Elements.java revision 3294:9adfb22ff08f
1/* 2 * Copyright (c) 2005, 2015, 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 26package javax.lang.model.util; 27 28 29import java.util.List; 30import java.util.Map; 31 32import javax.lang.model.element.*; 33 34 35/** 36 * Utility methods for operating on program elements. 37 * 38 * <p><b>Compatibility Note:</b> Methods may be added to this interface 39 * in future releases of the platform. 40 * 41 * @author Joseph D. Darcy 42 * @author Scott Seligman 43 * @author Peter von der Ahé 44 * @see javax.annotation.processing.ProcessingEnvironment#getElementUtils 45 * @since 1.6 46 */ 47public interface Elements { 48 49 /** 50 * Returns a package given its fully qualified name. 51 * 52 * @param name fully qualified package name, or "" for an unnamed package 53 * @return the named package, or {@code null} if it cannot be found 54 */ 55 PackageElement getPackageElement(CharSequence name); 56 57 /** 58 * Returns a type element given its canonical name. 59 * 60 * @param name the canonical name 61 * @return the named type element, or {@code null} if it cannot be found 62 */ 63 TypeElement getTypeElement(CharSequence name); 64 65 /** 66 * Returns a module element given its fully qualified name. 67 * 68 * @param name the name 69 * @return the named module element, or {@code null} if it cannot be found 70 * @since 9 71 */ 72 ModuleElement getModuleElement(CharSequence name); 73 74 /** 75 * Returns the values of an annotation's elements, including defaults. 76 * 77 * @see AnnotationMirror#getElementValues() 78 * @param a annotation to examine 79 * @return the values of the annotation's elements, including defaults 80 */ 81 Map<? extends ExecutableElement, ? extends AnnotationValue> 82 getElementValuesWithDefaults(AnnotationMirror a); 83 84 /** 85 * Returns the text of the documentation ("Javadoc") 86 * comment of an element. 87 * 88 * <p> A documentation comment of an element is a comment that 89 * begins with "{@code /**}" , ends with a separate 90 * "<code>*/</code>", and immediately precedes the element, 91 * ignoring white space. Therefore, a documentation comment 92 * contains at least three"{@code *}" characters. The text 93 * returned for the documentation comment is a processed form of 94 * the comment as it appears in source code. The leading "{@code 95 * /**}" and trailing "<code>*/</code>" are removed. For lines 96 * of the comment starting after the initial "{@code /**}", 97 * leading white space characters are discarded as are any 98 * consecutive "{@code *}" characters appearing after the white 99 * space or starting the line. The processed lines are then 100 * concatenated together (including line terminators) and 101 * returned. 102 * 103 * @param e the element being examined 104 * @return the documentation comment of the element, or {@code null} 105 * if there is none 106 * @jls 3.6 White Space 107 */ 108 String getDocComment(Element e); 109 110 /** 111 * Returns {@code true} if the element is deprecated, {@code false} otherwise. 112 * 113 * @param e the element being examined 114 * @return {@code true} if the element is deprecated, {@code false} otherwise 115 */ 116 boolean isDeprecated(Element e); 117 118 /** 119 * Returns the <i>binary name</i> of a type element. 120 * 121 * @param type the type element being examined 122 * @return the binary name 123 * 124 * @see TypeElement#getQualifiedName 125 * @jls 13.1 The Form of a Binary 126 */ 127 Name getBinaryName(TypeElement type); 128 129 130 /** 131 * Returns the package of an element. The package of a package is 132 * itself. 133 * 134 * @param type the element being examined 135 * @return the package of an element 136 */ 137 PackageElement getPackageOf(Element type); 138 139 /** 140 * Returns the module of an element. The module of a module is 141 * itself. 142 * 143 * @param type the element being examined 144 * @return the module of an element 145 * @since 9 146 */ 147 ModuleElement getModuleOf(Element type); 148 149 /** 150 * Returns all members of a type element, whether inherited or 151 * declared directly. For a class the result also includes its 152 * constructors, but not local or anonymous classes. 153 * 154 * <p>Note that elements of certain kinds can be isolated using 155 * methods in {@link ElementFilter}. 156 * 157 * @param type the type being examined 158 * @return all members of the type 159 * @see Element#getEnclosedElements 160 */ 161 List<? extends Element> getAllMembers(TypeElement type); 162 163 /** 164 * Returns all annotations <i>present</i> on an element, whether 165 * directly present or present via inheritance. 