments) {

spring-modulith-observability/src/test/java/org/springframework/modulith/observability/ModuleObservabilityBeanPostProcessorIntegrationTests.java

@@ -38,13 +38,14 @@ import org.springframework.scheduling.annotation.AsyncAnnotationAdvisor;
  * Integration tests for {@link ModuleObservabilityBeanPostProcessor}.
  *
  * @author Oliver Drotbohm
+ * @author Marcin Grzejszczak
  */
 class ModuleObservabilityBeanPostProcessorIntegrationTests {
 
 	@Test
 	void decoratesExposedComponentsWithTracingInterceptor() {
 
-		SampleComponent bean = SpringApplication
+		var bean = SpringApplication
 				.run(new Class<?>[] { ExampleApplication.class, ModuleObservabilityConfiguration.class }, new String[] {})
 				.getBean(SampleComponent.class);
 
@@ -62,13 +63,15 @@ class ModuleObservabilityBeanPostProcessorIntegrationTests {
 	@Configuration
 	static class ModuleObservabilityConfiguration {
 
-		@Bean ModuleObservabilityBeanPostProcessor foo(ConfigurableApplicationContext context) {
+		@Bean
+		ModuleObservabilityBeanPostProcessor foo(ConfigurableApplicationContext context) {
 
 			var runtime = ApplicationRuntime.of(context);
 			var modulesRuntime = new ApplicationModulesRuntime(() -> TestApplicationModules.of(ExampleApplication.class),
 					runtime);
 
-			return new ModuleObservabilityBeanPostProcessor(modulesRuntime, () -> ObservationRegistry.NOOP, context.getBeanFactory(), context.getEnvironment());
+			return new ModuleObservabilityBeanPostProcessor(modulesRuntime, () -> ObservationRegistry.NOOP,
+					context.getBeanFactory(), context.getEnvironment());
 		}
 	}
 

spring-modulith-observability/src/test/java/org/springframework/modulith/observability/ModuleObservabilityBeanPostProcessorUnitTests.java

@@ -32,6 +32,7 @@ import org.springframework.modulith.runtime.ApplicationModulesRuntime;
  * Unit tests for {@link ModuleObservabilityBeanPostProcessor}.
  *
  * @author Oliver Drotbohm
+ * @author Marcin Grzejszczak
  */
 class ModuleObservabilityBeanPostProcessorUnitTests {