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 *
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
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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>origin</em> of the given element.
141 *
142 * <p>Note that if an element logically has a origin other
143 * than {@link Origin#EXPLICIT EXPLICIT}, an implementation may
144 * not be able to reliably determine this status if the element is
145 * created from a class file due to limitations of the fidelity of
146 * the class file format in preserving information from source
147 * code.
148 *
149 * @implSpec The default implementation of this method returns
150 * {@link Origin#EXPLICIT EXPLICIT}.
151 *
152 * @param e the element being examined
153 * @return the origin of the given element
154 * @since 9
155 */
156 default Origin getOrigin(Element e) {
157 return Origin.EXPLICIT;
158 }
159
160 /**
161 * Returns the <em>origin</em> of the given annotation mirror.
162 *
163 * An annotation mirror is {@linkplain Origin#MANDATED mandated}
164 * if it is an implicitly declared <em>container annotation</em>
165 * used to hold repeated base annotations of a repeatable
166 * annotation type.
167 *
168 * <p>Note that if an annotation mirror logically has a origin
169 * other than {@link Origin#EXPLICIT EXPLICIT}, an implementation
170 * may not be able to reliably determine this status if the
171 * annotation mirror is created from a class file due to
172 * limitations of the fidelity of the class file format in
173 * preserving information from source code.
174 *
175 * @implSpec The default implementation of this method returns
176 * {@link Origin#EXPLICIT EXPLICIT}.
177 *
178 * @param c the construct the annotation mirror modifies
179 * @param a the annotation mirror being examined
180 * @return the origin of the given annotation mirror
181 * @jls 9.6.3 Repeatable Annotation Types
182 * @jls 9.7.5 Multiple Annotations of the Same Type
183 * @since 9
184 */
185 default Origin getOrigin(AnnotatedConstruct c,
186 AnnotationMirror a) {
187 return Origin.EXPLICIT;
188 }
189
190 /**
191 * Returns the <em>origin</em> of the given module directive.
192 *
193 * <p>Note that if a directive logically has a origin other than
194 * {@link Origin#EXPLICIT EXPLICIT}, an implementation may not be
195 * able to reliably determine this status if the directive is
196 * created from a class file due to limitations of the fidelity of
197 * the class file format in preserving information from source
198 * code.
199 *
200 * @implSpec The default implementation of this method returns
201 * {@link Origin#EXPLICIT EXPLICIT}.
202 *
203 * @param m the module of the directive
204 * @param directive the module directive being examined
205 * @return the origin of the given directive
206 * @since 9
207 */
208 default Origin getOrigin(ModuleElement m,
209 ModuleElement.Directive directive) {
210 return Origin.EXPLICIT;
211 }
212
213 /**
214 * The <em>origin</em> of a construct. The origin of a construct
215 * concerns the consistency between how a construct is declared in
216 * source code (explicitly, implicitly, or not at all) compared to
217 * how the construct is represented in this model.
218 *
219 * <p>Note that it is possible additional kinds of origin values
220 * will be added in future versions of the platform.
221 *
222 * @jls 13.1 The Form of a Binary
223 * @since 9
224 */
225 enum Origin {
226 /**
227 * Describes a construct explicitly declared in source code.
228 */
229 EXPLICIT,
230
231 /**
232 * A mandated construct is one that is not explicitly declared
233 * in the source code, but whose presence is mandated by the
234 * specification. Such a construct is said to be implicitly
235 * declared.
236 *
237 * One example of a mandated element is a <em>default
238 * constructor</em> in a class that contains no explicit
239 * constructor declarations.
240 *
241 * Another example of a mandated construct is an implicitly
242 * declared <em>container annotation</em> used to hold
243 * multiple annotations of a repeatable annotation type.
244 *
245 * @jls 8.8.9 Default Constructor
246 * @jls 9.6.3 Repeatable Annotation Types
247 * @jls 9.7.5 Multiple Annotations of the Same Type
248 */
249 MANDATED,
250
251 /**
252 * A synthetic construct is one that is neither implicitly nor
253 * explicitly declared in the source code. Such a construct is
254 * typically a translation artifact created by a compiler.
255 */
256 SYNTHETIC;
257
258 /**
259 * Returns {@code true} for values corresponding to constructs
260 * that are implicitly or explicitly declared, {@code false}
261 * otherwise.
262 * @return {@code true} for {@link EXPLICIT} and {@link
263 * MANDATED}, {@code false} otherwise.
264 */
265 public boolean isDeclared() {
266 return this != SYNTHETIC;
267 }
268 }
269
270 /**
271 * Returns {@code true} if the executable element is a bridge
272 * method, {@code false} otherwise.
273 *
274 * @implSpec The default implementation of this method returns {@code false}.
275 *
276 * @param e the executable being examined
277 * @return {@code true} if the executable element is a bridge
278 * method, {@code false} otherwise
279 * @since 9
280 */
281 default boolean isBridge(ExecutableElement e) {
282 return false;
283 }
284
285 /**
286 * Returns the <i>binary name</i> of a type element.
287 *
288 * @param type the type element being examined
289 * @return the binary name
290 *
291 * @see TypeElement#getQualifiedName
292 * @jls 13.1 The Form of a Binary
293 */
294 Name getBinaryName(TypeElement type);
295
296
297 /**
298 * Returns the package of an element. The package of a package is
299 * itself.