166 * 167 * @param e the element being examined 168 * @return all annotations of the element 169 * @see Element#getAnnotationMirrors 170 * @see javax.lang.model.AnnotatedConstruct 171 */ 172 List<? extends AnnotationMirror> getAllAnnotationMirrors(Element e); 173 174 /** 175 * Tests whether one type, method, or field hides another. 176 * 177 * @param hider the first element 178 * @param hidden the second element 179 * @return {@code true} if and only if the first element hides 180 * the second 181 */ 182 boolean hides(Element hider, Element hidden); 183 184 /** 185 * Tests whether one method, as a member of a given type, 186 * overrides another method. 187 * When a non-abstract method overrides an abstract one, the 188 * former is also said to <i>implement</i> the latter. 189 * 190 * <p> In the simplest and most typical usage, the value of the 191 * {@code type} parameter will simply be the class or interface 192 * directly enclosing {@code overrider} (the possibly-overriding 193 * method). For example, suppose {@code m1} represents the method 194 * {@code String.hashCode} and {@code m2} represents {@code 195 * Object.hashCode}. We can then ask whether {@code m1} overrides 196 * {@code m2} within the class {@code String} (it does): 197 * 198 * <blockquote> 199 * {@code assert elements.overrides(m1, m2, 200 * elements.getTypeElement("java.lang.String")); } 201 * </blockquote> 202 * 203 * A more interesting case can be illustrated by the following example 204 * in which a method in type {@code A} does not override a 205 * like-named method in type {@code B}: 206 * 207 * <blockquote> 208 * {@code class A { public void m() {} } }<br> 209 * {@code interface B { void m(); } }<br> 210 * ...<br> 211 * {@code m1 = ...; // A.m }<br> 212 * {@code m2 = ...; // B.m }<br> 213 * {@code assert ! elements.overrides(m1, m2, 214 * elements.getTypeElement("A")); } 215 * </blockquote> 216 * 217 * When viewed as a member of a third type {@code C}, however, 218 * the method in {@code A} does override the one in {@code B}: 219 * 220 * <blockquote> 221 * {@code class C extends A implements B {} }<br> 222 * ...<br> 223 * {@code assert elements.overrides(m1, m2, 224 * elements.getTypeElement("C")); } 225 * </blockquote> 226 * 227 * @param overrider the first method, possible overrider 228 * @param overridden the second method, possibly being overridden 229 * @param type the type of which the first method is a member 230 * @return {@code true} if and only if the first method overrides 231 * the second 232 * @jls 8.4.8 Inheritance, Overriding, and Hiding 233 * @jls 9.4.1 Inheritance and Overriding 234 */ 235 boolean overrides(ExecutableElement overrider, ExecutableElement overridden, 236 TypeElement type); 237 238 /** 239 * Returns the text of a <i>constant expression</i> representing a 240 * primitive value or a string. 241 * The text returned is in a form suitable for representing the value 242 * in source code. 243 * 244 * @param value a primitive value or string 245 * @return the text of a constant expression 246 * @throws IllegalArgumentException if the argument is not a primitive 247 * value or string 248 * 249 * @see VariableElement#getConstantValue() 250 */ 251 String getConstantExpression(Object value); 252 253 /** 254 * Prints a representation of the elements to the given writer in 255 * the specified order. The main purpose of this method is for 256 * diagnostics. The exact format of the output is <em>not</em> 257 * specified and is subject to change. 258 * 259 * @param w the writer to print the output to 260 * @param elements the elements to print 261 */ 262 void printElements(java.io.Writer w, Element... elements); 263 264 /** 265 * Return a name with the same sequence of characters as the 266 * argument. 267 * 268 * @param cs the character sequence to return as a name 269 * @return a name with the same sequence of characters as the argument 270 */ 271 Name getName(CharSequence cs); 272 273 /** 274 * Returns {@code true} if the type element is a functional interface, {@code false} otherwise. 275 * 276 * @param type the type element being examined 277 * @return {@code true} if the element is a functional interface, {@code false} otherwise 278 * @jls 9.8 Functional Interfaces 279 * @since 1.8 280 */ 281 boolean isFunctionalInterface(TypeElement type); 282} 283