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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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 if the package is unique in the environment.
52 * If running with modules, all modules in the modules graph are searched for matching packages.
53 *
54 * @param name fully qualified package name, or an empty string for an unnamed package
55 * @return the specified package, or {@code null} if it cannot be uniquely found
56 */
57 PackageElement getPackageElement(CharSequence name);
58
59 /**
60 * Returns a package given its fully qualified name, as seen from the given module.
61 *
62 * @param name fully qualified package name, or an empty string for an unnamed package
63 * @param module module relative to which the lookup should happen
64 * @return the specified package, or {@code null} if it cannot be found
65 * @since 9
66 */
67 PackageElement getPackageElement(ModuleElement module, CharSequence name);
68
69 /**
70 * Returns a type element given its canonical name if the type element is unique in the environment.
71 * If running with modules, all modules in the modules graph are searched for matching
72 * type elements.
73 *
74 * @param name the canonical name
75 * @return the named type element, or {@code null} if it cannot be uniquely found
76 */
77 TypeElement getTypeElement(CharSequence name);
78
79 /**
80 * Returns a type element given its canonical name, as seen from the given module.
81 *
82 * @param name the canonical name
83 * @param module module relative to which the lookup should happen
84 * @return the named type element, or {@code null} if it cannot be found
85 * @since 9
86 */
87 TypeElement getTypeElement(ModuleElement module, CharSequence name);
88
89 /**
90 * Returns a module element given its fully qualified name.
91 * If the named module cannot be found, null is returned. One situation where a module
92 * cannot be found is if the environment does not include modules, such as
93 * an annotation processing environment configured for
94 * a {@linkplain
95 * javax.annotation.processing.ProcessingEnvironment#getSourceVersion
96 * source version} without modules.
97 *
98 * @param name the name
99 * @return the named module element, or {@code null} if it cannot be found
100 * @since 9
101 * @spec JPMS
102 */
103 ModuleElement getModuleElement(CharSequence name);
104
105 /**
106 * Returns the values of an annotation's elements, including defaults.
107 *
108 * @see AnnotationMirror#getElementValues()
109 * @param a annotation to examine
110 * @return the values of the annotation's elements, including defaults
111 */
112 Map<? extends ExecutableElement, ? extends AnnotationValue>
113 getElementValuesWithDefaults(AnnotationMirror a);
114
115 /**
116 * Returns the text of the documentation ("Javadoc")
117 * comment of an element.
118 *
119 * <p> A documentation comment of an element is a comment that
120 * begins with "{@code /**}" , ends with a separate
121 * "<code>*/</code>", and immediately precedes the element,
122 * ignoring white space. Therefore, a documentation comment
123 * contains at least three"{@code *}" characters. The text
124 * returned for the documentation comment is a processed form of
125 * the comment as it appears in source code. The leading "{@code
126 * /**}" and trailing "<code>*/</code>" are removed. For lines
127 * of the comment starting after the initial "{@code /**}",
128 * leading white space characters are discarded as are any
129 * consecutive "{@code *}" characters appearing after the white
130 * space or starting the line. The processed lines are then
131 * concatenated together (including line terminators) and
132 * returned.
133 *
134 * @param e the element being examined
135 * @return the documentation comment of the element, or {@code null}
136 * if there is none
137 * @jls 3.6 White Space
138 */
139 String getDocComment(Element e);
140
141 /**
142 * Returns {@code true} if the element is deprecated, {@code false} otherwise.
143 *
144 * @param e the element being examined
145 * @return {@code true} if the element is deprecated, {@code false} otherwise
146 */
147 boolean isDeprecated(Element e);
148
149 /**
150 * Returns the <em>origin</em> of the given element.
151 *
152 * <p>Note that if this method returns {@link Origin#EXPLICIT
153 * EXPLICIT} and the element was created from a class file, then
154 * the element may not, in fact, correspond to an explicitly
155 * declared construct in source code. This is due to limitations
156 * of the fidelity of the class file format in preserving
157 * information from source code. For example, at least some
158 * versions of the class file format do not preserve whether a
159 * constructor was explicitly declared by the programmer or was
160 * implicitly declared as the <em>default constructor</em>.
161 *
162 * @implSpec The default implementation of this method returns
163 * {@link Origin#EXPLICIT EXPLICIT}.
164 *
165 * @param e the element being examined
166 * @return the origin of the given element
167 * @since 9
168 */
169 default Origin getOrigin(Element e) {
170 return Origin.EXPLICIT;
171 }
172
173 /**
174 * Returns the <em>origin</em> of the given annotation mirror.
175 *
176 * An annotation mirror is {@linkplain Origin#MANDATED mandated}
177 * if it is an implicitly declared <em>container annotation</em>
178 * used to hold repeated annotations of a repeatable annotation
179 * type.
180 *
181 * <p>Note that if this method returns {@link Origin#EXPLICIT
182 * EXPLICIT} and the annotation mirror was created from a class
183 * file, then the element may not, in fact, correspond to an
184 * explicitly declared construct in source code. This is due to
185 * limitations of the fidelity of the class file format in
186 * preserving information from source code. For example, at least
187 * some versions of the class file format do not preserve whether
188 * an annotation was explicitly declared by the programmer or was
189 * implicitly declared as a <em>container annotation</em>.