300 *
301 * @param type the element being examined
302 * @return the package of an element
303 */
304 PackageElement getPackageOf(Element type);
305
306 /**
307 * Returns the module of an element. The module of a module is
308 * itself.
309 *
310 * @param type the element being examined
311 * @return the module of an element
312 * @since 9
313 */
314 ModuleElement getModuleOf(Element type);
315
316 /**
317 * Returns all members of a type element, whether inherited or
318 * declared directly. For a class the result also includes its
319 * constructors, but not local or anonymous classes.
320 *
321 * <p>Note that elements of certain kinds can be isolated using
322 * methods in {@link ElementFilter}.
323 *
324 * @param type the type being examined
325 * @return all members of the type
326 * @see Element#getEnclosedElements
327 */
328 List<? extends Element> getAllMembers(TypeElement type);
329
330 /**
331 * Returns all annotations <i>present</i> on an element, whether
332 * directly present or present via inheritance.
333 *
334 * @param e the element being examined
335 * @return all annotations of the element
336 * @see Element#getAnnotationMirrors
337 * @see javax.lang.model.AnnotatedConstruct
338 */
339 List<? extends AnnotationMirror> getAllAnnotationMirrors(Element e);
340
341 /**
342 * Tests whether one type, method, or field hides another.
343 *
344 * @param hider the first element
345 * @param hidden the second element
346 * @return {@code true} if and only if the first element hides
347 * the second
348 */
349 boolean hides(Element hider, Element hidden);
350
351 /**
352 * Tests whether one method, as a member of a given type,
353 * overrides another method.
354 * When a non-abstract method overrides an abstract one, the
355 * former is also said to <i>implement</i> the latter.
356 *
357 * <p> In the simplest and most typical usage, the value of the
358 * {@code type} parameter will simply be the class or interface
359 * directly enclosing {@code overrider} (the possibly-overriding
360 * method). For example, suppose {@code m1} represents the method
361 * {@code String.hashCode} and {@code m2} represents {@code
362 * Object.hashCode}. We can then ask whether {@code m1} overrides
363 * {@code m2} within the class {@code String} (it does):
364 *
365 * <blockquote>
366 * {@code assert elements.overrides(m1, m2,
367 * elements.getTypeElement("java.lang.String")); }
368 * </blockquote>
369 *
370 * A more interesting case can be illustrated by the following example
371 * in which a method in type {@code A} does not override a
372 * like-named method in type {@code B}:
373 *
374 * <blockquote>
375 * {@code class A { public void m() {} } }<br>
376 * {@code interface B { void m(); } }<br>
377 * ...<br>
378 * {@code m1 = ...; // A.m }<br>
379 * {@code m2 = ...; // B.m }<br>
380 * {@code assert ! elements.overrides(m1, m2,
381 * elements.getTypeElement("A")); }
382 * </blockquote>
383 *
384 * When viewed as a member of a third type {@code C}, however,
385 * the method in {@code A} does override the one in {@code B}:
386 *
387 * <blockquote>
388 * {@code class C extends A implements B {} }<br>
389 * ...<br>
390 * {@code assert elements.overrides(m1, m2,
391 * elements.getTypeElement("C")); }
392 * </blockquote>
393 *
394 * @param overrider the first method, possible overrider
395 * @param overridden the second method, possibly being overridden
396 * @param type the type of which the first method is a member
397 * @return {@code true} if and only if the first method overrides
398 * the second
399 * @jls 8.4.8 Inheritance, Overriding, and Hiding
400 * @jls 9.4.1 Inheritance and Overriding
401 */
402 boolean overrides(ExecutableElement overrider, ExecutableElement overridden,
403 TypeElement type);
404
405 /**
406 * Returns the text of a <i>constant expression</i> representing a
407 * primitive value or a string.
408 * The text returned is in a form suitable for representing the value
409 * in source code.
410 *
411 * @param value a primitive value or string
412 * @return the text of a constant expression
413 * @throws IllegalArgumentException if the argument is not a primitive
414 * value or string
415 *
416 * @see VariableElement#getConstantValue()
417 */
418 String getConstantExpression(Object value);
419
420 /**
421 * Prints a representation of the elements to the given writer in
422 * the specified order. The main purpose of this method is for
423 * diagnostics. The exact format of the output is <em>not</em>
424 * specified and is subject to change.
425 *
426 * @param w the writer to print the output to
427 * @param elements the elements to print
428 */
429 void printElements(java.io.Writer w, Element... elements);
430
431 /**
432 * Return a name with the same sequence of characters as the
433 * argument.
434 *
435 * @param cs the character sequence to return as a name
436 * @return a name with the same sequence of characters as the argument
437 */
438 Name getName(CharSequence cs);
439
440 /**
441 * Returns {@code true} if the type element is a functional interface, {@code false} otherwise.
442 *
443 * @param type the type element being examined
444 * @return {@code true} if the element is a functional interface, {@code false} otherwise
445 * @jls 9.8 Functional Interfaces
446 * @since 1.8
447 */
448 boolean isFunctionalInterface(TypeElement type);
449 }