Add @ImportAutoConfiguration annotation for tests

Add a new `@ImportAutoConfiguration` annotation that can be used by
tests that wish to selectively import certain auto-configuration
classes. Also add `@AutoConfigurationPackage` so that package
registration is decoupled from `@EnableAutoConfiguration`.

An added benefit of the change is @EnableAutoConfigurationImportSelector
can now be subclassed to provide custom annotation support if needed.

Fixes gh-3660
See gh-2772

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationPackage.java

+/*
+ * Copyright 2012-2015 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.boot.autoconfigure;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.context.annotation.Import;
+
+/**
+ * Indicates that the package containing the annotated class should be registered with
+ * {@link AutoConfigurationPackages}.
+ *
+ * @author Phillip Webb
+ * @since 1.3.0
+ * @see AutoConfigurationPackages
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@Inherited
+@Import(AutoConfigurationPackages.Registrar.class)
+public @interface AutoConfigurationPackage {
+
+}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/EnableAutoConfiguration.java

@@ -71,8 +71,8 @@ import org.springframework.core.io.support.SpringFactoriesLoader;
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
 @Inherited
-@Import({ EnableAutoConfigurationImportSelector.class,
-		AutoConfigurationPackages.Registrar.class })
+@AutoConfigurationPackage
+@Import(EnableAutoConfigurationImportSelector.class)
 public @interface EnableAutoConfiguration {
 
 	/**

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/EnableAutoConfigurationImportSelector.java

@@ -19,6 +19,7 @@ package org.springframework.boot.autoconfigure;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
@@ -41,18 +42,21 @@ import org.springframework.core.io.ResourceLoader;
 import org.springframework.core.io.support.SpringFactoriesLoader;
 import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 
 /**
  * {@link DeferredImportSelector} to handle {@link EnableAutoConfiguration
- * auto-configuration}.
+ * auto-configuration}. This class can also be subclassed if a custom variant of
+ * {@link EnableAutoConfiguration @EnableAutoConfiguration}. is needed.
  *
  * @author Phillip Webb
  * @author Andy Wilkinson
  * @author Stephane Nicoll
  * @see EnableAutoConfiguration
+ * @since 1.3.0
  */
 @Order(Ordered.LOWEST_PRECEDENCE - 1)
-class EnableAutoConfigurationImportSelector implements DeferredImportSelector,
+public class EnableAutoConfigurationImportSelector implements DeferredImportSelector,
 		BeanClassLoaderAware, ResourceLoaderAware, BeanFactoryAware, EnvironmentAware {
 
 	private ConfigurableListableBeanFactory beanFactory;
@@ -66,55 +70,113 @@ class EnableAutoConfigurationImportSelector implements DeferredImportSelector,
 	@Override
 	public String[] selectImports(AnnotationMetadata metadata) {
 		try {
-			AnnotationAttributes attributes = AnnotationAttributes.fromMap(metadata
-					.getAnnotationAttributes(EnableAutoConfiguration.class.getName(),
-							true));
-
-			Assert.notNull(attributes, "No auto-configuration attributes found. Is "
-					+ metadata.getClassName()
-					+ " annotated with @EnableAutoConfiguration?");
-
-			// Find all possible auto configuration classes, filtering duplicates
-			List<String> factories = new ArrayList<String>(new LinkedHashSet<String>(
-					SpringFactoriesLoader.loadFactoryNames(EnableAutoConfiguration.class,
-							this.beanClassLoader)));
-
-			// Remove those specifically excluded
-			Set<String> excluded = new LinkedHashSet<String>();
-			excluded.addAll(Arrays.asList(attributes.getStringArray("exclude")));
-			excluded.addAll(Arrays.asList(attributes.getStringArray("excludeName")));
-			excluded.addAll(getExcludeAutoConfigurationsProperty());
-			factories.removeAll(excluded);
-			ConditionEvaluationReport.get(this.beanFactory).recordExclusions(excluded);
-			ConditionEvaluationReport.get(this.beanFactory).recordEvaluationCandidates(
-					factories);
-
-			// Sort
-			factories = new AutoConfigurationSorter(this.resourceLoader)
-					.getInPriorityOrder(factories);
-
-			return factories.toArray(new String[factories.size()]);
+			AnnotationAttributes attributes = getAttributes(metadata);
+			List<String> configurations = getCandidateConfigurations(metadata, attributes);
+			configurations = removeDuplicates(configurations);
+			Set<String> exclusions = getExclusions(metadata, attributes);
+			configurations.removeAll(exclusions);
+			configurations = sort(configurations);
+			recordWithConditionEvaluationReport(configurations, exclusions);
+			return configurations.toArray(new String[configurations.size()]);
 		}
 		catch (IOException ex) {
 			throw new IllegalStateException(ex);
 		}
 	}
 
