org.springframework.boot.autoconfigure.condition

Annotation Type ConditionalOnClass

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

@Conditional that only matches when the specified classes are on the classpath.

A Class value can be safely specified on @Configuration classes as the annotation metadata is parsed by using ASM before the class is loaded. If a class reference cannot be used then a name String attribute can be used.

Note: Extra care must be taken when using @ConditionalOnClass on @Bean methods where typically the return type is the target of the condition. Before the condition on the method applies, the JVM will have loaded the class and potentially processed method references which will fail if the class is not present. To handle this scenario, a separate @Configuration class should be used to isolate the condition. For example:

 @Configuration(proxyBeanMethods = false)
 public class MyAutoConfiguration {

        @Configuration(proxyBeanMethods = false)
        @ConditionalOnClass(SomeService.class)
        public static class SomeServiceConfiguration {

                @Bean
                @ConditionalOnMissingBean
                public SomeService someService() {
                        return new SomeService();
                }

        }

 }

Since:

1.0.0

Author:

Phillip Webb

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
String[]	name The classes names that must be present.
Class<?>[]	value The classes that must be present.

Element Detail

value

public abstract Class<?>[] value

The classes that must be present. Since this annotation is parsed by loading class bytecode, it is safe to specify classes here that may ultimately not be on the classpath, only if this annotation is directly on the affected component and not if this annotation is used as a composed, meta-annotation. In order to use this annotation as a meta-annotation, only use the name() attribute.

Returns:

the classes that must be present

Default:

{}

name

public abstract String[] name

The classes names that must be present.

Returns:

the class names that must be present.

Default:

{}