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 {@code true} if the executable element is a bridge 203 * method, {@code false} otherwise. 204 * 205 * @implSpec The default implementation of this method returns {@code false}. 206 * 207 * @param e the executable being examined 208 * @return {@code true} if the executable element is a bridge 209 * method, {@code false} otherwise 210 * @since 9 211 */ 212 default boolean isBridge(ExecutableElement e) { 213 return false; 214 } 215 216 /** 217 * Returns the <i>binary name</i> of a type element. 218 * 219 * @param type the type element being examined 220 * @return the binary name 221 * 222 * @see TypeElement#getQualifiedName 223 * @jls 13.1 The Form of a Binary 224 */ 225 Name getBinaryName(TypeElement type); 226 227 228 /** 229 * Returns the package of an element. The package of a package is 230 * itself. 231 * 232 * @param type the element being examined 233 * @return the package of an element 234 */ 235 PackageElement getPackageOf(Element type); 236 237 /** 238 * Returns the module of an element. The module of a module is 239 * itself. 240 * 241 * @param type the element being examined 242 * @return the module of an element 243 * @since 9 244 */ 245 ModuleElement getModuleOf(Element type); 246 247 /** 248 * Returns all members of a type element, whether inherited or 249 * declared directly. For a class the result also includes its 250 * constructors, but not local or anonymous classes. 251 * 252 * <p>Note that elements of certain kinds can be isolated using 253 * methods in {@link ElementFilter}. 254 * 255 * @param type the type being examined 256 * @return all members of the type 257 * @see Element#getEnclosedElements 258 */ 259 List<? extends Element> getAllMembers(TypeElement type); 260 261 /** 262 * Returns all annotations <i>present</i> on an element, whether 263 * directly present or present via inheritance. 264 * 265 * @param e the element being examined 266 * @return all annotations of the element 267 * @see Element#getAnnotationMirrors 268 * @see javax.lang.model.AnnotatedConstruct 269 */ 270 List<? extends AnnotationMirror> getAllAnnotationMirrors(Element e); 271 272 /** 273 * Tests whether one type, method, or field hides another. 274 * 275 * @param hider the first element 276 * @param hidden the second element 277 * @return {@code true} if and only if the first element hides 278 * the second 279 */ 280 boolean hides(Element hider, Element hidden); 281 282 /** 283 * Tests whether one method, as a member of a given type, 284 * overrides another method. 285 * When a non-abstract method overrides an abstract one, the 286 * former is also said to <i>implement</i> the latter. 287 * 288 * <p> In the simplest and most typical usage, the value of the 289 * {@code type} parameter will simply be the class or interface 290 * directly enclosing {@code overrider} (the possibly-overriding 291 * method). For example, suppose {@code m1} represents the method 292 * {@code String.hashCode} and {@code m2} represents {@code 293 * Object.hashCode}. We can then ask whether {@code m1} overrides 294 * {@code m2} within the class {@code String} (it does): 295 * 296 * <blockquote> 297 * {@code assert elements.overrides(m1, m2, 298 * elements.getTypeElement("java.lang.String")); } 299 * </blockquote> 300 * 301 * A more interesting case can be illustrated by the following example 302 * in which a method in type {@code A} does not override a 303 * like-named method in type {@code B}: 304 * 305 * <blockquote> 306 * {@code class A { public void m() {} } }<br> 307 * {@code interface B { void m(); } }<br> 308 * ...<br> 309 * {@code m1 = ...; // A.m }<br> 310 * {@code m2 = ...; // B.m }<br> 311 * {@code assert ! elements.overrides(m1, m2, 312 * elements.getTypeElement("A")); } 313 * </blockquote> 314 * 315 * When viewed as a member of a third type {@code C}, however, 316 * the method in {@code A} does override the one in {@code B}: 317 * 318 * <blockquote> 319 * {@code class C extends A implements B {} }<br> 320 * ...<br> 321 * {@code assert elements.overrides(m1, m2, 322 * elements.getTypeElement("C")); } 323 * </blockquote> 324 * 325 * @param overrider the first method, possible overrider 326 * @param overridden the second method, possibly being overridden 327 * @param type the type of which the first method is a member 328 * @return {@code true} if and only if the first method overrides 329 * the second 330 * @jls 8.4.8 Inheritance, Overriding, and Hiding 331 * @jls 9.4.1 Inheritance and Overriding 332 */ 333 boolean overrides(ExecutableElement overrider, ExecutableElement overridden, 334 TypeElement type); 335 336 /** 337 * Returns the text of a <i>constant expression</i> representing a 338 * primitive value or a string. 339 * The text returned is in a form suitable for representing the value 340 * in source code. 341 * 342 * @param value a primitive value or string 343 * @return the text of a constant expression 344 * @throws IllegalArgumentException if the argument is not a primitive 345 * value or string 346 * 347 * @see VariableElement#getConstantValue() 348 */ 349 String getConstantExpression(Object value); 350 351 /** 352 * Prints a representation of the elements to the given writer in 353 * the specified order. The main purpose of this method is for 354 * diagnostics. The exact format of the output is <em>not</em> 355 * specified and is subject to change. 356 * 357 * @param w the writer to print the output to 358 * @param elements the elements to print 359 */ 360 void printElements(java.io.Writer w, Element... elements); 361 362 /** 363 * Return a name with the same sequence of characters as the 364 * argument. 365 * 366 * @param cs the character sequence to return as a name 367 * @return a name with the same sequence of characters as the argument 368 */ 369 Name getName(CharSequence cs); 370 371 /** 372 * Returns {@code true} if the type element is a functional interface, {@code false} otherwise. 373 * 374 * @param type the type element being examined 375 * @return {@code true} if the element is a functional interface, {@code false} otherwise 376 * @jls 9.8 Functional Interfaces 377 * @since 1.8 378 */ 379 boolean isFunctionalInterface(TypeElement type); 380 }