Inspect bean definition more thoroughly for factory arguments

Fixes gh-153

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

@@ -20,6 +20,8 @@ import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -42,6 +44,7 @@ import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.config.ConstructorArgumentValues.ValueHolder;
 import org.springframework.beans.factory.support.AbstractBeanDefinition;
+import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.cloud.function.context.FunctionCatalog;
 import org.springframework.cloud.function.context.FunctionRegistration;
@@ -553,15 +556,48 @@ public class ContextFunctionCatalogAutoConfiguration {
 				MethodMetadataReadingVisitor visitor) {
 			Class<?> factory = ClassUtils
 					.resolveClassName(visitor.getDeclaringClassName(), null);
+			Class<?>[] params = getParamTypes(factory, definition);
+			Method method = ReflectionUtils.findMethod(factory, visitor.getMethodName(),
+					params);
+			Type type = method.getGenericReturnType();
+			return type;
+		}
+
+		private Method[] getCandidateMethods(final Class<?> factoryClass,
+				final RootBeanDefinition mbd) {
+			if (System.getSecurityManager() != null) {
+				return AccessController.doPrivileged(new PrivilegedAction<Method[]>() {
+					@Override
+					public Method[] run() {
+						return (mbd.isNonPublicAccessAllowed()
+								? ReflectionUtils.getAllDeclaredMethods(factoryClass)
+								: factoryClass.getMethods());
+					}
+				});
+			}
+			else {
+				return (mbd.isNonPublicAccessAllowed()
+						? ReflectionUtils.getAllDeclaredMethods(factoryClass)
+						: factoryClass.getMethods());
+			}
+		}
+
+		private Class<?>[] getParamTypes(Class<?> factory,
+				AbstractBeanDefinition definition) {
+			if (definition instanceof RootBeanDefinition) {
+				RootBeanDefinition root = (RootBeanDefinition) definition;
+				for (Method method : getCandidateMethods(factory, root)) {
+					if (root.isFactoryMethod(method)) {
+						return method.getParameterTypes();
+					}
+				}
+			}
 			List<Class<?>> params = new ArrayList<>();
 			for (ValueHolder holder : definition.getConstructorArgumentValues()
 					.getIndexedArgumentValues().values()) {
 				params.add(ClassUtils.resolveClassName(holder.getType(), null));
 			}
-			Method method = ReflectionUtils.findMethod(factory, visitor.getMethodName(),
-					params.toArray(new Class<?>[0]));
-			Type type = method.getGenericReturnType();
-			return type;
+			return params.toArray(new Class<?>[0]);
 		}
 
 		private Object getField(Object target, String name) {

spring-cloud-function-context/src/test/java/org/springframework/cloud/function/context/config/ContextFunctionCatalogAutoConfigurationTests.java

@@ -46,6 +46,7 @@ import org.springframework.cloud.function.context.FunctionCatalog;
 import org.springframework.cloud.function.context.FunctionRegistration;
 import org.springframework.cloud.function.context.FunctionScan;
 import org.springframework.cloud.function.context.catalog.FunctionInspector;
+import org.springframework.cloud.function.inject.FooConfiguration;
 import org.springframework.cloud.function.scan.ScannedFunction;
 import org.springframework.cloud.function.test.GenericFunction;
 import org.springframework.context.ConfigurableApplicationContext;
@@ -120,7 +121,26 @@ public class ContextFunctionCatalogAutoConfigurationTests {
 				.isEqualTo(String.class);
 		assertThat(inspector.getInputType(catalog.lookup(Consumer.class, "foos")))
 				.isEqualTo(Foo.class);
+	}
 
+	@Test
+	public void dependencyInjection() {
+		create(DependencyInjectionConfiguration.class);
+		assertThat(context.getBean("foos")).isInstanceOf(Function.class);
+		assertThat(catalog.<Function<?, ?>>lookup(Function.class, "foos"))
+				.isInstanceOf(Function.class);
+		assertThat(inspector.getInputType(catalog.lookup(Function.class, "foos")))
+				.isEqualTo(String.class);
+	}
+
+	@Test
+	public void externalDependencyInjection() {
+		create(ExternalDependencyConfiguration.class);
+		assertThat(context.getBean("foos")).isInstanceOf(Function.class);
+		assertThat(catalog.<Function<?, ?>>lookup(Function.class, "foos"))
+				.isInstanceOf(Function.class);
+		assertThat(inspector.getInputType(catalog.lookup(Function.class, "foos")))
+				.isEqualTo(String.class);
 	}
 
 	@Test
@@ -523,6 +543,32 @@ public class ContextFunctionCatalogAutoConfigurationTests {
 		}
 	}
 
+	@EnableAutoConfiguration
+	@Configuration
+	protected static class DependencyInjectionConfiguration {
+
+		@Bean
+		public Function<String, Foo> foos(String foo) {
+			return value -> new Foo(foo + ": " + value.toUpperCase());
+		}
+
+		@Bean
+		public String value() {
+			return "Hello";
+		}
+	}
+
+	@EnableAutoConfiguration
+	@Configuration
+	@ComponentScan(basePackageClasses = FooConfiguration.class)
+	protected static class ExternalDependencyConfiguration {
+
+		@Bean
+		public String value() {
+			return "Hello";
+		}
+	}
+
 	@EnableAutoConfiguration
 	@Configuration
 	protected static class AmbiguousConfiguration {

spring-cloud-function-context/src/test/java/org/springframework/cloud/function/inject/FooConfiguration.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2016-2017 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
+ *
+ *      http://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.inject;
+
+import java.util.function.Function;
+
+import org.springframework.cloud.function.context.config.ContextFunctionCatalogAutoConfigurationTests.Foo;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class FooConfiguration {
+	@Bean
+	public Function<String, Foo> foos(String foo) {
+		return value -> new Foo(foo + ": " + value.toUpperCase());
+	}
+}