Module java.compiler
Package javax.lang.model

# Interface AnnotatedConstruct

All Known Subinterfaces:
  `ArrayType`, `DeclaredType`, `Element`, `ErrorType`, `ExecutableElement`, `ExecutableType`, `IntersectionType`, `ModuleElement`, `NoType`, `NullType`, `PackageElement`, `Parameterizable`, `PrimitiveType`, `QualifiedNameable`, `RecordComponentElement`, `ReferenceType`, `TypeElement`, `TypeMirror`, `TypeParameterElement`, `TypeVariable`, `UnionType`, `VariableElement`, `WildcardType`

public interface AnnotatedConstruct
Represents a construct that can be annotated. A construct is either an element or a type. Annotations on an element are on a declaration, whereas annotations on a type are on a specific use of a type name. As defined by The Java Language Specification section 9.7.4, an annotation on an element is a declaration annotation and an annotation on a type is a type annotation. The terms directly present, present, indirectly present, and associated are used throughout this interface to describe precisely which annotations, either declaration annotations or type annotations, are returned by the methods in this interface.

In the definitions below, an annotation A has an annotation type AT. If AT is a repeatable annotation type, the type of the containing annotation is ATC.

Annotation A is directly present on a construct C if either:

- A is explicitly or implicitly declared as applying to the source code representation of C.

  Typically, if exactly one annotation of type AT appears in the source code of representation of C, then A is explicitly declared as applying to C. An annotation of type AT on a record component can be implicitly propagated down to affiliated mandated members. Type annotations modifying the type of a record component can be also propagated to mandated members. Propagation of the annotations to mandated members is governed by rules given in the The Java Language Specification. If there are multiple annotations of type AT present on C, then if AT is repeatable annotation type, an annotation of type ATC is implicitly declared on C.

- A representation of A appears in the executable output for C, such as the `RuntimeVisibleAnnotations` (JVMS 4.7.16) or `RuntimeVisibleParameterAnnotations` (JVMS 4.7.17) attributes of a class file.

An annotation A is present on a construct C if either:

- A is directly present on C.
- No annotation of type AT is directly present on C, and C is a class and AT is inheritable and A is present on the superclass of C.

An annotation A is indirectly present on a construct C if both:

- AT is a repeatable annotation type with a containing annotation type ATC.
- An annotation of type ATC is directly present on C and A is an annotation included in the result of calling the `value` method of the directly present annotation of type ATC.

An annotation A is associated with a construct C if either:

- A is directly or indirectly present on C.
- No annotation of type AT is directly or indirectly present on C, and C is a class, and AT is inheritable, and A is associated with the superclass of C.

See Java Language Specification:
  9.6 Annotation Interfaces
  9.6.4.3 `@Inherited`
  9.7.4 Where Annotations May Appear
  9.7.5 Multiple Annotations of the Same Interface
Since:
  1.8

- ## Method Summary

  Modifier and Type
  Method
  Description
  `<A extends Annotation>
  A`
  `getAnnotation(Class<A> annotationType)`
  Returns this construct's annotation of the specified type if such an annotation is present, else `null`.
  `List<? extends AnnotationMirror>`
  `getAnnotationMirrors()`
  Returns the annotations that are directly present on this construct.
  `<A extends Annotation>
  A[]`
  `getAnnotationsByType(Class<A> annotationType)`
  Returns annotations that are associated with this construct.

- ## Method Details

  - ### getAnnotationMirrors

    List<? extends AnnotationMirror> getAnnotationMirrors()
    Returns the annotations that are directly present on this construct.
    Returns:
      the annotations directly present on this construct; an empty list if there are none

  - ### getAnnotation

    <A extends Annotation> A getAnnotation(Class<A> annotationType)
    Returns this construct's annotation of the specified type if such an annotation is present, else `null`.

    The annotation returned by this method could contain an element whose value is of type `Class`. This value cannot be returned directly: information necessary to locate and load a class (such as the class loader to use) is not available, and the class might not be loadable at all. Attempting to read a `Class` object by invoking the relevant method on the returned annotation will result in a `MirroredTypeException`, from which the corresponding `TypeMirror` may be extracted. Similarly, attempting to read a `Class[]`-valued element will result in a `MirroredTypesException`.

    > Note: This method is unlike others in this and related interfaces. It operates on runtime reflective information — representations of annotation types currently loaded into the VM — rather than on the representations defined by and used throughout these interfaces. Consequently, calling methods on the returned annotation object can throw many of the exceptions that can be thrown when calling methods on an annotation object returned by core reflection. This method is intended for callers that are written to operate on a known, fixed set of annotation types.

    Type Parameters:
      `A` - the annotation type
    Parameters:
      `annotationType` - the `Class` object corresponding to the annotation type
    Returns:
      this construct's annotation of the specified type if such an annotation is present, else `null`
    See Java Language Specification:
      9.6.1 Annotation Interface Elements
    See Also:
      - `getAnnotationMirrors()`
      - `AnnotatedElement.getAnnotation(java.lang.Class<T>)`
      - `EnumConstantNotPresentException`
      - `AnnotationTypeMismatchException`
      - `IncompleteAnnotationException`
      - `MirroredTypeException`
      - `MirroredTypesException`

  - ### getAnnotationsByType

    <A extends Annotation> A[] getAnnotationsByType(Class<A> annotationType)
    Returns annotations that are associated with this construct. If there are no annotations associated with this construct, the return value is an array of length 0. The order of annotations which are directly or indirectly present on a construct C is computed as if indirectly present annotations on C are directly present on C in place of their container annotation, in the order in which they appear in the value element of the container annotation. The difference between this method and `getAnnotation(Class)` is that this method detects if its argument is a repeatable annotation type, and if so, attempts to find one or more annotations of that type by "looking through" a container annotation.

    The annotations returned by this method could contain an element whose value is of type `Class`. This value cannot be returned directly: information necessary to locate and load a class (such as the class loader to use) is not available, and the class might not be loadable at all. Attempting to read a `Class` object by invoking the relevant method on the returned annotation will result in a `MirroredTypeException`, from which the corresponding `TypeMirror` may be extracted. Similarly, attempting to read a `Class[]`-valued element will result in a `MirroredTypesException`.

    > Note: This method is unlike others in this and related interfaces. It operates on runtime reflective information — representations of annotation types currently loaded into the VM — rather than on the representations defined by and used throughout these interfaces. Consequently, calling methods on the returned annotation object can throw many of the exceptions that can be thrown when calling methods on an annotation object returned by core reflection. This method is intended for callers that are written to operate on a known, fixed set of annotation types.

    Type Parameters:
      `A` - the annotation type
    Parameters:
      `annotationType` - the `Class` object corresponding to the annotation type
    Returns:
      this construct's annotations for the specified annotation type if present on this construct, else an empty array
    See Java Language Specification:
      9.6 Annotation Interfaces
      9.6.1 Annotation Interface Elements
    See Also:
      - `getAnnotationMirrors()`
      - `getAnnotation(Class)`
      - `AnnotatedElement.getAnnotationsByType(Class)`
      - `EnumConstantNotPresentException`
      - `AnnotationTypeMismatchException`
      - `IncompleteAnnotationException`
      - `MirroredTypeException`
      - `MirroredTypesException`