190 *
191 * @implSpec The default implementation of this method returns
192 * {@link Origin#EXPLICIT EXPLICIT}.
193 *
194 * @param c the construct the annotation mirror modifies
195 * @param a the annotation mirror being examined
196 * @return the origin of the given annotation mirror
197 * @jls 9.6.3 Repeatable Annotation Types
198 * @jls 9.7.5 Multiple Annotations of the Same Type
199 * @since 9
200 */
201 default Origin getOrigin(AnnotatedConstruct c,
202 AnnotationMirror a) {
203 return Origin.EXPLICIT;
204 }
205
206 /**
207 * Returns the <em>origin</em> of the given module directive.
208 *
209 * <p>Note that if this method returns {@link Origin#EXPLICIT
210 * EXPLICIT} and the module directive was created from a class
211 * file, then the module directive may not, in fact, correspond to
212 * an explicitly declared construct in source code. This is due to
213 * limitations of the fidelity of the class file format in
214 * preserving information from source code. For example, at least
215 * some versions of the class file format do not preserve whether
216 * a {@code uses} directive was explicitly declared by the
217 * programmer or was added as a synthetic construct.
218 *
219 * <p>Note that an implementation may not be able to reliably
220 * determine the origin status of the directive if the directive
221 * is created from a class file due to limitations of the fidelity
222 * of the class file format in preserving information from source
223 * code.
224 *
225 * @implSpec The default implementation of this method returns
226 * {@link Origin#EXPLICIT EXPLICIT}.
227 *
228 * @param m the module of the directive
229 * @param directive the module directive being examined
230 * @return the origin of the given directive
231 * @since 9
232 */
233 default Origin getOrigin(ModuleElement m,
234 ModuleElement.Directive directive) {
235 return Origin.EXPLICIT;
236 }
237
238 /**
239 * The <em>origin</em> of an element or other language model
240 * item. The origin of an element or item models how a construct
241 * in a program is declared in the source code, explicitly,
242 * implicitly, etc.
243 *
244 * <p>Note that it is possible additional kinds of origin values
245 * will be added in future versions of the platform.
246 *
247 * @jls 13.1 The Form of a Binary
248 * @since 9
249 */
250 public enum Origin {
251 /**
252 * Describes a construct explicitly declared in source code.
253 */
254 EXPLICIT,
255
256 /**
257 * A mandated construct is one that is not explicitly declared
258 * in the source code, but whose presence is mandated by the
259 * specification. Such a construct is said to be implicitly
260 * declared.
261 *
262 * One example of a mandated element is a <em>default
263 * constructor</em> in a class that contains no explicit
264 * constructor declarations.
265 *
266 * Another example of a mandated construct is an implicitly
267 * declared <em>container annotation</em> used to hold
268 * multiple annotations of a repeatable annotation type.
269 *
270 * @jls 8.8.9 Default Constructor
271 * @jls 9.6.3 Repeatable Annotation Types
272 * @jls 9.7.5 Multiple Annotations of the Same Type
273 */
274 MANDATED,
275
276 /**
277 * A synthetic construct is one that is neither implicitly nor
278 * explicitly declared in the source code. Such a construct is
279 * typically a translation artifact created by a compiler.
280 */
281 SYNTHETIC;
282
283 /**
284 * Returns {@code true} for values corresponding to constructs
285 * that are implicitly or explicitly declared, {@code false}
286 * otherwise.
287 * @return {@code true} for {@link EXPLICIT} and {@link
288 * MANDATED}, {@code false} otherwise.
289 */
290 public boolean isDeclared() {
291 return this != SYNTHETIC;
292 }
293 }
294
295 /**
296 * Returns {@code true} if the executable element is a bridge
297 * method, {@code false} otherwise.
298 *
299 * @implSpec The default implementation of this method returns {@code false}.
300 *
301 * @param e the executable being examined
302 * @return {@code true} if the executable element is a bridge
303 * method, {@code false} otherwise
304 * @since 9
305 */
306 default boolean isBridge(ExecutableElement e) {
307 return false;
308 }
309
310 /**
311 * Returns the <i>binary name</i> of a type element.
312 *
313 * @param type the type element being examined
314 * @return the binary name
315 *
316 * @see TypeElement#getQualifiedName
317 * @jls 13.1 The Form of a Binary
318 */
319 Name getBinaryName(TypeElement type);
320
321
322 /**
323 * Returns the package of an element. The package of a package is
324 * itself.
325 *
326 * @param type the element being examined
327 * @return the package of an element
328 */
329 PackageElement getPackageOf(Element type);
330
331 /**
332 * Returns the module of an element. The module of a module is
333 * itself.
334 * If there is no module for the element, null is returned. One situation where there is
335 * no module for an element is if the environment does not include modules, such as
336 * an annotation processing environment configured for
337 * a {@linkplain
338 * javax.annotation.processing.ProcessingEnvironment#getSourceVersion
339 * source version} without modules.
