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package java.lang.annotation;
/**
* Indicates the contexts in which an annotation interface is applicable. The
* declaration contexts and type contexts in which an annotation interface may
* be applicable are specified in JLS {@jls 9.6.4.1}, and denoted in source code by
* enum constants of {@link ElementType java.lang.annotation.ElementType}.
*
* If an {@code @Target} meta-annotation is not present on an annotation
* interface {@code T}, then an annotation of type {@code T} may be written as
* a modifier for any declaration.
*
*
If an {@code @Target} meta-annotation is present, the compiler will enforce
* the usage restrictions indicated by {@code ElementType}
* enum constants, in line with JLS {@jls 9.7.4}.
*
*
For example, this {@code @Target} meta-annotation indicates that the
* declared interface is itself a meta-annotation interface. It can only be
* used on annotation interface declarations:
*
* @Target(ElementType.ANNOTATION_TYPE)
* public @interface MetaAnnotationType {
* ...
* }
*
*
* This {@code @Target} meta-annotation indicates that the declared class or
* interface is intended solely for use as a member class or interface in
* complex annotation interface declarations. It cannot be used to annotate
* anything directly:
*
* @Target({})
* public @interface MemberInterface {
* ...
* }
*
*
* It is a compile-time error for a single {@code ElementType} constant to
* appear more than once in an {@code @Target} annotation. For example, the
* following {@code @Target} meta-annotation is illegal:
*
* @Target({ElementType.FIELD, ElementType.METHOD, ElementType.FIELD})
* public @interface Bogus {
* ...
* }
*
*
* @since 1.5
* @jls 9.6.4.1 @Target
* @jls 9.7.4 Where Annotations May Appear
* @jls 9.7.5 Multiple Annotations of the Same Interface
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.ANNOTATION_TYPE)
public @interface Target {
/**
* Returns an array of the kinds of elements an annotation interface
* can be applied to.
* @return an array of the kinds of elements an annotation interface
* can be applied to
*/
ElementType[] value();
}