Tue, 09 Oct 2012 19:10:00 -0700
8000663: clean up langtools imports
Reviewed-by: darcy
1 /*
2 * Copyright (c) 2005, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
26 package javax.lang.model.element;
29 import java.lang.annotation.Annotation;
30 import java.lang.annotation.AnnotationTypeMismatchException;
31 import java.lang.annotation.IncompleteAnnotationException;
32 import java.util.List;
33 import java.util.Set;
35 import javax.lang.model.type.*;
36 import javax.lang.model.util.*;
39 /**
40 * Represents a program element such as a package, class, or method.
41 * Each element represents a static, language-level construct
42 * (and not, for example, a runtime construct of the virtual machine).
43 *
44 * <p> Elements should be compared using the {@link #equals(Object)}
45 * method. There is no guarantee that any particular element will
46 * always be represented by the same object.
47 *
48 * <p> To implement operations based on the class of an {@code
49 * Element} object, either use a {@linkplain ElementVisitor visitor} or
50 * use the result of the {@link #getKind} method. Using {@code
51 * instanceof} is <em>not</em> necessarily a reliable idiom for
52 * determining the effective class of an object in this modeling
53 * hierarchy since an implementation may choose to have a single object
54 * implement multiple {@code Element} subinterfaces.
55 *
56 * @author Joseph D. Darcy
57 * @author Scott Seligman
58 * @author Peter von der Ahé
59 * @see Elements
60 * @see TypeMirror
61 * @since 1.6
62 */
63 public interface Element {
65 /**
66 * Returns the type defined by this element.
67 *
68 * <p> A generic element defines a family of types, not just one.
69 * If this is a generic element, a <i>prototypical</i> type is
70 * returned. This is the element's invocation on the
71 * type variables corresponding to its own formal type parameters.
72 * For example,
73 * for the generic class element {@code C<N extends Number>},
74 * the parameterized type {@code C<N>} is returned.
75 * The {@link Types} utility interface has more general methods
76 * for obtaining the full range of types defined by an element.
77 *
78 * @see Types
79 *
80 * @return the type defined by this element
81 */
82 TypeMirror asType();
84 /**
85 * Returns the {@code kind} of this element.
86 *
87 * @return the kind of this element
88 */
89 ElementKind getKind();
91 /**
92 * Returns the annotations that are directly present on this element.
93 *
94 * <p> To get inherited annotations as well, use
95 * {@link Elements#getAllAnnotationMirrors(Element) getAllAnnotationMirrors}.
96 *
97 * @see ElementFilter
98 *
99 * @return the annotations directly present on this element;
100 * an empty list if there are none
101 */
102 List<? extends AnnotationMirror> getAnnotationMirrors();
104 /**
105 * Returns this element's annotation for the specified type if
106 * such an annotation is present, else {@code null}. The
107 * annotation may be either inherited or directly present on this
108 * element.
109 *
110 * <p> The annotation returned by this method could contain an element
111 * whose value is of type {@code Class}.
112 * This value cannot be returned directly: information necessary to
113 * locate and load a class (such as the class loader to use) is
114 * not available, and the class might not be loadable at all.
115 * Attempting to read a {@code Class} object by invoking the relevant
116 * method on the returned annotation
117 * will result in a {@link MirroredTypeException},
118 * from which the corresponding {@link TypeMirror} may be extracted.
119 * Similarly, attempting to read a {@code Class[]}-valued element
120 * will result in a {@link MirroredTypesException}.
121 *
122 * <blockquote>
123 * <i>Note:</i> This method is unlike others in this and related
124 * interfaces. It operates on runtime reflective information —
125 * representations of annotation types currently loaded into the
126 * VM — rather than on the representations defined by and used
127 * throughout these interfaces. Consequently, calling methods on
128 * the returned annotation object can throw many of the exceptions
129 * that can be thrown when calling methods on an annotation object
130 * returned by core reflection. This method is intended for
131 * callers that are written to operate on a known, fixed set of
132 * annotation types.
133 * </blockquote>
134 *
135 * @param <A> the annotation type
136 * @param annotationType the {@code Class} object corresponding to
137 * the annotation type
138 * @return this element's annotation for the specified annotation
139 * type if present on this element, else {@code null}
140 *
141 * @see #getAnnotationMirrors()
142 * @see java.lang.reflect.AnnotatedElement#getAnnotation
143 * @see EnumConstantNotPresentException
144 * @see AnnotationTypeMismatchException
145 * @see IncompleteAnnotationException
146 * @see MirroredTypeException
147 * @see MirroredTypesException
148 */
149 <A extends Annotation> A getAnnotation(Class<A> annotationType);
151 /**
152 * Returns the modifiers of this element, excluding annotations.
