1 /* 2 * Copyright (c) 2005, 2013, 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.element.*; 33 import javax.lang.model.type.*; 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 "" 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 type element given its canonical name. 60 * 61 * @param name the canonical name 62 * @return the named type element, or {@code null} if it cannot be found 63 */ 64 TypeElement getTypeElement(CharSequence name); 65 66 /** 67 * Returns the values of an annotation's elements, including defaults. 68 * 69 * @see AnnotationMirror#getElementValues() 70 * @param a annotation to examine 71 * @return the values of the annotation's elements, including defaults 72 */ 73 Map<? extends ExecutableElement, ? extends AnnotationValue> 74 getElementValuesWithDefaults(AnnotationMirror a); 75 76 /** 77 * Returns the text of the documentation ("Javadoc") 78 * comment of an element. 79 * 80 * <p> A documentation comment of an element is a comment that 81 * begins with "{@code /**}" , ends with a separate 82 * "<code>*/</code>", and immediately precedes the element, 83 * ignoring white space. Therefore, a documentation comment 84 * contains at least three"{@code *}" characters. The text 85 * returned for the documentation comment is a processed form of 86 * the comment as it appears in source code. The leading "{@code 87 * /**}" and trailing "<code>*/</code>" are removed. For lines 88 * of the comment starting after the initial "{@code /**}", 89 * leading white space characters are discarded as are any 90 * consecutive "{@code *}" characters appearing after the white 91 * space or starting the line. The processed lines are then 92 * concatenated together (including line terminators) and 93 * returned. 94 * 95 * @param e the element being examined 96 * @return the documentation comment of the element, or {@code null} 97 * if there is none 98 * @jls 3.6 White Space 99 */ 100 String getDocComment(Element e); 101 102 /** 103 * Returns {@code true} if the element is deprecated, {@code false} otherwise. 104 * 105 * @param e the element being examined 106 * @return {@code true} if the element is deprecated, {@code false} otherwise 107 */ 108 boolean isDeprecated(Element e); 109 110 /** 111 * Returns the <i>binary name</i> of a type element. 112 * 113 * @param type the type element being examined 114 * @return the binary name 115 * 116 * @see TypeElement#getQualifiedName 117 * @jls 13.1 The Form of a Binary 118 */ 119 Name getBinaryName(TypeElement type); 120 121 122 /** 123 * Returns the package of an element. The package of a package is 124 * itself. 125 * 126 * @param type the element being examined 127 * @return the package of an element 128 */ 129 PackageElement getPackageOf(Element type); 130 131 /** 132 * Returns all members of a type element, whether inherited or 133 * declared directly. For a class the result also includes its 134 * constructors, but not local or anonymous classes. 135 * 136 * <p>Note that elements of certain kinds can be isolated using 137 * methods in {@link ElementFilter}. 138 * 139 * @param type the type being examined 140 * @return all members of the type 141 * @see Element#getEnclosedElements 142 */ 143 List<? extends Element> getAllMembers(TypeElement type); 144 145 /** 146 * Returns all annotations <i>present</i> on an element, whether 147 * directly present or present via inheritance. 148 * 149 * @param e the element being examined 150 * @return all annotations of the element 151 * @see Element#getAnnotationMirrors 152 * @see javax.lang.model.AnnotatedConstruct 153 */ 154 List<? extends AnnotationMirror> getAllAnnotationMirrors(Element e); 155 156 /** 157 * Tests whether one type, method, or field hides another. 158 * 159 * @param hider the first element 160 * @param hidden the second element 161 * @return {@code true} if and only if the first element hides 162 * the second 163 */ 164 boolean hides(Element hider, Element hidden); 165 166 /** 167 * Tests whether one method, as a member of a given type, 168 * overrides another method. 169 * When a non-abstract method overrides an abstract one, the 170 * former is also said to <i>implement</i> the latter. 171 * 172 * <p> In the simplest and most typical usage, the value of the 173 * {@code type} parameter will simply be the class or interface 174 * directly enclosing {@code overrider} (the possibly-overriding 175 * method). For example, suppose {@code m1} represents the method 176 * {@code String.hashCode} and {@code m2} represents {@code 177 * Object.hashCode}. We can then ask whether {@code m1} overrides 178 * {@code m2} within the class {@code String} (it does): 179 * 180 * <blockquote> 181 * {@code assert elements.overrides(m1, m2, 182 * elements.getTypeElement("java.lang.String")); } 183 * </blockquote> 184 * 185 * A more interesting case can be illustrated by the following example 186 * in which a method in type {@code A} does not override a 187 * like-named method in type {@code B}: 188 * 189 * <blockquote> 190 * {@code class A { public void m() {} } }<br> 191 * {@code interface B { void m(); } }<br> 192 * ...<br> 193 * {@code m1 = ...; // A.m }<br> 194 * {@code m2 = ...; // B.m }<br> 195 * {@code assert ! elements.overrides(m1, m2, 196 * elements.getTypeElement("A")); } 197 * </blockquote> 198 * 199 * When viewed as a member of a third type {@code C}, however, 200 * the method in {@code A} does override the one in {@code B}: 201 * 202 * <blockquote> 203 * {@code class C extends A implements B {} }<br> 204 * ...<br> 205 * {@code assert elements.overrides(m1, m2, 206 * elements.getTypeElement("C")); } 207 * </blockquote> 208 * 209 * @param overrider the first method, possible overrider 210 * @param overridden the second method, possibly being overridden 211 * @param type the type of which the first method is a member 212 * @return {@code true} if and only if the first method overrides 213 * the second 214 * @jls 8.4.8 Inheritance, Overriding, and Hiding 215 * @jls 9.4.1 Inheritance and Overriding 216 */ 217 boolean overrides(ExecutableElement overrider, ExecutableElement overridden, 218 TypeElement type); 219 220 /** 221 * Returns the text of a <i>constant expression</i> representing a 222 * primitive value or a string. 223 * The text returned is in a form suitable for representing the value 224 * in source code. 225 * 226 * @param value a primitive value or string 227 * @return the text of a constant expression 228 * @throws IllegalArgumentException if the argument is not a primitive 229 * value or string 230 * 231 * @see VariableElement#getConstantValue() 232 */ 233 String getConstantExpression(Object value); 234 235 /** 236 * Prints a representation of the elements to the given writer in 237 * the specified order. The main purpose of this method is for 238 * diagnostics. The exact format of the output is <em>not</em> 239 * specified and is subject to change. 240 * 241 * @param w the writer to print the output to 242 * @param elements the elements to print 243 */ 244 void printElements(java.io.Writer w, Element... elements); 245 246 /** 247 * Return a name with the same sequence of characters as the 248 * argument. 249 * 250 * @param cs the character sequence to return as a name 251 * @return a name with the same sequence of characters as the argument 252 */ 253 Name getName(CharSequence cs); 254 255 /** 256 * Returns {@code true} if the type element is a functional interface, {@code false} otherwise. 257 * 258 * @param type the type element being examined 259 * @return {@code true} if the element is a functional interface, {@code false} otherwise 260 * @jls 9.8 Functional Interfaces 261 * @since 1.8 262 */ 263 boolean isFunctionalInterface(TypeElement type); 264 }