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 the <em>naturalness</em> of the given element.
141 *
142 * @implSpec The default implementation of this method returns
143 * {@link Naturalness#NATURAL NATURAL}.
144 *
145 * @param e the element being examined
146 * @return the naturalness of the given element
147 * @since 9
148 */
149 default Naturalness getNaturalness(Element e) {
150 return Naturalness.NATURAL;
151 }
152
153 /**
154 * Returns the <em>naturalness</em> of the given annotation mirror.
155 *
156 * One example of a mandated construct is the
157 * implicitly declared <em>container annotation</em> used to hold
158 * repeated base annotations of a repeatable annotation type.
159 *
160 * @implSpec The default implementation of this method returns
161 * {@link Naturalness#NATURAL NATURAL}.
162 *
163 * @param c the construct the annotation mirror modifies
164 * @param a the annotation mirror being examined
165 * @return the naturalness of the given annotation mirror
166 * @jls 9.6.3. Repeatable Annotation Types
167 * @jls 9.7.5 Multiple Annotations of the Same Type
168 * @since 9
169 */
170 default Naturalness getNaturalness(AnnotatedConstruct c, AnnotationMirror a) {
171 return Naturalness.NATURAL;
172 }
173
174 /**
175 * Returns the <em>naturalness</em> of the given module directive.
176 *
177 * @implSpec The default implementation of this method returns
178 * {@link Naturalness#NATURAL NATURAL}.
179 *
180 * @param m the module of the directive
181 * @param directive the module directive being examined
182 * @return the naturalness of the given directive
183 * @since 9
184 */
185 default Naturalness getNaturalness(ModuleElement m, ModuleElement.Directive directive) {
186 return Naturalness.NATURAL;
187 }
188
189 /**
190 * The <em>naturalness</em> of a construct. The naturalness of a
191 * construct concerns the consistency between how a construct is
192 * declared in source code (explicitly, implicitly, or not at all)
193 * compared to how the construct is represented in this model.
194 *
195 * Note that it is possible additional kinds of naturalness will
196 * be added in future versions of the platform.
197 *
198 * @jls 13.1. The Form of a Binary
199 * @since 9
200 */
201 enum Naturalness {
202 /**
203 * A natural construct is explicitly declared in source code.
204 */
205 NATURAL,
206
207 /**
208 * A mandated construct is not explicitly declared in the
209 * source code, but its presence is mandated by the
210 * specification to be implicitly declared.
211 *
212 * One example of a mandated construct is a <em>default
213 * constructor</em> in a class that contains no constructor
214 * declarations.
215 *
216 * Another example is the implicitly declared <em>container
217 * annotation</em> used to hold repeated base annotations of
218 * a repeatable annotation type.
219 *
220 * @jls 8.8.9 Default Constructor
221 * @jls 9.6.3. Repeatable Annotation Types
222 * @jls 9.7.5 Multiple Annotations of the Same Type
223 */
224 MANDATED,
225
226 /**
227 * A synthetic construct is one that is neither implicitly nor
228 * explicitly declared in source code. Synthetic constructs are
229 * commonly translation artifacts created by compiler.
230 */
231 SYNTHETIC;
232 }
233
234 /**
235 * Returns {@code true} if the executable element is a bridge
236 * method, {@code false} otherwise.
237 *
238 * @implSpec The default implementation of this method returns {@code false}.
239 *
240 * @param e the executable being examined
241 * @return {@code true} if the executable element is a bridge
242 * method, {@code false} otherwise
243 * @since 9
244 */
245 default boolean isBridge(ExecutableElement e) {
246 return false;
247 }
248
249 /**
250 * Returns the <i>binary name</i> of a type element.
251 *
252 * @param type the type element being examined
253 * @return the binary name
254 *
255 * @see TypeElement#getQualifiedName
256 * @jls 13.1 The Form of a Binary
257 */
258 Name getBinaryName(TypeElement type);
259
260
261 /**
262 * Returns the package of an element. The package of a package is
263 * itself.
264 *
265 * @param type the element being examined
266 * @return the package of an element
267 */
268 PackageElement getPackageOf(Element type);
269
270 /**
271 * Returns the module of an element. The module of a module is
272 * itself.
273 *
274 * @param type the element being examined
275 * @return the module of an element
276 * @since 9
277 */
278 ModuleElement getModuleOf(Element type);
279
280 /**
281 * Returns all members of a type element, whether inherited or
282 * declared directly. For a class the result also includes its
283 * constructors, but not local or anonymous classes.
