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javax.lang.model.element
Interface Element

All Known Subinterfaces:
ExecutableElement, PackageElement, TypeElement, TypeParameterElement, VariableElement

public interface Element

Represents a program element such as a package, class, or method. Each element represents a static, language-level construct (and not, for example, a runtime construct of the virtual machine).

Elements should be compared using the equals(Object) method. There is no guarantee that any particular element will always be represented by the same object.

To implement operations based on the class of an Element object, either use a visitor or use the result of the getKind() method. Using instanceof is not necessarily a reliable idiom for determining the effective class of an object in this modeling hierarchy since an implementation may choose to have a single object implement multiple Element subinterfaces.

Since:
1.6
See Also:
Elements, TypeMirror

Method Summary
<R,P> R
accept(ElementVisitor<R,P> v, P p)
          Applies a visitor to this element.
 TypeMirror asType()
          Returns the type defined by this element.
 boolean equals(Object obj)
          Returns true if the argument represents the same element as this, or false otherwise.
<A extends Annotation>
A
getAnnotation(Class<A> annotationType)
          Returns this element's annotation for the specified type if such an annotation is present, else null.
 List<? extends AnnotationMirror> getAnnotationMirrors()
          Returns the annotations that are directly present on this element.
 List<? extends Element> getEnclosedElements()
          Returns the elements that are, loosely speaking, directly enclosed by this element.
 Element getEnclosingElement()
          Returns the innermost element within which this element is, loosely speaking, enclosed.
 ElementKind getKind()
          Returns the kind of this element.
 Set<Modifier> getModifiers()
          Returns the modifiers of this element, excluding annotations.
 Name getSimpleName()
          Returns the simple (unqualified) name of this element.
 int hashCode()
          Obeys the general contract of Object.hashCode.
 

Method Detail

asType

TypeMirror asType()
Returns the type defined by this element.

A generic element defines a family of types, not just one. If this is a generic element, a prototypical type is returned. This is the element's invocation on the type variables corresponding to its own formal type parameters. For example, for the generic class element C<N extends Number>, the parameterized type C<N> is returned. The Types utility interface has more general methods for obtaining the full range of types defined by an element.

Returns:
the type defined by this element
See Also:
Types

getKind

ElementKind getKind()
Returns the kind of this element.

Returns:
the kind of this element

getAnnotationMirrors

List<? extends AnnotationMirror> getAnnotationMirrors()
Returns the annotations that are directly present on this element.

To get inherited annotations as well, use getAllAnnotationMirrors.

Returns:
the annotations directly present on this element; an empty list if there are none
See Also:
ElementFilter

getAnnotation

<A extends Annotation> A getAnnotation(Class<A> annotationType)
Returns this element's annotation for the specified type if such an annotation is present, else null. The annotation may be either inherited or directly present on this element.

The annotation returned by this method could contain an element whose value is of type Class. This value cannot be returned directly: information necessary to locate and load a class (such as the class loader to use) is not available, and the class might not be loadable at all. Attempting to read a Class object by invoking the relevant method on the returned annotation will result in a MirroredTypeException, from which the corresponding TypeMirror may be extracted. Similarly, attempting to read a Class[]-valued element will result in a MirroredTypesException.

Note: This method is unlike others in this and related interfaces. It operates on runtime reflective information — representations of annotation types currently loaded into the VM — rather than on the representations defined by and used throughout these interfaces. Consequently, calling methods on the returned annotation object can throw many of the exceptions that can be thrown when calling methods on an annotation object returned by core reflection. This method is intended for callers that are written to operate on a known, fixed set of annotation types.

Type Parameters:
A - the annotation type
Parameters:
annotationType - the Class object corresponding to the annotation type
Returns:
this element's annotation for the specified annotation type if present on this element, else null
See Also:
getAnnotationMirrors(), AnnotatedElement.getAnnotation(java.lang.Class), EnumConstantNotPresentException, AnnotationTypeMismatchException, IncompleteAnnotationException, MirroredTypeException, MirroredTypesException

getModifiers

Set<Modifier> getModifiers()
Returns the modifiers of this element, excluding annotations. Implicit modifiers, such as the public and static modifiers of interface members, are included.

Returns:
the modifiers of this element, or an empty set if there are none

getSimpleName

Name getSimpleName()
Returns the simple (unqualified) name of this element. The name of a generic type does not include any reference to its formal type parameters. For example, the simple name of the type element java.util.Set<E> is "Set". If this element represents an unnamed package, an empty name is returned. If it represents a constructor, the name "<init>" is returned. If it represents a static initializer, the name "<clinit>" is returned. If it represents an anonymous class or instance initializer, an empty name is returned.

Returns:
the simple name of this element

getEnclosingElement

Element getEnclosingElement()
Returns the innermost element within which this element is, loosely speaking, enclosed.

Returns:
the enclosing element, or null if there is none
See Also:
Elements.getPackageOf(javax.lang.model.element.Element)

getEnclosedElements

List<? extends Element> getEnclosedElements()
Returns the elements that are, loosely speaking, directly enclosed by this element. A class or interface is considered to enclose the fields, methods, constructors, and member types that it directly declares. This includes any (implicit) default constructor and the implicit values and valueOf methods of an enum type. A package encloses the top-level classes and interfaces within it, but is not considered to enclose subpackages. Other kinds of elements are not currently considered to enclose any elements; however, that may change as this API or the programming language evolves.

Note that elements of certain kinds can be isolated using methods in ElementFilter.

Returns:
the enclosed elements, or an empty list if none
See Also:
Elements.getAllMembers(javax.lang.model.element.TypeElement)
jls3
8.8.9 Default Constructor, 8.9 Enums

equals

boolean equals(Object obj)
Returns true if the argument represents the same element as this, or false otherwise.

Note that the identity of an element involves implicit state not directly accessible from the element's methods, including state about the presence of unrelated types. Element objects created by different implementations of these interfaces should not be expected to be equal even if "the same" element is being modeled; this is analogous to the inequality of Class objects for the same class file loaded through different class loaders.

Overrides:
equals in class Object
Parameters:
obj - the object to be compared with this element
Returns:
true if the specified object represents the same element as this

hashCode

int hashCode()
Obeys the general contract of Object.hashCode.

Overrides:
hashCode in class Object
Returns:
a hash code value.
See Also:
equals(java.lang.Object)

accept

<R,P> R accept(ElementVisitor<R,P> v,
               P p)
Applies a visitor to this element.

Type Parameters:
R - the return type of the visitor's methods
P - the type of the additional parameter to the visitor's methods
Parameters:
v - the visitor operating on this element
p - additional parameter to the visitor
Returns:
a visitor-specified result

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