org.springframework.boot.autoconfigure.condition

Annotation Type ConditionalOnBean

@Target(value={TYPE,METHOD})
 @Retention(value=RUNTIME)
 @Documented
 @Conditional(value=org.springframework.boot.autoconfigure.condition.OnBeanCondition.class)
public @interface ConditionalOnBean

Conditional that only matches when beans meeting all the specified requirements are already contained in the 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 @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 MyService is already contained in the 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.

Since:

1.0.0

Author:

Phillip Webb

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
Class<? extends Annotation>[]	annotation The annotation type decorating a bean that should be checked.
String[]	name The names of beans to check.
Class<?>[]	parameterizedContainer Additional classes that may contain the specified bean types within their generic parameters.
SearchStrategy	search Strategy to decide if the application context hierarchy (parent contexts) should be considered.
String[]	type The class type names of beans that should be checked.
Class<?>[]	value The class types of beans that should be checked.

Element Detail

value

public abstract Class<?>[] value

The class types of beans that should be checked. The condition matches when beans of all classes specified are contained in the BeanFactory.

Returns:

the class types of beans to check

Default:

{}

type

public abstract String[] type

The class type names of beans that should be checked. The condition matches when beans of all classes specified are contained in the BeanFactory.

Returns:

the class type names of beans to check

Default:

{}

annotation

public abstract Class<? extends Annotation>[] annotation

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 BeanFactory.

Returns:

the class-level annotation types to check

Default:

{}

name

public abstract String[] name

The names of beans to check. The condition matches when all of the bean names specified are contained in the BeanFactory.

Returns:

the names of beans to check

Default:

{}

search

public abstract SearchStrategy search

Strategy to decide if the application context hierarchy (parent contexts) should be considered.

Returns:

the search strategy

Default:

org.springframework.boot.autoconfigure.condition.SearchStrategy.ALL

parameterizedContainer

public abstract Class<?>[] parameterizedContainer

Additional classes that may contain the specified bean types within their generic parameters. For example, an annotation declaring value=Name.class and parameterizedContainer=NameRegistration.class would detect both Name and NameRegistration<Name>.

Returns:

the container types

Since:

2.1.0

Default:

{}