- All Implemented Interfaces:
Serializable
,Comparable<ElementType>
,Constable
public enum ElementType extends Enum<ElementType>
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
-
Nested Class Summary
-
Enum Constant Summary
Enum Constants Enum Constant Description ANNOTATION_TYPE
Annotation type declarationCONSTRUCTOR
Constructor declarationFIELD
Field declaration (includes enum constants)LOCAL_VARIABLE
Local variable declarationMETHOD
Method declarationMODULE
Module declaration.PACKAGE
Package declarationPARAMETER
Formal parameter declarationRECORD_COMPONENT
Associated with records, a preview feature of the Java language.
Record componentTYPE
Class, interface (including annotation type), or enum declarationTYPE_PARAMETER
Type parameter declarationTYPE_USE
Use of a type -
Method Summary
Modifier and Type Method Description static ElementType
valueOf(String name)
Returns the enum constant of this type with the specified name.static ElementType[]
values()
Returns an array containing the constants of this enum type, in the order they are declared.
-
Enum Constant Details
-
TYPE
Class, interface (including annotation type), or enum declaration -
FIELD
Field declaration (includes enum constants) -
METHOD
Method declaration -
PARAMETER
Formal parameter declaration -
CONSTRUCTOR
Constructor declaration -
LOCAL_VARIABLE
Local variable declaration -
ANNOTATION_TYPE
Annotation type declaration -
PACKAGE
Package declaration -
TYPE_PARAMETER
Type parameter declaration- Since:
- 1.8
-
TYPE_USE
Use of a type- Since:
- 1.8
-
MODULE
Module declaration.- Since:
- 9
-
RECORD_COMPONENT
This constant is associated with records, a preview feature of the Java language. Programs can only use this constant when preview features are enabled. Preview features may be removed in a future release, or upgraded to permanent features of the Java language.
Record component- See Java Language Specification:
-
8.10.3 Record Members
9.7.4 Where Annotations May Appear - Since:
- 14
-
-
Method Details
-
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
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 nameNullPointerException
- if the argument is null
-