1 /*
2 * Copyright (c) 2005, 2016, 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 */
25
26 package javax.lang.model.util;
27
28
29 import java.util.List;
30 import java.util.Map;
31
32 import javax.lang.model.AnnotatedConstruct;
33 import javax.lang.model.element.*;
34
35
36 /**
37 * Utility methods for operating on program elements.
38 *
39 * <p><b>Compatibility Note:</b> Methods may be added to this interface
40 * in future releases of the platform.
41 *
42 * @author Joseph D. Darcy
43 * @author Scott Seligman
44 * @author Peter von der Ahé
45 * @see javax.annotation.processing.ProcessingEnvironment#getElementUtils
46 * @since 1.6
47 */
48 public interface Elements {
49
50 /**
51 * Returns a package given its fully qualified name.
52 *
53 * @param name fully qualified package name, or an empty string for an unnamed package
54 * @return the named package, or {@code null} if it cannot be found
55 */
56 PackageElement getPackageElement(CharSequence name);
57
58 /**
59 * Returns a package given its fully qualified name, as seen from the given module.
60 *
61 * @param name fully qualified package name, or an empty string for an unnamed package
62 * @param module module relative to which the lookup should happen
63 * @return the named package, or {@code null} if it cannot be found
64 * @since 9
65 */
66 PackageElement getPackageElement(ModuleElement module, CharSequence name);
67
68 /**
69 * Returns a type element given its canonical name.
70 *
71 * @param name the canonical name
72 * @return the named type element, or {@code null} if it cannot be found
73 */
74 TypeElement getTypeElement(CharSequence name);
75
76 /**
77 * Returns a type element given its canonical name, as seen from the given module.
78 *
79 * @param name the canonical name
80 * @param module module relative to which the lookup should happen
81 * @return the named type element, or {@code null} if it cannot be found
82 * @since 9
83 */
84 TypeElement getTypeElement(ModuleElement module, CharSequence name);
85
86 /**
87 * Returns a module element given its fully qualified name.
88 *
89 * @param name the name
90 * @return the named module element, or {@code null} if it cannot be found
91 * @since 9
92 */
93 ModuleElement getModuleElement(CharSequence name);
94
95 /**
96 * Returns the values of an annotation's elements, including defaults.
97 *
98 * @see AnnotationMirror#getElementValues()
99 * @param a annotation to examine
100 * @return the values of the annotation's elements, including defaults
101 */
102 Map<? extends ExecutableElement, ? extends AnnotationValue>
103 getElementValuesWithDefaults(AnnotationMirror a);
104
105 /**
106 * Returns the text of the documentation ("Javadoc")
107 * comment of an element.
108 *
109 * <p> A documentation comment of an element is a comment that
110 * begins with "{@code /**}" , ends with a separate
111 * "<code>*/</code>", and immediately precedes the element,
112 * ignoring white space. Therefore, a documentation comment
113 * contains at least three"{@code *}" characters. The text
114 * returned for the documentation comment is a processed form of
115 * the comment as it appears in source code. The leading "{@code
116 * /**}" and trailing "<code>*/</code>" are removed. For lines
117 * of the comment starting after the initial "{@code /**}",
118 * leading white space characters are discarded as are any
119 * consecutive "{@code *}" characters appearing after the white
120 * space or starting the line. The processed lines are then
121 * concatenated together (including line terminators) and
122 * returned.
123 *
124 * @param e the element being examined
125 * @return the documentation comment of the element, or {@code null}
126 * if there is none
127 * @jls 3.6 White Space
128 */
129 String getDocComment(Element e);
130
131 /**
132 * Returns {@code true} if the element is deprecated, {@code false} otherwise.
133 *
134 * @param e the element being examined
135 * @return {@code true} if the element is deprecated, {@code false} otherwise
136 */
137 boolean isDeprecated(Element e);
138
139 /**
140 * Returns {@code true} if the element is mandated, {@code false} otherwise.
141 *
142 * A mandated construct is not explicitly declared in the source
143 * code, but its presence is mandated by the specification to be
144 * implicitly declared. One example of a mandated construct is a
145 * <em>default constructor</em> in a class that contains no
146 * constructor declarations.
147 *
148 * @implSpec The default implementation of this method returns {@code false}.
149 *
150 * @param e the element being examined
151 * @return {@code true} if the element is mandated, {@code false} otherwise
152 * @jls 8.8.9 Default Constructor
153 * @jls 13.1. The Form of a Binary
154 * @since 9
155 */
156 default boolean isMandated(Element e) {
157 return false;
158 }
159
160 /**
161 * Returns {@code true} if the annotation mirror is mandated,
162 * {@code false} otherwise.
163 *
164 * A mandated construct is not explicitly declared in the source
165 * code, but its presence is mandated by the specification to be
166 * implicitly declared. One example of a mandated construct is the
167 * implicitly declared <em>container annotation</em> used to hold
168 * repeated base annotations of a repeatable annotation type.
169 *
170 * @implSpec The default implementation of this method returns {@code false}.
171 *
172
173 * @param c the construct the annotation mirror modifies
174 * @param a the annotation mirror being examined
175 * @return {@code true} if the element is mandated, {@code false} otherwise
176 * @jls 9.6.3. Repeatable Annotation Types
177 * @jls 9.7.5 Multiple Annotations of the Same Type
178 * @since 9
179 */
180 default boolean isMandated(AnnotatedConstruct c, AnnotationMirror a) {
181 return false;
182 }
183
184 /**
185 * Returns {@code true} if the element is synthetic, {@code false} otherwise.
186 *
187 * A synthetic element corresponds to a construct neither
188 * implicitly nor explicitly declared in source code.
189 *
190 * @implSpec The default implementation of this method returns {@code false}.
