ElementType
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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 java.lang.annotation.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
,
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 15 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.
Inherited Method Summary
From class
java.lang.Enum
final
Object
|
clone()
Throws CloneNotSupportedException.
|
final
int
|
|
final
boolean
|
equals( Object other)
Returns true if the specified object is equal to this
enum constant.
|
final
void
|
finalize()
enum classes cannot have finalize methods.
|
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> enumType, String name)
Returns the enum constant of the specified enum type with the
specified name.
|
From class
java.lang.Object
Object
|
clone()
Creates and returns a copy of this Object .
|
boolean
|
equals( Object obj)
Compares this instance with the specified object and indicates if they
are equal.
|
void
|
finalize()
Invoked when the garbage collector has detected that this instance is no longer reachable.
|
final
Class<?>
|
getClass()
Returns the unique instance of Class that represents this
object's class.
|
int
|
hashCode()
Returns an integer hash code for this object.
|
final
void
|
notify()
Causes a thread which is waiting on this object's monitor (by means of
calling one of the wait() methods) to be woken up.
|
final
void
|
notifyAll()
Causes all threads which are waiting on this object's monitor (by means
of calling one of the wait() methods) to be woken up.
|
String
|
toString()
Returns a string containing a concise, human-readable description of this
object.
|
final
void
|
wait(long timeout, int nanos)
Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the
specified timeout expires.
|
final
void
|
wait(long timeout)
Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the
specified timeout expires.
|
final
void
|
wait()
Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.
|
Enum Values
public
static
final
ElementType
ANNOTATION_TYPE
Annotation type declaration
public
static
final
ElementType
CONSTRUCTOR
public
static
final
ElementType
FIELD
Field declaration (includes enum constants)
public
static
final
ElementType
LOCAL_VARIABLE
Local variable declaration
public
static
final
ElementType
METHOD
public
static
final
ElementType
PACKAGE
public
static
final
ElementType
PARAMETER
Formal parameter declaration
public
static
final
ElementType
TYPE
Class, interface (including annotation type), or enum declaration
public
static
final
ElementType
TYPE_PARAMETER
Type parameter declaration
public
static
final
ElementType
TYPE_USE
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Last updated 2024-07-10 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2024-07-10 UTC."],[[["`ElementType` is an enum that classifies where annotations can be placed in Java code."],["It differentiates between declaration contexts (e.g., class, method) and type contexts (e.g., field type)."],["`@Target` meta-annotation uses `ElementType` values to define valid locations for an annotation."],["`TYPE_USE` is a special constant covering type usages in declarations and expressions."],["The enum includes constants like `FIELD`, `METHOD`, `TYPE`, etc., representing specific code locations."]]],[]]