CODEWITHSUNDEEP
java
Reddi
Reddi

Reputation: 743

Java custom annotations takes another annotation

how can I write a custom annotation that takes another annotation and the values?

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface TestAnnotation{
  Class<? extends TestAnnotationChild> annotation();
}

The second annotation

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface TestAnnotationChild{

}

And I would like to do something like

@TestAnnotation(@TestAnnotationChild={values})

How can I do something like that?

Upvotes: 3

Views: 3020

Answers (3)

Samuel Philipp
Samuel Philipp

Reputation: 11050

You should just use TestAnnotationChild value(); instead of Class<? extends TestAnnotationChild> annotation();.

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface TestAnnotation{
  TestAnnotationChild value();
}

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface TestAnnotationChild {
    // String or whatever Object you want
    String[] value();
}

Now you can use the Annotations as you wanted:

@TestAnnotation(@TestAnnotationChild({"TEST"}))

Upvotes: 2

LppEdd
LppEdd

Reputation: 21172

This is how it is done.

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface TestAnnotation {
   TestAnnotationChild child();

   // Or for an array
   TestAnnotationChild[] children();
}

Usage

@TestAnnotation(
        @TestAnnotationChild(
               value = "42",
               anotherValue = 42
        )
)

However this part of your statement

and the values

does make me think you want to do something non-ordinary.
Could you clarify?

Upvotes: 4

L&#225;szl&#243; Stahorszki
L&#225;szl&#243; Stahorszki

Reputation: 1216

you can just have a property of type TestAnnotationChild in your TestAnnotation, just like it was a string, or whatever else

Upvotes: 0

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