org.springframework.boot.autoconfigure.condition.ConditionalOnBean Maven / Gradle / Ivy
/*
* Copyright 2012-2019 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.boot.autoconfigure.condition;
import java.lang.annotation.Annotation;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.annotation.Conditional;
/**
* {@link Conditional @Conditional} that only matches when beans meeting all the specified
* requirements are already contained in the {@link BeanFactory}. All the requirements
* must be met for the condition to match, but they do not have to be met by the same
* bean.
*
* When placed on a {@code @Bean} method, the bean class defaults to the return type of
* the factory method:
*
*
* @Configuration
* public class MyAutoConfiguration {
*
* @ConditionalOnBean
* @Bean
* public MyService myService() {
* ...
* }
*
* }
*
* In the sample above the condition will match if a bean of type {@code MyService} is
* already contained in the {@link BeanFactory}.
*
* The condition can only match the bean definitions that have been processed by the
* application context so far and, as such, it is strongly recommended to use this
* condition on auto-configuration classes only. If a candidate bean may be created by
* another auto-configuration, make sure that the one using this condition runs after.
*
* @author Phillip Webb
* @since 1.0.0
*/
@Target({ ElementType.TYPE, ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Conditional(OnBeanCondition.class)
public @interface ConditionalOnBean {
/**
* The class types of beans that should be checked. The condition matches when beans
* of all classes specified are contained in the {@link BeanFactory}.
* @return the class types of beans to check
*/
Class[] value() default {};
/**
* The class type names of beans that should be checked. The condition matches when
* beans of all classes specified are contained in the {@link BeanFactory}.
* @return the class type names of beans to check
*/
String[] type() default {};
/**
* The annotation type decorating a bean that should be checked. The condition matches
* when all of the annotations specified are defined on beans in the
* {@link BeanFactory}.
* @return the class-level annotation types to check
*/
Class[] annotation() default {};
/**
* The names of beans to check. The condition matches when all of the bean names
* specified are contained in the {@link BeanFactory}.
* @return the names of beans to check
*/
String[] name() default {};
/**
* Strategy to decide if the application context hierarchy (parent contexts) should be
* considered.
* @return the search strategy
*/
SearchStrategy search() default SearchStrategy.ALL;
/**
* Additional classes that may contain the specified bean types within their generic
* parameters. For example, an annotation declaring {@code value=Name.class} and
* {@code parameterizedContainer=NameRegistration.class} would detect both
* {@code Name} and {@code NameRegistration}.
* @return the container types
* @since 2.1.0
*/
Class[] parameterizedContainer() default {};
}