+	/**
+	 * Return the appropriate {@link AnnotationAttributes} from the
+	 * {@link AnnotationMetadata}. By default this method will return attributes for
+	 * {@link #getAnnotationClass()}.
+	 * @param metadata the annotation metadata
+	 * @return annotation attributes
+	 */
+	protected AnnotationAttributes getAttributes(AnnotationMetadata metadata) {
+		String name = getAnnotationClass().getName();
+		AnnotationAttributes attributes = AnnotationAttributes.fromMap(metadata
+				.getAnnotationAttributes(name, true));
+		Assert.notNull(attributes,
+				"No auto-configuration attributes found. Is " + metadata.getClassName()
+						+ " annotated with " + ClassUtils.getShortName(name) + "?");
+		return attributes;
+	}
+
+	/**
+	 * Return the source annotation class used by the selector.
+	 * @return the annotation class
+	 */
+	protected Class<?> getAnnotationClass() {
+		return EnableAutoConfiguration.class;
+	}
+
+	/**
+	 * Return the auto-configuration class names that should be considered. By default
+	 * this method will load candidates using {@link SpringFactoriesLoader} with
+	 * {@link #getSpringFactoriesLoaderFactoryClass()}.
+	 * @param metadata the source metadata
+	 * @param attributes the {@link #getAttributes(AnnotationMetadata) annotation
+	 * attributes}
+	 * @return a list of candidate configurations
+	 */
+	protected List<String> getCandidateConfigurations(AnnotationMetadata metadata,
+			AnnotationAttributes attributes) {
+		return SpringFactoriesLoader.loadFactoryNames(
+				getSpringFactoriesLoaderFactoryClass(), getBeanClassLoader());
+	}
+
+	/**
+	 * Return the class used by {@link SpringFactoriesLoader} to load configuration
+	 * candidates.
+	 * @return the factory class
+	 */
+	protected Class<?> getSpringFactoriesLoaderFactoryClass() {
+		return EnableAutoConfiguration.class;
+	}
+
+	/**
+	 * Return any exclusions that limit the candidate configurations.
+	 * @param metadata the source metadata
+	 * @param attributes the {@link #getAttributes(AnnotationMetadata) annotation
+	 * attributes}
+	 * @return exclusions or an empty set
+	 */
+	protected Set<String> getExclusions(AnnotationMetadata metadata,
+			AnnotationAttributes attributes) {
+		Set<String> excluded = new LinkedHashSet<String>();
+		excluded.addAll(asList(attributes, "exclude"));
+		excluded.addAll(Arrays.asList(attributes.getStringArray("excludeName")));
+		excluded.addAll(getExcludeAutoConfigurationsProperty());
+		return excluded;
+	}
+
 	private List<String> getExcludeAutoConfigurationsProperty() {
-		RelaxedPropertyResolver resolver = new RelaxedPropertyResolver(this.environment,
+		RelaxedPropertyResolver resolver = new RelaxedPropertyResolver(getEnvironment(),
 				"spring.autoconfigure.");
 		String[] exclude = resolver.getProperty("exclude", String[].class);
 		return (Arrays.asList(exclude == null ? new String[0] : exclude));
 	}
 
