Support *Aware ImportBeanDefinitionRegistars

Implementations of Spring's ImportBeanDefinitionRegistrar interface may
now implement any of the following *Aware interfaces and have their
respective methods called prior to #registerBeanDefinitions:

 - BeanFactoryAware
 - BeanClassLoaderAware
 - ResourceLoaderAware

Issue: SPR-9568

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java

@@ -16,8 +16,6 @@
 
 package org.springframework.context.annotation;
 
-import static org.springframework.context.annotation.MetadataUtils.attributesFor;
-
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
@@ -31,13 +29,19 @@ import java.util.Set;
 import java.util.Stack;
 
 import org.springframework.beans.BeanUtils;
+import org.springframework.beans.factory.Aware;
+import org.springframework.beans.factory.BeanClassLoaderAware;
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.config.BeanDefinitionHolder;
+import org.springframework.beans.factory.config.ConfigurableBeanFactory;
 import org.springframework.beans.factory.parsing.Location;
 import org.springframework.beans.factory.parsing.Problem;
 import org.springframework.beans.factory.parsing.ProblemReporter;
 import org.springframework.beans.factory.support.BeanDefinitionReader;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.BeanNameGenerator;
+import org.springframework.context.ResourceLoaderAware;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.env.CompositePropertySource;
 import org.springframework.core.env.Environment;
@@ -52,6 +56,8 @@ import org.springframework.core.type.classreading.MetadataReaderFactory;
 import org.springframework.core.type.filter.AssignableTypeFilter;
 import org.springframework.util.StringUtils;
 
+import static org.springframework.context.annotation.MetadataUtils.*;
+
 /**
  * Parses a {@link Configuration} class definition, populating a collection of
  * {@link ConfigurationClass} objects (parsing a single Configuration class may result in
@@ -318,6 +324,7 @@ class ConfigurationClassParser {
 					// the candidate class is an ImportBeanDefinitionRegistrar -> delegate to it to register additional bean definitions
 					try {
 						ImportBeanDefinitionRegistrar registrar = BeanUtils.instantiateClass(Class.forName(candidate), ImportBeanDefinitionRegistrar.class);
+						invokeAwareMethods(registrar);
 						registrar.registerBeanDefinitions(importingClassMetadata, registry);
 					}
 					catch (ClassNotFoundException ex) {
@@ -334,6 +341,29 @@ class ConfigurationClassParser {
 		}
 	}
 
+	/**
+	 * Invoke {@link ResourceLoaderAware}, {@link BeanClassLoaderAware} and
+	 * {@link BeanFactoryAware} contracts if implemented by the given {@code registrar}.
+	 */
+	private void invokeAwareMethods(ImportBeanDefinitionRegistrar registrar) {
+		if (registrar instanceof Aware) {
+			if (registrar instanceof ResourceLoaderAware) {
+				((ResourceLoaderAware) registrar).setResourceLoader(resourceLoader);
+			}
+			if (registrar instanceof BeanClassLoaderAware) {
+				ClassLoader classLoader =
+						registry instanceof ConfigurableBeanFactory ?
+						((ConfigurableBeanFactory) registry).getBeanClassLoader() :
+						resourceLoader.getClassLoader();
+				((BeanClassLoaderAware) registrar).setBeanClassLoader(classLoader);
+			}
+			if (registrar instanceof BeanFactoryAware && registry instanceof BeanFactory) {
+				((BeanFactoryAware) registrar).setBeanFactory((BeanFactory) registry);
+			}
+		}
+	}
+
+
 	/**
 	 * Validate each {@link ConfigurationClass} object.
 	 * @see ConfigurationClass#validate
@@ -356,7 +386,6 @@ class ConfigurationClassParser {
 		return this.importStack;
 	}
 
-
 	interface ImportRegistry {
 
 		String getImportingClassFor(String importedClass);

spring-context/src/main/java/org/springframework/context/annotation/ImportBeanDefinitionRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -29,6 +29,15 @@ import org.springframework.core.type.AnnotationMetadata;
  * may be provided to the @{@link Import} annotation (or may also be returned from an
  * {@code ImportSelector}).
  *
+ * <p>An {@link ImportBeanDefinitionRegistrar} may implement any of the following
+ * {@link org.springframework.beans.factory.Aware Aware} interfaces, and their respective
+ * methods will be called prior to {@link #registerBeanDefinitions}:
+ * <ul>
+ * <li>{@link org.springframework.beans.factory.BeanFactoryAware BeanFactoryAware}
+ * <li>{@link org.springframework.beans.factory.BeanClassLoaderAware BeanClassLoaderAware}
+ * <li>{@link org.springframework.context.ResourceLoaderAware ResourceLoaderAware}
+ * </ul>
+ *
  * <p>See implementations and associated unit tests for usage examples.
  *
  * @author Chris Beams

spring-context/src/test/java/org/springframework/context/annotation/ImportBeanDefinitionRegistrarTests.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2002-2012 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.context.annotation;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.Assert.*;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.junit.Test;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.BeanClassLoaderAware;
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.BeanFactoryAware;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.context.MessageSource;
+import org.springframework.context.ResourceLoaderAware;
+import org.springframework.core.io.ResourceLoader;
+import org.springframework.core.type.AnnotationMetadata;
+
+/**
+ * Integration tests for {@link ImportBeanDefinitionRegistrar}.
+ *
+ * @author Oliver Gierke
+ * @author Chris Beams
+ */
+public class ImportBeanDefinitionRegistrarTests {
+
+	@Test
+	public void shouldInvokeAwareMethodsInImportBeanDefinitionRegistrar() {
+
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(Config.class);
+		context.getBean(MessageSource.class);
+
+		assertThat(SampleRegistrar.beanFactory, is((BeanFactory) context.getBeanFactory()));
+		assertThat(SampleRegistrar.classLoader, is(context.getBeanFactory().getBeanClassLoader()));
+		assertThat(SampleRegistrar.resourceLoader, is(notNullValue()));
+	}
+
+	@Sample
+	@Configuration
+	static class Config {
+
+	}
+
+	@Target(ElementType.TYPE)
+	@Retention(RetentionPolicy.RUNTIME)
+	@Import(SampleRegistrar.class)
+	public static @interface Sample {
+
+	}
+
+	static class SampleRegistrar implements ImportBeanDefinitionRegistrar, BeanClassLoaderAware, ResourceLoaderAware,
+			BeanFactoryAware {
+
+		static ClassLoader classLoader;
+		static ResourceLoader resourceLoader;
+		static BeanFactory beanFactory;
+
+		public void setBeanClassLoader(ClassLoader classLoader) {
+			SampleRegistrar.classLoader = classLoader;
+		}
+
+		public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
+			SampleRegistrar.beanFactory = beanFactory;
+		}
+
+		public void setResourceLoader(ResourceLoader resourceLoader) {
+			SampleRegistrar.resourceLoader = resourceLoader;
+		}
+
+		public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
+		}
+	}
+}