ElementType

java.lang.Object
- java.lang.Enum<ElementType>
- - java.lang.annotation.ElementType

所有已实现的接口:

Serializable, Comparable<ElementType>
```
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 , 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.

从以下版本开始:

1.5

枚举常量概要

枚举常量
枚举常量	说明
`ANNOTATION_TYPE`	Annotation type declaration
`CONSTRUCTOR`	Constructor declaration
`FIELD`	Field declaration (includes enum constants)
`LOCAL_VARIABLE`	Local variable declaration
`METHOD`	Method declaration
`PACKAGE`	Package declaration
`PARAMETER`	Formal parameter declaration
`TYPE`	Class, interface (including annotation type), or enum declaration
`TYPE_PARAMETER`	Type parameter declaration
`TYPE_USE`	Use of a type

方法概要

所有方法静态方法具体方法
限定符和类型	方法	说明
`static ElementType`	`valueOf(String name)`	返回带有指定名称的该类型的枚举常量。字符串必须与用于声明该类型的枚举常量的标识符完全匹配。(不允许有多余的空格字符。)
`static ElementType[]`	`values()`	按照声明该枚举类型的常量的顺序, 返回包含这些常量的数组。该方法可用于迭代常量, 如下所示: for (ElementType c : ElementType.values()) System.out.println(c);

从类继承的方法 java.lang.Enum
clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

从类继承的方法 java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- 枚举常量详细资料
  - TYPE
```
public static final ElementType TYPE
```
    Class, interface (including annotation type), or enum 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
    
    从以下版本开始:
    
    1.8
  - TYPE_USE
```
public static final ElementType TYPE_USE
```
    Use of a type
    
    从以下版本开始:
    
    1.8
- 方法详细资料
  - values
```
public static ElementType[] values()
```
    按照声明该枚举类型的常量的顺序, 返回包含这些常量的数组。该方法可用于迭代常量, 如下所示:
```
for (ElementType c : ElementType.values())
    System.out.println(c);
```
    返回:
    
    按照声明该枚举类型的常量的顺序返回的包含这些常量的数组
  - valueOf
```
public static ElementType valueOf(String name)
```
    返回带有指定名称的该类型的枚举常量。字符串必须与用于声明该类型的枚举常量的标识符完全匹配。(不允许有多余的空格字符。)
    
    参数:
    
    name - 要返回的枚举常量的名称。
    
    返回:
    
    返回带有指定名称的枚举常量
    
    抛出:
    
    IllegalArgumentException - 如果该枚举类型没有带有指定名称的常量
    
    NullPointerException - 如果参数为空值

枚举 ElementType

枚举常量概要

方法概要

从类继承的方法 java.lang.Enum

从类继承的方法 java.lang.Object

枚举常量详细资料

TYPE

FIELD

METHOD

PARAMETER

CONSTRUCTOR

LOCAL_VARIABLE

ANNOTATION_TYPE

PACKAGE

TYPE_PARAMETER

TYPE_USE

方法详细资料

values

valueOf