-	@Override
-	public void setBeanClassLoader(ClassLoader classLoader) {
-		this.beanClassLoader = classLoader;
+	private List<String> sort(List<String> configurations) throws IOException {
+		configurations = new AutoConfigurationSorter(getResourceLoader())
+				.getInPriorityOrder(configurations);
+		return configurations;
 	}
 
-	@Override
-	public void setResourceLoader(ResourceLoader resourceLoader) {
-		this.resourceLoader = resourceLoader;
+	private void recordWithConditionEvaluationReport(List<String> configurations,
+			Collection<String> exclusions) throws IOException {
+		ConditionEvaluationReport report = ConditionEvaluationReport
+				.get(getBeanFactory());
+		report.recordEvaluationCandidates(configurations);
+		report.recordExclusions(exclusions);
+	}
+
+	protected final <T> List<T> removeDuplicates(List<T> list) {
+		return new ArrayList<T>(new LinkedHashSet<T>(list));
+	}
+
+	protected final List<String> asList(AnnotationAttributes attributes, String name) {
+		String[] value = attributes.getStringArray(name);
+		return Arrays.asList(value == null ? new String[0] : value);
 	}
 
 	@Override
@@ -123,9 +185,35 @@ class EnableAutoConfigurationImportSelector implements DeferredImportSelector,
 		this.beanFactory = (ConfigurableListableBeanFactory) beanFactory;
 	}
 
+	protected final ConfigurableListableBeanFactory getBeanFactory() {
+		return this.beanFactory;
+	}
+
+	@Override
+	public void setBeanClassLoader(ClassLoader classLoader) {
+		this.beanClassLoader = classLoader;
+	}
+
+	protected ClassLoader getBeanClassLoader() {
+		return this.beanClassLoader;
+	}
+
 	@Override
 	public void setEnvironment(Environment environment) {
 		this.environment = environment;
 	}
 
+	protected final Environment getEnvironment() {
+		return this.environment;
+	}
+
+	@Override
+	public void setResourceLoader(ResourceLoader resourceLoader) {
+		this.resourceLoader = resourceLoader;
+	}
+
+	protected final ResourceLoader getResourceLoader() {
+		return this.resourceLoader;
+	}
+
 }

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/test/ImportAutoConfiguration.java

+/*
+ * Copyright 2012-2015 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.boot.autoconfigure.test;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.boot.autoconfigure.AutoConfigurationPackage;
+import org.springframework.context.annotation.Import;
+
+/**
+ * Import and apply the selected auto-configuration classes for testing purposes. Applies
+ * the same ordering rules as {@code @EnableAutoConfiguration} but restricts the
+ * auto-configuration classes to the specified set, rather than consulting
+ * {@code spring.factories}.
+ *
+ * @author Phillip Webb
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@Inherited
+@AutoConfigurationPackage
+@Import(ImportAutoConfigurationImportSelector.class)
+public @interface ImportAutoConfiguration {
+
+	/**
+	 * The auto-configuration classes that should be imported.
+	 * @return the classes to import
+	 */
+	Class<?>[] value();
+
+}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/test/ImportAutoConfigurationImportSelector.java

+/*
+ * Copyright 2012-2015 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.boot.autoconfigure.test;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Set;
+
+import org.springframework.boot.autoconfigure.EnableAutoConfigurationImportSelector;
+import org.springframework.core.annotation.AnnotationAttributes;
+import org.springframework.core.type.AnnotationMetadata;
+
+/**
+ * Variant of {@link EnableAutoConfigurationImportSelector} for
+ * {@link ImportAutoConfiguration}.
+ *
+ * @author Phillip Webb
+ */
+class ImportAutoConfigurationImportSelector extends EnableAutoConfigurationImportSelector {
+
+	@Override
+	protected Class<?> getAnnotationClass() {
+		return ImportAutoConfiguration.class;
+	}
+
+	@Override
+	protected Set<String> getExclusions(AnnotationMetadata metadata,
+			AnnotationAttributes attributes) {
+		return Collections.emptySet();
+	}
+
+	@Override
+	protected List<String> getCandidateConfigurations(AnnotationMetadata metadata,
+			AnnotationAttributes attributes) {
+		return asList(attributes, "value");
+	}
+
+}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/test/package-info.java

