1 /* 2 * Copyright (c) 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; 27 28 import java.lang.annotation.*; 29 import java.util.List; 30 import javax.lang.model.element.*; 31 import javax.lang.model.type.*; 32 33 /** 34 * Represents a construct that can be annotated. 35 * 36 * A construct is either an {@linkplain 37 * javax.lang.model.element.Element element} or a {@linkplain 38 * javax.lang.model.type.TypeMirror type}. Annotations on an element 39 * are on a <em>declaration</em>, whereas annotations on a type are on 40 * a specific <em>use</em> of a type name. 41 * 42 * The terms <em>directly present</em>, <em>present</em>, 43 * <em>indirectly present</em>, and <em>associated </em> are used 44 * throughout this interface to describe precisely which annotations 45 * are returned by the methods defined herein. 46 * 47 * <p>In the definitions below, an annotation <i>A</i> has an 48 * annotation type <i>AT</i>. If <i>AT</i> is a repeatable annotation 49 * type, the type of the containing annotation is <i>ATC</i>. 50 * 51 * <p>Annotation <i>A</i> is <em>directly present</em> on a construct 52 * <i>C</i> if either: 53 * 54 * <ul> 55 * 56 * <li><i>A</i> is explicitly or implicitly declared as applying to 57 * the source code representation of <i>C</i>. 58 * 59 * <p>Typically, if exactly one annotation of type <i>AT</i> appears in 60 * the source code of representation of <i>C</i>, then <i>A</i> is 61 * explicitly declared as applying to <i>C</i>. 62 * 63 * If there are multiple annotations of type <i>AT</i> present on 64 * <i>C</i>, then if <i>AT</i> is repeatable annotation type, an 65 * annotation of type <i>ATC</i> is implicitly declared on <i>C</i>. 66 * 67 * <li> A representation of <i>A</i> appears in the executable output 68 * for <i>C</i>, such as the {@code RuntimeVisibleAnnotations} or 69 * {@code RuntimeVisibleParameterAnnotations} attributes of a class 70 * file. 71 * 72 * </ul> 73 * 74 * <p>An annotation <i>A</i> is <em>present</em> on a 75 * construct <i>C</i> if either: 76 * <ul> 77 * 78 * <li><i>A</i> is directly present on <i>C</i>. 79 * 80 * <li>No annotation of type <i>AT</i> is directly present on 81 * <i>C</i>, and <i>C</i> is a class and <i>AT</i> is inheritable 82 * and <i>A</i> is present on the superclass of <i>C</i>. 83 * 84 * </ul> 85 * 86 * An annotation <i>A</i> is <em>indirectly present</em> on a construct 87 * <i>C</i> if both: 88 * 89 * <ul> 90 * 91 * <li><i>AT</i> is a repeatable annotation type with a containing 92 * annotation type <i>ATC</i>. 93 * 94 * <li>An annotation of type <i>ATC</i> is directly present on 95 * <i>C</i> and <i>A</i> is an annotation included in the result of 96 * calling the {@code value} method of the directly present annotation 97 * of type <i>ATC</i>. 98 * 99 * </ul> 100 * 101 * An annotation <i>A</i> is <em>associated</em> with a construct 102 * <i>C</i> if either: 103 * 104 * <ul> 105 * 106 * <li> <i>A</i> is directly or indirectly present on <i>C</i>. 107 * 108 * <li> No annotation of type <i>AT</i> is directly or indirectly 109 * present on <i>C</i>, and <i>C</i> is a class, and <i>AT</i> is 110 * inheritable, and <i>A</i> is associated with the superclass of 111 * <i>C</i>. 112 * 113 * </ul> 114 * 115 * @since 1.8 116 * @jls 9.6 Annotation Types 117 * @jls 9.6.3.3 @Inherited 118 */ 119 public interface AnnotatedConstruct { 120 /** 121 * Returns the annotations that are <em>directly present</em> on 122 * this construct. 123 * 124 * @return the annotations <em>directly present</em> on this 125 * construct; an empty list if there are none 126 */ getAnnotationMirrors()127 List<? extends AnnotationMirror> getAnnotationMirrors(); 128 129 /** 130 * Returns this construct's annotation of the specified type if 131 * such an annotation is <em>present</em>, else {@code null}. 132 * 133 * <p> The annotation returned by this method could contain an element 134 * whose value is of type {@code Class}. 135 * This value cannot be returned directly: information necessary to 136 * locate and load a class (such as the class loader to use) is 137 * not available, and the class might not be loadable at all. 138 * Attempting to read a {@code Class} object by invoking the relevant 139 * method on the returned annotation 140 * will result in a {@link MirroredTypeException}, 141 * from which the corresponding {@link TypeMirror} may be extracted. 142 * Similarly, attempting to read a {@code Class[]}-valued element 143 * will result in a {@link MirroredTypesException}. 