How do you write an analogue of your Spring annotation in Groovy?

Question

Java

There is a Java code:

import org.springframework.stereotype.Component;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Component
public @interface TypeConverter {
}

How to rewrite it in Groovy? When transferring "in the forehead", I get the error "Annotation @org.springframework.stereotype.Component is not allowed on element ANNOTATION"

Answer 1

In short, everything is complicated.
Chapter 1
We look at the Component sorts:

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

  /**
   * The value may indicate a suggestion for a logical component name,
   * to be turned into a Spring bean in case of an autodetected component.
   * @return the suggested component name, if any
   */
  String value() default "";

}

We are interested in @Target(ElementType.TYPE) to find out what it means, take a look at JLS 8 #9.6.4.1
Type declarations: class, interface, enum, and annotation type declarations (§8.1.1, §9.1.1, §8.5, §9.5, §8.9, §9.6)
Corresponds to java.lang.annotation.ElementType.TYPE
Additionally, annotation type declarations correspond to java.lang.annotation.ElementType.ANNOTATION_TYPE
Additionally, the java docs say:
public static final ElementType TYPE
Class, interface (including annotation type), or enum declaration
So, you can use Component on the annotation, but groovyc thinks differently.
Chapter 2
Why do groove compilers think differently? Let's look for an answer to this question.
I did not find anything similar in the groove docks , so I decided to look in the dreary issue of the project's groove tracker - https://issues.apache.org/jira/browse/GROOVY.
I searched long and hard for some similar issue and found - GROOVY-7151 .
Who is too lazy to follow the link and read, I tell you: there is a problem, fixed in the compiler version 2.5.0-beta-1.
The latest release version is 2.4.6.
Chapter 3. What to do?
1. Be patient and wait for grooves 2.5
2. Don't use grooves
3. Do not use Component on annotations.