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/* * Copyright 2002-2016 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.context.annotation; import java.lang.annotation.Documented; import java.lang.annotation.ElementType; import java.lang.annotation.Repeatable; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; import org.springframework.beans.factory.support.BeanNameGenerator; import org.springframework.core.annotation.AliasFor; import org.springframework.core.type.filter.TypeFilter; /** * Configures component scanning directives for use with @{@link Configuration} classes. * Provides support parallel with Spring XML's {@code <context:component-scan>} element. * * <p>Either {@link #basePackageClasses} or {@link #basePackages} (or its alias * {@link #value}) may be specified to define specific packages to scan. If specific * packages are not defined, scanning will occur from the package of the * class that declares this annotation. * * <p>Note that the {@code <context:component-scan>} element has an * {@code annotation-config} attribute; however, this annotation does not. This is because * in almost all cases when using {@code @ComponentScan}, default annotation config * processing (e.g. processing {@code @Autowired} and friends) is assumed. Furthermore, * when using {@link AnnotationConfigApplicationContext}, annotation config processors are * always registered, meaning that any attempt to disable them at the * {@code @ComponentScan} level would be ignored. * * <p>See {@link Configuration @Configuration}'s Javadoc for usage examples. * * @author Chris Beams * @author Juergen Hoeller * @author Sam Brannen * @since 3.1 * @see Configuration */ @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.TYPE) @Documented @Repeatable(ComponentScans.class) public @interface ComponentScan { /** * Alias for {@link #basePackages}. * <p>Allows for more concise annotation declarations if no other attributes * are needed — for example, {@code @ComponentScan("org.my.pkg")} * instead of {@code @ComponentScan(basePackages = "org.my.pkg")}. */ @AliasFor("basePackages") String[] value() default {}; /** * Base packages to scan for annotated components. * <p>{@link #value} is an alias for (and mutually exclusive with) this * attribute. * <p>Use {@link #basePackageClasses} for a type-safe alternative to * String-based package names. */ @AliasFor("value") String[] basePackages() default {}; /** * Type-safe alternative to {@link #basePackages} for specifying the packages * to scan for annotated components. The package of each class specified will be scanned. * <p>Consider creating a special no-op marker class or interface in each package * that serves no purpose other than being referenced by this attribute. */ Class<?>[] basePackageClasses() default {}; /** * The {@link BeanNameGenerator} class to be used for naming detected components * within the Spring container. * <p>The default value of the {@link BeanNameGenerator} interface itself indicates * that the scanner used to process this {@code @ComponentScan} annotation should * use its inherited bean name generator, e.g. the default * {@link AnnotationBeanNameGenerator} or any custom instance supplied to the * application context at bootstrap time. * @see AnnotationConfigApplicationContext#setBeanNameGenerator(BeanNameGenerator) */ Class<? extends BeanNameGenerator> nameGenerator() default BeanNameGenerator.class; /** * The {@link ScopeMetadataResolver} to be used for resolving the scope of detected components. */ Class<? extends ScopeMetadataResolver> scopeResolver() default AnnotationScopeMetadataResolver.class; /** * Indicates whether proxies should be generated for detected components, which may be * necessary when using scopes in a proxy-style fashion. * <p>The default is defer to the default behavior of the component scanner used to * execute the actual scan. * <p>Note that setting this attribute overrides any value set for {@link #scopeResolver}. * @see ClassPathBeanDefinitionScanner#setScopedProxyMode(ScopedProxyMode) */ ScopedProxyMode scopedProxy() default ScopedProxyMode.DEFAULT; /** * Controls the class files eligible for component detection. * <p>Consider use of {@link #includeFilters} and {@link #excludeFilters} * for a more flexible approach. */ String resourcePattern() default ClassPathScanningCandidateComponentProvider.DEFAULT_RESOURCE_PATTERN; /** * Indicates whether automatic detection of classes annotated with {@code @Component} * {@code @Repository}, {@code @Service}, or {@code @Controller} should be enabled. */ boolean useDefaultFilters() default true; /** * Specifies which types are eligible for component scanning. * <p>Further narrows the set of candidate components from everything in {@link #basePackages} * to everything in the base packages that matches the given filter or filters. * <p>Note that these filters will be applied in addition to the default filters, if specified. * Any type under the specified base packages which matches a given filter will be included, * even if it does not match the default filters (i.e. is not annotated with {@code @Component}). * @see #resourcePattern() * @see #useDefaultFilters() */ Filter[] includeFilters() default {}; /** * Specifies which types are not eligible for component scanning. * @see #resourcePattern */ Filter[] excludeFilters() default {}; /** * Specify whether scanned beans should be registered for lazy initialization. * <p>Default is {@code false}; switch this to {@code true} when desired. * @since 4.1 */ boolean lazyInit() default false; /** * Declares the type filter to be used as an {@linkplain ComponentScan#includeFilters * include filter} or {@linkplain ComponentScan#excludeFilters exclude filter}. */ @Retention(RetentionPolicy.RUNTIME) @Target({}) @interface Filter { /** * The type of filter to use. * <p>Default is {@link FilterType#ANNOTATION}. * @see #classes * @see #pattern */ FilterType type() default FilterType.ANNOTATION; /** * Alias for {@link #classes}. * @see #classes */ @AliasFor("classes") Class<?>[] value() default {}; /** * The class or classes to use as the filter. * <p>The following table explains how the classes will be interpreted * based on the configured value of the {@link #type} attribute. * <table border="1"> * <tr><th>{@code FilterType}</th><th>Class Interpreted As</th></tr> * <tr><td>{@link FilterType#ANNOTATION ANNOTATION}</td> * <td>the annotation itself</td></tr> * <tr><td>{@link FilterType#ASSIGNABLE_TYPE ASSIGNABLE_TYPE}</td> * <td>the type that detected components should be assignable to</td></tr> * <tr><td>{@link FilterType#CUSTOM CUSTOM}</td> * <td>an implementation of {@link TypeFilter}</td></tr> * </table> * <p>When multiple classes are specified, <em>OR</em> logic is applied * — for example, "include types annotated with {@code @Foo} OR {@code @Bar}". * <p>Custom {@link TypeFilter TypeFilters} may optionally implement any of the * following {@link org.springframework.beans.factory.Aware Aware} interfaces, and * their respective methods will be called prior to {@link TypeFilter#match match}: * <ul> * <li>{@link org.springframework.context.EnvironmentAware EnvironmentAware}</li> * <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>Specifying zero classes is permitted but will have no effect on component * scanning. * @since 4.2 * @see #value * @see #type */ @AliasFor("value") Class<?>[] classes() default {}; /** * The pattern (or patterns) to use for the filter, as an alternative * to specifying a Class {@link #value}. * <p>If {@link #type} is set to {@link FilterType#ASPECTJ ASPECTJ}, * this is an AspectJ type pattern expression. If {@link #type} is * set to {@link FilterType#REGEX REGEX}, this is a regex pattern * for the fully-qualified class names to match. * @see #type * @see #classes */ String[] pattern() default {}; } }