Provide dedicated @ComponentScan processing

@ComponentScan is now checked for explicitly and handled immediately
when parsing @Configuration classes.

org.springframework.context/src/main/java/org/springframework/context/annotation/ComponentScanAnnotationParser.java

+/*
+ * Copyright 2002-2011 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 java.lang.annotation.Annotation;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.beans.BeanUtils;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.beans.factory.support.BeanNameGenerator;
+import org.springframework.context.annotation.ComponentScan.Filter;
+import org.springframework.core.env.Environment;
+import org.springframework.core.io.ResourceLoader;
+import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.core.type.filter.AnnotationTypeFilter;
+import org.springframework.core.type.filter.AssignableTypeFilter;
+import org.springframework.core.type.filter.TypeFilter;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * Parser for the @{@link ComponentScan} annotation.
+ *
+ * @author Chris Beams
+ * @since 3.1
+ * @see ClassPathBeanDefinitionScanner#scan(String...)
+ * @see ComponentScanBeanDefinitionParser
+ */
+class ComponentScanAnnotationParser {
+
+	private final ResourceLoader resourceLoader;
+	private final Environment environment;
+	private final BeanDefinitionRegistry registry;
+
+	public ComponentScanAnnotationParser(ResourceLoader resourceLoader, Environment environment, BeanDefinitionRegistry registry) {
+		this.resourceLoader = resourceLoader;
+		this.environment = environment;
+		this.registry = registry;
+	}
+
+	public void parse(AnnotationMetadata annotationMetadata) {
+		Map<String, Object> attribs = annotationMetadata.getAnnotationAttributes(ComponentScan.class.getName());
+		if (attribs == null) {
+			// @ComponentScan annotation is not present -> do nothing
+			return;
+		}
+
+		ClassPathBeanDefinitionScanner scanner =
+			new ClassPathBeanDefinitionScanner(registry, (Boolean)attribs.get("useDefaultFilters"));
+
+		Assert.notNull(this.environment, "Environment must not be null");
+		scanner.setEnvironment(this.environment);
+
+		Assert.notNull(this.resourceLoader, "ResourceLoader must not be null");
+		scanner.setResourceLoader(this.resourceLoader);
+
+		scanner.setBeanNameGenerator(BeanUtils.instantiateClass(
+				(Class<?>)attribs.get("nameGenerator"), BeanNameGenerator.class));
+
+		ScopedProxyMode scopedProxyMode = (ScopedProxyMode) attribs.get("scopedProxy");
+		if (scopedProxyMode != ScopedProxyMode.DEFAULT) {
+			scanner.setScopedProxyMode(scopedProxyMode);
+		} else {
+			scanner.setScopeMetadataResolver(BeanUtils.instantiateClass(
+					(Class<?>)attribs.get("scopeResolver"), ScopeMetadataResolver.class));
+		}
+
+		scanner.setResourcePattern((String)attribs.get("resourcePattern"));
+
+		for (Filter filter : (Filter[])attribs.get("includeFilters")) {
+			scanner.addIncludeFilter(createTypeFilter(filter));
+		}
+		for (Filter filter : (Filter[])attribs.get("excludeFilters")) {
+			scanner.addExcludeFilter(createTypeFilter(filter));
+		}
+
+		List<String> basePackages = new ArrayList<String>();
+		for (String pkg : (String[])attribs.get("value")) {
+			if (StringUtils.hasText(pkg)) {
+				basePackages.add(pkg);
+			}
+		}
+		for (String pkg : (String[])attribs.get("basePackages")) {
+			if (StringUtils.hasText(pkg)) {
+				basePackages.add(pkg);
+			}
+		}
+		for (Class<?> clazz : (Class<?>[])attribs.get("basePackageClasses")) {
+			// TODO: loading user types directly here. implications on load-time
+			// weaving may mean we need to revert to stringified class names in
+			// annotation metadata
+			basePackages.add(clazz.getPackage().getName());
+		}
+
+		if (basePackages.isEmpty()) {
+			throw new IllegalStateException("At least one base package must be specified");
+		}
+
+		scanner.scan(basePackages.toArray(new String[]{}));
+	}
+
+	private TypeFilter createTypeFilter(Filter filter) {
+		switch (filter.type()) {
+			case ANNOTATION:
+				@SuppressWarnings("unchecked")
+				Class<Annotation> filterClass = (Class<Annotation>)filter.value();
+				return new AnnotationTypeFilter(filterClass);
+			case ASSIGNABLE_TYPE:
+				return new AssignableTypeFilter(filter.value());
+			case CUSTOM:
+				return BeanUtils.instantiateClass(filter.value(), TypeFilter.class);
+			default:
+				throw new IllegalArgumentException("unknown filter type " + filter.type());
+		}
+	}
+}

org.springframework.context/src/main/java/org/springframework/context/annotation/ConfigurationClassBeanDefinitionReader.java

@@ -95,6 +95,8 @@ public class ConfigurationClassBeanDefinitionReader {
 
 	private Environment environment;
 
+	private final ComponentScanAnnotationParser componentScanParser;
+
 	/**
 	 * Create a new {@link ConfigurationClassBeanDefinitionReader} instance that will be used
 	 * to populate the given {@link BeanDefinitionRegistry}.
@@ -111,6 +113,8 @@ public class ConfigurationClassBeanDefinitionReader {
 		this.metadataReaderFactory = metadataReaderFactory;
 		this.resourceLoader = resourceLoader;
 		this.environment = environment;
+
+		this.componentScanParser = new ComponentScanAnnotationParser(resourceLoader, environment, registry);
 	}
 
 
@@ -130,6 +134,7 @@ public class ConfigurationClassBeanDefinitionReader {
 	 */
 	private void loadBeanDefinitionsForConfigurationClass(ConfigurationClass configClass) {
 		AnnotationMetadata metadata = configClass.getMetadata();
+		componentScanParser.parse(metadata);
 		doLoadBeanDefinitionForConfigurationClassIfNecessary(configClass);
 		for (BeanMethod beanMethod : configClass.getBeanMethods()) {
 			loadBeanDefinitionsForBeanMethod(beanMethod);

org.springframework.context/src/test/java/org/springframework/context/annotation/ComponentScanAnnotationIntegrationTests.java

@@ -34,7 +34,6 @@ import org.springframework.aop.support.AopUtils;
 import org.springframework.beans.factory.annotation.CustomAutowireConfigurer;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.SimpleMapScope;
-import org.springframework.beans.factory.parsing.BeanDefinitionParsingException;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.context.annotation.ComponentScan.Filter;
@@ -114,7 +113,7 @@ public class ComponentScanAnnotationIntegrationTests {
 		try {
 			ctx.refresh();
 			fail("Expected exception when parsing @ComponentScan definition that declares no packages");
-		} catch (BeanDefinitionParsingException ex) {
+		} catch (IllegalStateException ex) {
 			assertThat(ex.getMessage(), containsString("At least one base package must be specified"));
 		}
 	}