Enum Class 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 class 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 interface 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: class and interface declarations (including annotation declarations) and type parameter declarations.

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

The TYPE_USE constant includes class and interface declarations and type parameter declarations as a convenience for designers of type checkers which give semantics to annotation interfaces. For example, if the annotation interface 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

Nested classes/interfaces declared in class Enum

Enum.EnumDesc<E>

Modifier and Type	Class	Description
static final class	Enum.EnumDesc<E extends Enum<E>>	A nominal descriptor for an enum constant.

Enum Constant Summary

Enum Constants

Enum Constant	Description
ANNOTATION_TYPE	Annotation interface declaration (Formerly known as an annotation type.)
CONSTRUCTOR	Constructor declaration
FIELD	Field declaration (includes enum constants)
LOCAL_VARIABLE	Local variable declaration
METHOD	Method declaration
MODULE	Module declaration.
PACKAGE	Package declaration
PARAMETER	Formal parameter declaration
RECORD_COMPONENT	Record component
TYPE	Class, interface (including annotation interface), enum, or record declaration
TYPE_PARAMETER	Type parameter declaration
TYPE_USE	Use of a type

Method Summary

Modifier and Type	Method	Description
static ElementType	valueOf(String name)	Returns the enum constant of this class with the specified name.
static ElementType[]	values()	Returns an array containing the constants of this enum class, in the order they are declared.

Methods declared in class Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Modifier and Type	Method	Description
protected final Object	clone()	Throws CloneNotSupportedException.
final int	compareTo(ElementType o)	Compares this enum with the specified object for order.
final Optional<Enum.EnumDesc<ElementType>>	describeConstable()	Returns an enum descriptor EnumDesc for this instance, if one can be constructed, or an empty Optional if one cannot be.
final boolean	equals(Object other)	Returns true if the specified object is equal to this enum constant.
protected final void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. Finalization has been deprecated for removal.
final Class<ElementType>	getDeclaringClass()	Returns the Class object corresponding to this enum constant's enum type.
final int	hashCode()	Returns a hash code for this enum constant.
final String	name()	Returns the name of this enum constant, exactly as declared in its enum declaration.
final int	ordinal()	Returns the ordinal of this enumeration constant (its position in its enum declaration, where the initial constant is assigned an ordinal of zero).
String	toString()	Returns the name of this enum constant, as contained in the declaration.
static <T extends Enum<T>> T	valueOf(Class<T> enumClass, String name)	Returns the enum constant of the specified enum class with the specified name.

Methods declared in class Object

getClass, notify, notifyAll, wait, wait, wait

Modifier and Type	Method	Description
final Class<?>	getClass()	Returns the runtime class of this Object.
final void	notify()	Wakes up a single thread that is waiting on this object's monitor.
final void	notifyAll()	Wakes up all threads that are waiting on this object's monitor.
final void	wait()	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
final void	wait(long timeoutMillis)	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
final void	wait(long timeoutMillis, int nanos)	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Enum Constant Details

TYPE

public static final ElementType TYPE

Class, interface (including annotation interface), 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 interface declaration (Formerly known as an annotation type.)

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 class, in the order they are declared.

Returns:

an array containing the constants of this enum class, in the order they are declared

valueOf

public static ElementType valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (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 class has no constant with the specified name

NullPointerException - if the argument is null