191 *
192 * @param e the element being examined
193 * @return {@code true} if the element is synthetic, {@code false} otherwise
194 * @jls 13.1. The Form of a Binary
195 * @since 9
196 */
197 default boolean isSynthetic(Element e) {
198 return false;
199 }
200
201 /**
202 * Returns the <i>binary name</i> of a type element.
203 *
204 * @param type the type element being examined
205 * @return the binary name
206 *
207 * @see TypeElement#getQualifiedName
208 * @jls 13.1 The Form of a Binary
209 */
210 Name getBinaryName(TypeElement type);
211
212
213 /**
214 * Returns the package of an element. The package of a package is
215 * itself.
216 *
217 * @param type the element being examined
218 * @return the package of an element
219 */
220 PackageElement getPackageOf(Element type);
221
222 /**
223 * Returns the module of an element. The module of a module is
224 * itself.
225 *
226 * @param type the element being examined
227 * @return the module of an element
228 * @since 9
229 */
230 ModuleElement getModuleOf(Element type);
231
232 /**
233 * Returns all members of a type element, whether inherited or
234 * declared directly. For a class the result also includes its
235 * constructors, but not local or anonymous classes.
236 *
237 * <p>Note that elements of certain kinds can be isolated using
238 * methods in {@link ElementFilter}.
239 *
240 * @param type the type being examined
241 * @return all members of the type
242 * @see Element#getEnclosedElements
243 */
244 List<? extends Element> getAllMembers(TypeElement type);
245
246 /**
247 * Returns all annotations <i>present</i> on an element, whether
248 * directly present or present via inheritance.
249 *
250 * @param e the element being examined
251 * @return all annotations of the element
252 * @see Element#getAnnotationMirrors
253 * @see javax.lang.model.AnnotatedConstruct
254 */
255 List<? extends AnnotationMirror> getAllAnnotationMirrors(Element e);
256
257 /**
258 * Tests whether one type, method, or field hides another.
259 *
260 * @param hider the first element
261 * @param hidden the second element
262 * @return {@code true} if and only if the first element hides
263 * the second
264 */
265 boolean hides(Element hider, Element hidden);
266
267 /**
268 * Tests whether one method, as a member of a given type,
269 * overrides another method.
270 * When a non-abstract method overrides an abstract one, the
271 * former is also said to <i>implement</i> the latter.
272 *
273 * <p> In the simplest and most typical usage, the value of the
274 * {@code type} parameter will simply be the class or interface
275 * directly enclosing {@code overrider} (the possibly-overriding
276 * method). For example, suppose {@code m1} represents the method
277 * {@code String.hashCode} and {@code m2} represents {@code
278 * Object.hashCode}. We can then ask whether {@code m1} overrides
279 * {@code m2} within the class {@code String} (it does):
280 *
281 * <blockquote>
282 * {@code assert elements.overrides(m1, m2,
283 * elements.getTypeElement("java.lang.String")); }
284 * </blockquote>
285 *
286 * A more interesting case can be illustrated by the following example
287 * in which a method in type {@code A} does not override a
288 * like-named method in type {@code B}:
289 *
290 * <blockquote>
291 * {@code class A { public void m() {} } }<br>
292 * {@code interface B { void m(); } }<br>
293 * ...<br>
294 * {@code m1 = ...; // A.m }<br>
295 * {@code m2 = ...; // B.m }<br>
296 * {@code assert ! elements.overrides(m1, m2,
297 * elements.getTypeElement("A")); }
298 * </blockquote>
299 *
300 * When viewed as a member of a third type {@code C}, however,
301 * the method in {@code A} does override the one in {@code B}:
302 *
303 * <blockquote>
304 * {@code class C extends A implements B {} }<br>
305 * ...<br>
306 * {@code assert elements.overrides(m1, m2,
307 * elements.getTypeElement("C")); }
308 * </blockquote>
309 *
310 * @param overrider the first method, possible overrider
311 * @param overridden the second method, possibly being overridden
312 * @param type the type of which the first method is a member
313 * @return {@code true} if and only if the first method overrides
314 * the second
315 * @jls 8.4.8 Inheritance, Overriding, and Hiding
316 * @jls 9.4.1 Inheritance and Overriding
317 */
318 boolean overrides(ExecutableElement overrider, ExecutableElement overridden,
319 TypeElement type);
320
321 /**
322 * Returns the text of a <i>constant expression</i> representing a
323 * primitive value or a string.
324 * The text returned is in a form suitable for representing the value
325 * in source code.
326 *
327 * @param value a primitive value or string
328 * @return the text of a constant expression
329 * @throws IllegalArgumentException if the argument is not a primitive
330 * value or string
331 *
332 * @see VariableElement#getConstantValue()
333 */
334 String getConstantExpression(Object value);
335
336 /**
337 * Prints a representation of the elements to the given writer in
338 * the specified order. The main purpose of this method is for
339 * diagnostics. The exact format of the output is <em>not</em>
340 * specified and is subject to change.
341 *
342 * @param w the writer to print the output to
343 * @param elements the elements to print
344 */
345 void printElements(java.io.Writer w, Element... elements);
346
347 /**
348 * Return a name with the same sequence of characters as the
349 * argument.
350 *
351 * @param cs the character sequence to return as a name
352 * @return a name with the same sequence of characters as the argument
353 */
354 Name getName(CharSequence cs);
355
356 /**
357 * Returns {@code true} if the type element is a functional interface, {@code false} otherwise.
358 *
359 * @param type the type element being examined
360 * @return {@code true} if the element is a functional interface, {@code false} otherwise
361 * @jls 9.8 Functional Interfaces
362 * @since 1.8
363 */
364 boolean isFunctionalInterface(TypeElement type);
365 }