Annotations for Enum Constants

[Anoop Krishnan]

I face a very strange problem
To explain it I use simple examples

I have an Annotation intValue as given below

    
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
 
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface intValue {
 int numericValue();
}

I want to use this Annotation for Enum constants as given below

    
public enum Numbers {
@intValue(numericValue = 1)
ONE,
@intValue(numericValue = 2)
TWO,
@intValue(numericValue = 3)
THREE;
}

Now I try to find the annotation via Reflection

 
Numbers.ONE.getDeclaringClass().isAnnotationPresent(intValue.class)   

isAnnotationPresent(intValue.class) always returns false
I tried the following

 
Numbers.ONE.getClass().isAnnotationPresent(intValue.class)   

but result is the same
Can you tell me what is wrong with this code.

[Rob Spoor]

No idea, but why not just use the ordinal() method each enumerated object inherits from java.lang.Enum?

[Ilja Preuss]

Or add a constructor to the enum...

[Bill Shirley]

Originally posted by Anoop Krishnan:
...

Numbers.ONE.getDeclaringClass().isAnnotationPresent(intValue.class)   

the annotation is not present on the class (enum Numbers)

 
Numbers.ONE.getClass().isAnnotationPresent(intValue.class)   

it's still not present on the class,


[B]

Numbers.class.getField("ONE").isAnnotationPresent(intValue.class)

should return true,
[/B]
[ January 03, 2008: Message edited by: Bill Shirley ]
[ January 03, 2008: Message edited by: Bill Shirley ]

[Anoop Krishnan]

Dear Friends

Thank you for your updates.

I am aware of the solutions which you suggested but my real problem is much more complex and I just explained it with a simple example

I want to find out why is it not possible to get the Annotation via reflection
I am sure that I am doing something wrong otherwise it should work.

Java doc for Annotation Target says ElementType.FIELD can be applied to Enum constants

[Rob Spoor]

Well Bill already gave you the answer. The annotation is not for the class, so of course you can't get it through the class. It is for the enum constants which are in fact special kinds of fields.

To make it a bit more generic:

String field = Numbers.ONE.toString();
Numbers.class.getField(field).isAnnotationPresent(intValue.class);

An enum constant's toString returns the name of the constant, so this code should work also for TWO and THREE.

[Anoop Krishnan]

Thank you Bill Shirley

It works now