153 * Implicit modifiers, such as the {@code public} and {@code static}
154 * modifiers of interface members, are included.
155 *
156 * @return the modifiers of this element, or an empty set if there are none
157 */
158 Set<Modifier> getModifiers();
160 /**
161 * Returns the simple (unqualified) name of this element. The
162 * name of a generic type does not include any reference to its
163 * formal type parameters.
164 *
165 * For example, the simple name of the type element {@code
166 * java.util.Set<E>} is {@code "Set"}.
167 *
168 * If this element represents an unnamed {@linkplain
169 * PackageElement#getSimpleName package}, an empty name is
170 * returned.
171 *
172 * If it represents a {@linkplain ExecutableElement#getSimpleName
173 * constructor}, the name "{@code <init>}" is returned. If it
174 * represents a {@linkplain ExecutableElement#getSimpleName static
175 * initializer}, the name "{@code <clinit>}" is returned.
176 *
177 * If it represents an {@linkplain TypeElement#getSimpleName
178 * anonymous class} or {@linkplain ExecutableElement#getSimpleName
179 * instance initializer}, an empty name is returned.
180 *
181 * @return the simple name of this element
182 */
183 Name getSimpleName();
185 /**
186 * Returns the innermost element
187 * within which this element is, loosely speaking, enclosed.
188 * <ul>
189 * <li> If this element is one whose declaration is lexically enclosed
190 * immediately within the declaration of another element, that other
191 * element is returned.
192 *
193 * <li> If this is a {@linkplain TypeElement#getEnclosingElement
194 * top-level type}, its package is returned.
195 *
196 * <li> If this is a {@linkplain
197 * PackageElement#getEnclosingElement package}, {@code null} is
198 * returned.
199 *
200 * <li> If this is a {@linkplain
201 * TypeParameterElement#getEnclosingElement type parameter},
202 * {@linkplain TypeParameterElement#getGenericElement the
203 * generic element} of the type parameter is returned.
204 *
205 * </ul>
206 *
207 * @return the enclosing element, or {@code null} if there is none
208 * @see Elements#getPackageOf
209 */
210 Element getEnclosingElement();
212 /**
213 * Returns the elements that are, loosely speaking, directly
214 * enclosed by this element.
215 *
216 * A {@linkplain TypeElement#getEnclosedElements class or
217 * interface} is considered to enclose the fields, methods,
218 * constructors, and member types that it directly declares.
219 *
220 * A {@linkplain PackageElement#getEnclosedElements package}
221 * encloses the top-level classes and interfaces within it, but is
222 * not considered to enclose subpackages.
223 *
224 * Other kinds of elements are not currently considered to enclose
225 * any elements; however, that may change as this API or the
226 * programming language evolves.
227 *
228 * <p>Note that elements of certain kinds can be isolated using
229 * methods in {@link ElementFilter}.
230 *
231 * @return the enclosed elements, or an empty list if none
232 * @see PackageElement#getEnclosedElements
233 * @see TypeElement#getEnclosedElements
234 * @see Elements#getAllMembers
235 * @jls 8.8.9 Default Constructor
236 * @jls 8.9 Enums
237 */
238 List<? extends Element> getEnclosedElements();
240 /**
241 * Returns {@code true} if the argument represents the same
242 * element as {@code this}, or {@code false} otherwise.
243 *
244 * <p>Note that the identity of an element involves implicit state
245 * not directly accessible from the element's methods, including
246 * state about the presence of unrelated types. Element objects
247 * created by different implementations of these interfaces should
248 * <i>not</i> be expected to be equal even if "the same"
249 * element is being modeled; this is analogous to the inequality
250 * of {@code Class} objects for the same class file loaded through
251 * different class loaders.
252 *
253 * @param obj the object to be compared with this element
254 * @return {@code true} if the specified object represents the same
255 * element as this
256 */
257 boolean equals(Object obj);
259 /**
260 * Obeys the general contract of {@link Object#hashCode Object.hashCode}.
261 *
262 * @see #equals
263 */
264 int hashCode();
266 /**
267 * Applies a visitor to this element.
268 *
269 * @param <R> the return type of the visitor's methods
270 * @param <P> the type of the additional parameter to the visitor's methods
271 * @param v the visitor operating on this element
272 * @param p additional parameter to the visitor
273 * @return a visitor-specified result
274 */
275 <R, P> R accept(ElementVisitor<R, P> v, P p);
276 }