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 "Repository", originally defined by
029 * Domain-Driven Design (Evans, 2003) as "a mechanism for encapsulating storage,
030 * retrieval, and search behavior which emulates a collection of objects".
031 *
032 * <p>Teams implementing traditional Java EE patterns such as "Data Access Object"
033 * may also apply this stereotype to DAO classes, though care should be taken to
034 * understand the distinction between Data Access Object and DDD-style repositories
035 * before doing so. This annotation is a general-purpose stereotype and individual teams
036 * may narrow their semantics and use as appropriate.
037 *
038 * <p>A class thus annotated is eligible for Spring
039 * {@link org.springframework.dao.DataAccessException DataAccessException} translation
040 * when used in conjunction with a {@link
041 * org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor
042 * PersistenceExceptionTranslationPostProcessor}. The annotated class is also clarified as
043 * to its role in the overall application architecture for the purpose of tooling,
044 * aspects, etc.
045 *
046 * <p>As of Spring 2.5, this annotation also serves as a specialization of
047 * {@link Component @Component}, allowing for implementation classes to be autodetected
048 * through classpath scanning.
049 *
050 * @author Rod Johnson
051 * @author Juergen Hoeller
052 * @since 2.0
053 * @see Component
054 * @see Service
055 * @see org.springframework.dao.DataAccessException
056 * @see org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor
057 */
058@Target({ElementType.TYPE})
059@Retention(RetentionPolicy.RUNTIME)
060@Documented
061@Component
062public @interface Repository {
063
064        /**
065         * The value may indicate a suggestion for a logical component name,
066         * to be turned into a Spring bean in case of an autodetected component.
067         * @return the suggested component name, if any (or empty String otherwise)
068         */
069        @AliasFor(annotation = Component.class)
070        String value() default "";
071
072}