package java.lang.annotation;

/**
 * Indicates the kinds of program element to which an annotation type is applicable. If a Target
 * meta-annotation is not present on an annotation type declaration, the declared type may be used
 * on any program element. If such a meta-annotation is present, the compiler will enforce the
 * specified usage restriction.
 *
 * For example, this meta-annotation indicates that the declared type is itself a meta-annotation
 * type. It can only be used on annotation type declarations:
 *
 * <pre>
 *    &#064;Target(ElementType.ANNOTATION_TYPE)
 *    public &#064;interface MetaAnnotationType {
 *        ...
 *    }
 * </pre>
 *
 * This meta-annotation indicates that the declared type is intended solely for use as a member type
 * in complex annotation type declarations. It cannot be used to annotate anything directly:
 *
 * <pre>
 *    &#064;Target({})
 *    public &#064;interface MemberType {
 *        ...
 *    }
 * </pre>
 *
 * It is a compile-time error for a single ElementType constant to appear more than once in a Target
 * annotation. For example, the following meta-annotation is illegal:
 *
 * <pre>
 *    &#064;Target({ElementType.FIELD, ElementType.METHOD, ElementType.FIELD})
 *    public &#064;interface Bogus {
 *        ...
 *    }
 * </pre>
 */
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.ANNOTATION_TYPE)
public @interface Target {

	/**
	 * Returns an array of the kinds of elements an annotation type can be applied
	 * to.
	 *
	 * @return an array of the kinds of elements an annotation type can be applied
	 *         to
	 */
	ElementType[] value();
}