GH-936 Add post processor for native hints

Resolves #936

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/FunctionTypeProcessor.java

@@ -0,0 +1,106 @@
+/*
+ * Copyright 2019-2022 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.cloud.function.context;
+
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+import org.springframework.aot.generate.GenerationContext;
+import org.springframework.aot.hint.MemberCategory;
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.beans.factory.aot.BeanFactoryInitializationAotContribution;
+import org.springframework.beans.factory.aot.BeanFactoryInitializationAotProcessor;
+import org.springframework.beans.factory.aot.BeanFactoryInitializationCode;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.cloud.function.context.catalog.FunctionTypeUtils;
+import org.springframework.cloud.function.context.config.FunctionContextUtils;
+
+/**
+ * Ensure that Function/Consumer input types are reflectively available.
+ *
+ * @author Oleg Zhurakousky
+ */
+public class FunctionTypeProcessor implements BeanFactoryInitializationAotProcessor {
+
+	@Override
+	public BeanFactoryInitializationAotContribution processAheadOfTime(ConfigurableListableBeanFactory beanFactory) {
+		Set<Class<?>> typeHints = new HashSet<>();
+
+		String[] names = beanFactory.getBeanDefinitionNames();
+		for (int i = 0; i < names.length; i++) {
+			String beanName = names[i];
+			Class<?> beanClass = beanFactory.getType(beanName);
+			if (this.isFunction(beanClass)) {
+				Type functionType = FunctionTypeUtils.discoverFunctionTypeFromClass(beanClass);
+
+				if (!(functionType instanceof ParameterizedType)) {
+					functionType = FunctionContextUtils.findType(beanFactory, beanName);
+				}
+				this.registerAllGenericTypes((ParameterizedType) functionType, typeHints);
+			}
+		}
+		return new ReflectiveProcessorBeanFactoryInitializationAotContribution(typeHints.toArray(Class[]::new));
+	}
+
+	private void registerAllGenericTypes(ParameterizedType type, Set<Class<?>> typeHints) {
+		Type[] types = type.getActualTypeArguments();
+		for (int i = 0; i < types.length; i++) {
+			Type functionParameterType = types[i];
+			String name = functionParameterType.getTypeName();
+			if (!isCoreJavaType(name)) {
+				typeHints.add(FunctionTypeUtils.getRawType(functionParameterType));
+			}
+			if (functionParameterType instanceof ParameterizedType) {
+				this.registerAllGenericTypes((ParameterizedType) functionParameterType, typeHints);
+			}
+		}
+	}
+
+	private boolean isCoreJavaType(String className) {
+		return className.startsWith("java.") || className.startsWith("javax.");
+	}
+
+	private boolean isFunction(Class<?> beanType) {
+		return Function.class.isAssignableFrom(beanType)
+				|| Consumer.class.isAssignableFrom(beanType)
+					|| Supplier.class.isAssignableFrom(beanType);
+	}
+
+	private static final class ReflectiveProcessorBeanFactoryInitializationAotContribution implements BeanFactoryInitializationAotContribution {
+
+		private final Class<?>[] typeHints;
+
+		private ReflectiveProcessorBeanFactoryInitializationAotContribution(Class<?>[] typeHints) {
+			this.typeHints = typeHints;
+		}
+
+		@Override
+		public void applyTo(GenerationContext generationContext, BeanFactoryInitializationCode beanFactoryInitializationCode) {
+			RuntimeHints runtimeHints = generationContext.getRuntimeHints();
+			for (int i = 0; i < typeHints.length; i++) {
+				runtimeHints.reflection().registerType(typeHints[i], MemberCategory.PUBLIC_FIELDS,
+						MemberCategory.INVOKE_DECLARED_METHODS, MemberCategory.INVOKE_DECLARED_CONSTRUCTORS);
+			}
+		}
+
+	}
+}

spring-cloud-function-context/src/main/resources/META-INF/spring/aot.factories

@@ -0,0 +1 @@
+org.springframework.beans.factory.aot.BeanFactoryInitializationAotProcessor=org.springframework.cloud.function.context.FunctionTypeProcessor