340 *
341 * @param type the element being examined
342 * @return the module of an element
343 * @since 9
344 * @spec JPMS
345 */
346 ModuleElement getModuleOf(Element type);
347
348 /**
349 * Returns all members of a type element, whether inherited or
350 * declared directly. For a class the result also includes its
351 * constructors, but not local or anonymous classes.
352 *
353 * <p>Note that elements of certain kinds can be isolated using
354 * methods in {@link ElementFilter}.
355 *
356 * @param type the type being examined
357 * @return all members of the type
358 * @see Element#getEnclosedElements
359 */
360 List<? extends Element> getAllMembers(TypeElement type);
361
362 /**
363 * Returns all annotations <i>present</i> on an element, whether
364 * directly present or present via inheritance.
365 *
366 * @param e the element being examined
367 * @return all annotations of the element
368 * @see Element#getAnnotationMirrors
369 * @see javax.lang.model.AnnotatedConstruct
370 */
371 List<? extends AnnotationMirror> getAllAnnotationMirrors(Element e);
372
373 /**
374 * Tests whether one type, method, or field hides another.
375 *
376 * @param hider the first element
377 * @param hidden the second element
378 * @return {@code true} if and only if the first element hides
379 * the second
380 */
381 boolean hides(Element hider, Element hidden);
382
383 /**
384 * Tests whether one method, as a member of a given type,
385 * overrides another method.
386 * When a non-abstract method overrides an abstract one, the
387 * former is also said to <i>implement</i> the latter.
388 *
389 * <p> In the simplest and most typical usage, the value of the
390 * {@code type} parameter will simply be the class or interface
391 * directly enclosing {@code overrider} (the possibly-overriding
392 * method). For example, suppose {@code m1} represents the method
393 * {@code String.hashCode} and {@code m2} represents {@code
394 * Object.hashCode}. We can then ask whether {@code m1} overrides
395 * {@code m2} within the class {@code String} (it does):
396 *
397 * <blockquote>
398 * {@code assert elements.overrides(m1, m2,
399 * elements.getTypeElement("java.lang.String")); }
400 * </blockquote>
401 *
402 * A more interesting case can be illustrated by the following example
403 * in which a method in type {@code A} does not override a
404 * like-named method in type {@code B}:
405 *
406 * <blockquote>
407 * {@code class A { public void m() {} } }<br>
408 * {@code interface B { void m(); } }<br>
409 * ...<br>
410 * {@code m1 = ...; // A.m }<br>
411 * {@code m2 = ...; // B.m }<br>
412 * {@code assert ! elements.overrides(m1, m2,
413 * elements.getTypeElement("A")); }
414 * </blockquote>
415 *
416 * When viewed as a member of a third type {@code C}, however,
417 * the method in {@code A} does override the one in {@code B}:
418 *
419 * <blockquote>
420 * {@code class C extends A implements B {} }<br>
421 * ...<br>
422 * {@code assert elements.overrides(m1, m2,
423 * elements.getTypeElement("C")); }
424 * </blockquote>
425 *
426 * @param overrider the first method, possible overrider
427 * @param overridden the second method, possibly being overridden
428 * @param type the type of which the first method is a member
429 * @return {@code true} if and only if the first method overrides
430 * the second
431 * @jls 8.4.8 Inheritance, Overriding, and Hiding
432 * @jls 9.4.1 Inheritance and Overriding
433 */
434 boolean overrides(ExecutableElement overrider, ExecutableElement overridden,
435 TypeElement type);
436
437 /**
438 * Returns the text of a <i>constant expression</i> representing a
439 * primitive value or a string.
440 * The text returned is in a form suitable for representing the value
441 * in source code.
442 *
443 * @param value a primitive value or string
444 * @return the text of a constant expression
445 * @throws IllegalArgumentException if the argument is not a primitive
446 * value or string
447 *
448 * @see VariableElement#getConstantValue()
449 */
450 String getConstantExpression(Object value);
451
452 /**
453 * Prints a representation of the elements to the given writer in
454 * the specified order. The main purpose of this method is for
455 * diagnostics. The exact format of the output is <em>not</em>
456 * specified and is subject to change.
457 *
458 * @param w the writer to print the output to
459 * @param elements the elements to print
460 */
461 void printElements(java.io.Writer w, Element... elements);
462
463 /**
464 * Return a name with the same sequence of characters as the
465 * argument.
466 *
467 * @param cs the character sequence to return as a name
468 * @return a name with the same sequence of characters as the argument
469 */
470 Name getName(CharSequence cs);
471
472 /**
473 * Returns {@code true} if the type element is a functional interface, {@code false} otherwise.
474 *
475 * @param type the type element being examined
476 * @return {@code true} if the element is a functional interface, {@code false} otherwise
477 * @jls 9.8 Functional Interfaces
478 * @since 1.8
479 */
480 boolean isFunctionalInterface(TypeElement type);
481 }