+/*
+ * Copyright 2012-2015 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.
+ */
+
+/**
+ * Test utilities related to auto-configuration.
+ */
+package org.springframework.boot.autoconfigure.test;
+

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/EnableAutoConfigurationImportSelectorTests.java

@@ -168,4 +168,5 @@ public class EnableAutoConfigurationImportSelectorTests {
 		return SpringFactoriesLoader.loadFactoryNames(EnableAutoConfiguration.class,
 				getClass().getClassLoader());
 	}
+
 }

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/context/ConfigurationPropertiesAutoConfigurationTests.java

@@ -18,9 +18,11 @@ package org.springframework.boot.autoconfigure.context;
 
 import org.junit.After;
 import org.junit.Test;
+import org.springframework.boot.autoconfigure.test.ImportAutoConfiguration;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.boot.test.EnvironmentTestUtils;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.stereotype.Component;
 
 import static org.hamcrest.core.Is.is;
@@ -44,8 +46,7 @@ public class ConfigurationPropertiesAutoConfigurationTests {
 
 	@Test
 	public void processAnnotatedBean() {
-		load(new Class[] { SampleBean.class,
-				ConfigurationPropertiesAutoConfiguration.class }, "foo.name:test");
+		load(new Class[] { AutoConfig.class, SampleBean.class }, "foo.name:test");
 		assertThat(this.context.getBean(SampleBean.class).getName(), is("test"));
 	}
 
@@ -62,6 +63,12 @@ public class ConfigurationPropertiesAutoConfigurationTests {
 		this.context.refresh();
 	}
 
+	@Configuration
+	@ImportAutoConfiguration(ConfigurationPropertiesAutoConfiguration.class)
+	static class AutoConfig {
+
+	}
+
 	@Component
 	@ConfigurationProperties("foo")
 	static class SampleBean {

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/test/ImportAutoConfigurationImportSelectorTests.java

+/*
+ * Copyright 2012-2015 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.boot.autoconfigure.test;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration;
+import org.springframework.core.annotation.AnnotationAttributes;
+import org.springframework.core.env.Environment;
+import org.springframework.core.io.DefaultResourceLoader;
+import org.springframework.core.type.AnnotationMetadata;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.verifyZeroInteractions;
+
+/**
+ * Tests for {@link ImportAutoConfigurationImportSelector}.
+ *
+ * @author Phillip Webb
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class ImportAutoConfigurationImportSelectorTests {
+
+	private final ImportAutoConfigurationImportSelector importSelector = new ImportAutoConfigurationImportSelector();
+
+	private final ConfigurableListableBeanFactory beanFactory = new DefaultListableBeanFactory();
+
+	@Mock
+	private Environment environment;
+
+	@Mock
+	private AnnotationMetadata annotationMetadata;
+
+	@Mock
+	private AnnotationAttributes annotationAttributes;
+
+	@Before
+	public void configureImportSelector() {
+		this.importSelector.setBeanFactory(this.beanFactory);
+		this.importSelector.setEnvironment(this.environment);
+		this.importSelector.setResourceLoader(new DefaultResourceLoader());
+	}
+
+	@Test
+	public void importsAreSelected() {
+		String[] value = new String[] { FreeMarkerAutoConfiguration.class.getName() };
+		configureValue(value);
+		String[] imports = this.importSelector.selectImports(this.annotationMetadata);
+		assertThat(imports, equalTo(value));
+	}
+
+	@Test
+	public void propertyExclusionsAreNotApplied() {
+		configureValue(new String[] { FreeMarkerAutoConfiguration.class.getName() });
+		this.importSelector.selectImports(this.annotationMetadata);
+		verifyZeroInteractions(this.environment);
+	}
+
+	private void configureValue(String... value) {
+		String name = ImportAutoConfiguration.class.getName();
+		given(this.annotationMetadata.getAnnotationAttributes(name, true)).willReturn(
+				this.annotationAttributes);
+		given(this.annotationAttributes.getStringArray("value")).willReturn(value);
+	}
+
+}