Module java.base

Enum ElementType

java.lang.Object
java.lang.Enum<ElementType>
java.lang.annotation.ElementType
All Implemented Interfaces:
Serializable, Comparable<ElementType>, Constable

public enum ElementType
extends Enum<ElementType>
The constants of this enumerated type provide a simple classification of the syntactic locations where annotations may appear in a Java program. These constants are used in Target meta-annotations to specify where it is legal to write annotations of a given type.

The syntactic locations where annotations may appear are split into declaration contexts, where annotations apply to declarations, and type contexts, where annotations apply to types used in declarations and expressions.

The constants ANNOTATION_TYPE, CONSTRUCTOR, FIELD, LOCAL_VARIABLE, METHOD, PACKAGE, MODULE, PARAMETER, TYPE, and TYPE_PARAMETER correspond to the declaration contexts in JLS 9.6.4.1.

For example, an annotation whose type is meta-annotated with @Target(ElementType.FIELD) may only be written as a modifier for a field declaration.

The constant TYPE_USE corresponds to the type contexts in JLS 4.11, as well as to two declaration contexts: type declarations (including annotation type declarations) and type parameter declarations.

For example, an annotation whose type is meta-annotated with @Target(ElementType.TYPE_USE) may be written on the type of a field (or within the type of the field, if it is a nested, parameterized, or array type), and may also appear as a modifier for, say, a class declaration.

The TYPE_USE constant includes type declarations and type parameter declarations as a convenience for designers of type checkers which give semantics to annotation types. For example, if the annotation type NonNull is meta-annotated with @Target(ElementType.TYPE_USE), then @NonNull class C {...} could be treated by a type checker as indicating that all variables of class C are non-null, while still allowing variables of other classes to be non-null or not non-null based on whether @NonNull appears at the variable's declaration.

See Java Language Specification:
9.6.4.1 @Target
4.1 The Kinds of Types and Values
Since:
1.5
  • Enum Constant Details

    • TYPE

      public static final ElementType TYPE
      Class, interface (including annotation type), enum, or record declaration
    • FIELD

      public static final ElementType FIELD
      Field declaration (includes enum constants)
    • METHOD

      public static final ElementType METHOD
      Method declaration
    • PARAMETER

      public static final ElementType PARAMETER
      Formal parameter declaration
    • CONSTRUCTOR

      public static final ElementType CONSTRUCTOR
      Constructor declaration
    • LOCAL_VARIABLE

      public static final ElementType LOCAL_VARIABLE
      Local variable declaration
    • ANNOTATION_TYPE

      public static final ElementType ANNOTATION_TYPE
      Annotation type declaration
    • PACKAGE

      public static final ElementType PACKAGE
      Package declaration
    • TYPE_PARAMETER

      public static final ElementType TYPE_PARAMETER
      Type parameter declaration
      Since:
      1.8
    • TYPE_USE

      public static final ElementType TYPE_USE
      Use of a type
      Since:
      1.8
    • MODULE

      public static final ElementType MODULE
      Module declaration.
      Since:
      9
    • RECORD_COMPONENT

      public static final ElementType RECORD_COMPONENT
      Record component
      See Java Language Specification:
      8.10.3 Record Members
      9.7.4 Where Annotations May Appear
      Since:
      16
  • Method Details

    • values

      public static ElementType[] values()
      Returns an array containing the constants of this enum type, in the order they are declared.
      Returns:
      an array containing the constants of this enum type, in the order they are declared
    • valueOf

      public static ElementType valueOf(String name)
      Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
      Parameters:
      name - the name of the enum constant to be returned.
      Returns:
      the enum constant with the specified name
      Throws:
      IllegalArgumentException - if this enum type has no constant with the specified name
      NullPointerException - if the argument is null