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. This only holds true if @ConditionalOnClass is used on a class. Extra care must be taken when using @ConditionalOnClass on @Bean methods: the value attribute must not be used, instead the name attribute can be used to reference the class which must be present as a String. Alternatively create a separate @Configuration class that isolates 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 class 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. Using this attribute is safe when using ConditionalOnClass at class level, but it must not be used when using ConditionalOnClass on a @Bean method.

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 class names that must be present.

Returns:

the class names that must be present.

Default:

{}