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