284 *
285 * <p>Note that elements of certain kinds can be isolated using
286 * methods in {@link ElementFilter}.
287 *
288 * @param type the type being examined
289 * @return all members of the type
290 * @see Element#getEnclosedElements
291 */
292 List<? extends Element> getAllMembers(TypeElement type);
293
294 /**
295 * Returns all annotations <i>present</i> on an element, whether
296 * directly present or present via inheritance.
297 *
298 * @param e the element being examined
299 * @return all annotations of the element
300 * @see Element#getAnnotationMirrors
301 * @see javax.lang.model.AnnotatedConstruct
302 */
303 List<? extends AnnotationMirror> getAllAnnotationMirrors(Element e);
304
305 /**
306 * Tests whether one type, method, or field hides another.
307 *
308 * @param hider the first element
309 * @param hidden the second element
310 * @return {@code true} if and only if the first element hides
311 * the second
312 */
313 boolean hides(Element hider, Element hidden);
314
315 /**
316 * Tests whether one method, as a member of a given type,
317 * overrides another method.
318 * When a non-abstract method overrides an abstract one, the
319 * former is also said to <i>implement</i> the latter.
320 *
321 * <p> In the simplest and most typical usage, the value of the
322 * {@code type} parameter will simply be the class or interface
323 * directly enclosing {@code overrider} (the possibly-overriding
324 * method). For example, suppose {@code m1} represents the method
325 * {@code String.hashCode} and {@code m2} represents {@code
326 * Object.hashCode}. We can then ask whether {@code m1} overrides
327 * {@code m2} within the class {@code String} (it does):
328 *
329 * <blockquote>
330 * {@code assert elements.overrides(m1, m2,
331 * elements.getTypeElement("java.lang.String")); }
332 * </blockquote>
333 *
334 * A more interesting case can be illustrated by the following example
335 * in which a method in type {@code A} does not override a
336 * like-named method in type {@code B}:
337 *
338 * <blockquote>
339 * {@code class A { public void m() {} } }<br>
340 * {@code interface B { void m(); } }<br>
341 * ...<br>
342 * {@code m1 = ...; // A.m }<br>
343 * {@code m2 = ...; // B.m }<br>
344 * {@code assert ! elements.overrides(m1, m2,
345 * elements.getTypeElement("A")); }
346 * </blockquote>
347 *
348 * When viewed as a member of a third type {@code C}, however,
349 * the method in {@code A} does override the one in {@code B}:
350 *
351 * <blockquote>
352 * {@code class C extends A implements B {} }<br>
353 * ...<br>
354 * {@code assert elements.overrides(m1, m2,
355 * elements.getTypeElement("C")); }
356 * </blockquote>
357 *
358 * @param overrider the first method, possible overrider
359 * @param overridden the second method, possibly being overridden
360 * @param type the type of which the first method is a member
361 * @return {@code true} if and only if the first method overrides
362 * the second
363 * @jls 8.4.8 Inheritance, Overriding, and Hiding
364 * @jls 9.4.1 Inheritance and Overriding
365 */
366 boolean overrides(ExecutableElement overrider, ExecutableElement overridden,
367 TypeElement type);
368
369 /**
370 * Returns the text of a <i>constant expression</i> representing a
371 * primitive value or a string.
372 * The text returned is in a form suitable for representing the value
373 * in source code.
374 *
375 * @param value a primitive value or string
376 * @return the text of a constant expression
377 * @throws IllegalArgumentException if the argument is not a primitive
378 * value or string
379 *
380 * @see VariableElement#getConstantValue()
381 */
382 String getConstantExpression(Object value);
383
384 /**
385 * Prints a representation of the elements to the given writer in
386 * the specified order. The main purpose of this method is for
387 * diagnostics. The exact format of the output is <em>not</em>
388 * specified and is subject to change.
389 *
390 * @param w the writer to print the output to
391 * @param elements the elements to print
392 */
393 void printElements(java.io.Writer w, Element... elements);
394
395 /**
396 * Return a name with the same sequence of characters as the
397 * argument.
398 *
399 * @param cs the character sequence to return as a name
400 * @return a name with the same sequence of characters as the argument
401 */
402 Name getName(CharSequence cs);
403
404 /**
405 * Returns {@code true} if the type element is a functional interface, {@code false} otherwise.
406 *
407 * @param type the type element being examined
408 * @return {@code true} if the element is a functional interface, {@code false} otherwise
409 * @jls 9.8 Functional Interfaces
410 * @since 1.8
411 */
412 boolean isFunctionalInterface(TypeElement type);
413 }