Elements should be compared using the {@link #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 {@code * Element} object, either use a {@linkplain ElementVisitor visitor} or * use the result of the {@link #getKind} method. Using {@code * 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 {@code Element} subinterfaces. * * @author Joseph D. Darcy * @author Scott Seligman * @author Peter von der Ahé * @see Elements * @see TypeMirror * @since 1.6 */ public interface Element { /** * 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 {@code C To get inherited annotations as well, use
* {@link Elements#getAllAnnotationMirrors(Element) getAllAnnotationMirrors}.
*
* @see ElementFilter
*
* @return the annotations directly present on this element;
* an empty list if there are none
*/
List getAnnotationMirrors();
/**
* Returns this element's annotation for the specified type if
* such an annotation is present, else {@code 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 {@code 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 {@code Class} object by invoking the relevant
* method on the returned annotation
* will result in a {@link MirroredTypeException},
* from which the corresponding {@link TypeMirror} may be extracted.
* Similarly, attempting to read a {@code Class[]}-valued element
* will result in a {@link MirroredTypesException}.
*
* Note that elements of certain kinds can be isolated using
* methods in {@link ElementFilter}.
*
* @return the enclosed elements, or an empty list if none
* @see PackageElement#getEnclosedElements
* @see TypeElement#getEnclosedElements
* @see Elements#getAllMembers
* @jls 8.8.9 Default Constructor
* @jls 8.9 Enums
*/
List getEnclosedElements();
/**
* Returns {@code true} if the argument represents the same
* element as {@code this}, or {@code 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 {@code Class} objects for the same class file loaded through
* different class loaders.
*
* @param obj the object to be compared with this element
* @return {@code true} if the specified object represents the same
* element as this
*/
boolean equals(Object obj);
/**
* Obeys the general contract of {@link Object#hashCode Object.hashCode}.
*
* @see #equals
*/
int hashCode();
/**
* Applies a visitor to this element.
*
* @param the type of the additional parameter to the visitor's methods
* @param v the visitor operating on this element
* @param p additional parameter to the visitor
* @return a visitor-specified result
*/
* 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.
*
*
* @param the annotation type
* @param annotationType the {@code Class} object corresponding to
* the annotation type
* @return this element's annotation for the specified annotation
* type if present on this element, else {@code null}
*
* @see #getAnnotationMirrors()
* @see java.lang.reflect.AnnotatedElement#getAnnotation
* @see EnumConstantNotPresentException
* @see AnnotationTypeMismatchException
* @see IncompleteAnnotationException
* @see MirroredTypeException
* @see MirroredTypesException
*/
A getAnnotation(Class annotationType);
/**
* Returns the modifiers of this element, excluding annotations.
* Implicit modifiers, such as the {@code public} and {@code static}
* modifiers of interface members, are included.
*
* @return the modifiers of this element, or an empty set if there are none
*/
Set
*
*
* @return the enclosing element, or {@code null} if there is none
* @see Elements#getPackageOf
*/
Element getEnclosingElement();
/**
* Returns the elements that are, loosely speaking, directly
* enclosed by this element.
*
* A {@linkplain TypeElement#getEnclosedElements class or
* interface} is considered to enclose the fields, methods,
* constructors, and member types that it directly declares.
*
* A {@linkplain PackageElement#getEnclosedElements 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.
*
*