001/*
002 * Copyright 2002-2017 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.stereotype;
018
019import java.lang.annotation.Documented;
020import java.lang.annotation.ElementType;
021import java.lang.annotation.Retention;
022import java.lang.annotation.RetentionPolicy;
023import java.lang.annotation.Target;
024
025import org.springframework.core.annotation.AliasFor;
026
027/**
028 * Indicates that an annotated class is a "Controller" (e.g. a web controller).
029 *
030 * <p>This annotation serves as a specialization of {@link Component @Component},
031 * allowing for implementation classes to be autodetected through classpath scanning.
032 * It is typically used in combination with annotated handler methods based on the
033 * {@link org.springframework.web.bind.annotation.RequestMapping} annotation.
034 *
035 * @author Arjen Poutsma
036 * @author Juergen Hoeller
037 * @since 2.5
038 * @see Component
039 * @see org.springframework.web.bind.annotation.RequestMapping
040 * @see org.springframework.context.annotation.ClassPathBeanDefinitionScanner
041 */
042@Target({ElementType.TYPE})
043@Retention(RetentionPolicy.RUNTIME)
044@Documented
045@Component
046public @interface Controller {
047
048        /**
049         * The value may indicate a suggestion for a logical component name,
050         * to be turned into a Spring bean in case of an autodetected component.
051         * @return the suggested component name, if any (or empty String otherwise)
052         */
053        @AliasFor(annotation = Component.class)
054        String value() default "";
055
056}