CODEWITHSUNDEEP
javaspringaopspring-aop
Phate
Phate

Reputation: 6612

Is it possible to compose AOP annotations?

So, I have 2 annotation A and B coming from existing java libraries and that implement AOP.

Both of them do something that is necessary to my class and I need to put them in this order (A before B):

public class MyClass{

    @A(parameter="par")
    @B(value="key")
    public void method(){

    }
}

Would it be possible to define a 3rd annotation, C, as a composition of both? So in the end I would get:

public class MyClass{

    @C(parameter="par", value="key")
    public void method(){

    }
}

edit: added the requirement of taking a parameter from @A as well and the fact that I don't have the source code as the annotations are taken from libs.

Upvotes: 2

Views: 628

Answers (2)

Nonika
Nonika

Reputation: 2560

It depends on library you use. for example spring does 

 @Documented
   @Inherited
    @SpringBootConfiguration
    @EnableAutoConfiguration
    @ComponentScan(excludeFilters = {
            @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class),
            @Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) })
    public @interface SpringBootApplication {

        /**
         * Exclude specific auto-configuration classes such that they will never be applied.
         * @return the classes to exclude
         */
        @AliasFor(annotation = EnableAutoConfiguration.class)
        Class<?>[] exclude() default {};

with this approach you would have:

    @A
    @B
    public @interface C{
        @AliasFor(annotation = B.class)
        String value();
        @AliasFor(annotation = А.class, attribute = "parameter")
        String param();
    }

Upvotes: 1

reflexdemon
reflexdemon

Reputation: 902

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@A
@B
public @interface C {
    @AliasFor(annotation = B.class, attribute = "value")
    String value() default {};
}

Let me know if this works.

Upvotes: 1

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