144 * 145 * <blockquote> 146 * <i>Note:</i> This method is unlike others in this and related 147 * interfaces. It operates on runtime reflective information — 148 * representations of annotation types currently loaded into the 149 * VM — rather than on the representations defined by and used 150 * throughout these interfaces. Consequently, calling methods on 151 * the returned annotation object can throw many of the exceptions 152 * that can be thrown when calling methods on an annotation object 153 * returned by core reflection. This method is intended for 154 * callers that are written to operate on a known, fixed set of 155 * annotation types. 156 * </blockquote> 157 * 158 * @param <A> the annotation type 159 * @param annotationType the {@code Class} object corresponding to 160 * the annotation type 161 * @return this construct's annotation for the specified 162 * annotation type if present, else {@code null} 163 * 164 * @see #getAnnotationMirrors() 165 * @see java.lang.reflect.AnnotatedElement#getAnnotation 166 * @see EnumConstantNotPresentException 167 * @see AnnotationTypeMismatchException 168 * @see IncompleteAnnotationException 169 * @see MirroredTypeException 170 * @see MirroredTypesException 171 * @jls 9.6.1 Annotation Type Elements 172 */ getAnnotation(Class<A> annotationType)173 <A extends Annotation> A getAnnotation(Class<A> annotationType); 174 175 /** 176 * Returns annotations that are <em>associated</em> with this construct. 177 * 178 * If there are no annotations associated with this construct, the 179 * return value is an array of length 0. 180 * 181 * The order of annotations which are directly or indirectly 182 * present on a construct <i>C</i> is computed as if indirectly present 183 * annotations on <i>C</i> are directly present on <i>C</i> in place of their 184 * container annotation, in the order in which they appear in the 185 * value element of the container annotation. 186 * 187 * The difference between this method and {@link #getAnnotation(Class)} 188 * is that this method detects if its argument is a <em>repeatable 189 * annotation type</em>, and if so, attempts to find one or more 190 * annotations of that type by "looking through" a container annotation. 191 * 192 * <p> The annotations returned by this method could contain an element 193 * whose value is of type {@code Class}. 194 * This value cannot be returned directly: information necessary to 195 * locate and load a class (such as the class loader to use) is 196 * not available, and the class might not be loadable at all. 197 * Attempting to read a {@code Class} object by invoking the relevant 198 * method on the returned annotation 199 * will result in a {@link MirroredTypeException}, 200 * from which the corresponding {@link TypeMirror} may be extracted. 201 * Similarly, attempting to read a {@code Class[]}-valued element 202 * will result in a {@link MirroredTypesException}. 203 * 204 * <blockquote> 205 * <i>Note:</i> This method is unlike others in this and related 206 * interfaces. It operates on runtime reflective information — 207 * representations of annotation types currently loaded into the 208 * VM — rather than on the representations defined by and used 209 * throughout these interfaces. Consequently, calling methods on 210 * the returned annotation object can throw many of the exceptions 211 * that can be thrown when calling methods on an annotation object 212 * returned by core reflection. This method is intended for 213 * callers that are written to operate on a known, fixed set of 214 * annotation types. 215 * </blockquote> 216 * 217 * @param <A> the annotation type 218 * @param annotationType the {@code Class} object corresponding to 219 * the annotation type 220 * @return this construct's annotations for the specified annotation 221 * type if present on this construct, else an empty array 222 * 223 * @see #getAnnotationMirrors() 224 * @see #getAnnotation(Class) 225 * @see java.lang.reflect.AnnotatedElement#getAnnotationsByType(Class) 226 * @see EnumConstantNotPresentException 227 * @see AnnotationTypeMismatchException 228 * @see IncompleteAnnotationException 229 * @see MirroredTypeException 230 * @see MirroredTypesException 231 * @jls 9.6 Annotation Types 232 * @jls 9.6.1 Annotation Type Elements 233 */ getAnnotationsByType(Class<A> annotationType)234 <A extends Annotation> A[] getAnnotationsByType(Class<A> annotationType); 235 } 236