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> and <em>present</em> are used 43 * throughout this interface to describe precisely which annotations 44 * are returned by methods: 45 * 46 * <p>An annotation <i>A</i> is <em>directly present</em> on a 47 * construct <i>E</i> if <i>E</i> is annotated, and: 48 * 49 * <ul> 50 * 51 * <li> for an invocation of {@code getAnnotation(Class<T>)} or 52 * {@code getAnnotationMirrors()}, <i>E</i>'s annotations contain <i>A</i>. 53 * 54 * <li> for an invocation of {@code getAnnotationsByType(Class<T>)}, 55 * <i>E</i>'s annotations either contain <i>A</i> or, if the type of 56 * <i>A</i> is repeatable, contain exactly one annotation whose value 57 * element contains <i>A</i> and whose type is the containing 58 * annotation type of <i>A</i>'s type. 59 * 60 * </ul> 61 * 62 * <p>An annotation A is <em>present</em> on a construct E if either: 63 * 64 * <ul> 65 * <li> <i>A</i> is <em>directly present</em> on <i>E</i>; or 66 * 67 * <li> <i>A</i> is not <em>directly present</em> on <i>E</i>, and 68 * <i>E</i> is an element representing a class, and <i>A</i>'s type 69 * is inheritable, and <i>A</i> is <em>present</em> on the element 70 * representing the superclass of <i>E</i>. 71 * 72 * </ul> 73 * 74 * @since 1.8 75 * @jls 9.6 Annotation Types 76 * @jls 9.6.3.3 @Inherited 77 */ 78 public interface AnnotatedConstruct { 79 /** 80 * Returns the annotations that are <em>directly present</em> on 81 * this construct. 82 * 83 * @return the annotations <em>directly present</em> on this 84 * construct; an empty list if there are none 85 */ 86 List<? extends AnnotationMirror> getAnnotationMirrors(); 87 88 /** 89 * Returns this construct's annotation of the 90 * specified type if such an annotation is <em>present</em>, else {@code 91 * null}. 92 * 93 * <p> The annotation returned by this method could contain an element 94 * whose value is of type {@code Class}. 95 * This value cannot be returned directly: information necessary to 96 * locate and load a class (such as the class loader to use) is 97 * not available, and the class might not be loadable at all. 98 * Attempting to read a {@code Class} object by invoking the relevant 99 * method on the returned annotation 100 * will result in a {@link MirroredTypeException}, 101 * from which the corresponding {@link TypeMirror} may be extracted. 102 * Similarly, attempting to read a {@code Class[]}-valued element 103 * will result in a {@link MirroredTypesException}. 104 * 105 * <blockquote> 106 * <i>Note:</i> This method is unlike others in this and related 107 * interfaces. It operates on runtime reflective information — 108 * representations of annotation types currently loaded into the 109 * VM — rather than on the representations defined by and used 110 * throughout these interfaces. Consequently, calling methods on 111 * the returned annotation object can throw many of the exceptions 112 * that can be thrown when calling methods on an annotation object 113 * returned by core reflection. This method is intended for 114 * callers that are written to operate on a known, fixed set of 115 * annotation types. 116 * </blockquote> 117 * 118 * @param <A> the annotation type 119 * @param annotationType the {@code Class} object corresponding to 120 * the annotation type 121 * @return this element's or type use's annotation for the 122 * specified annotation type if present on this element, else 123 * {@code null} 124 * 125 * @see #getAnnotationMirrors() 126 * @see java.lang.reflect.AnnotatedElement#getAnnotation 127 * @see EnumConstantNotPresentException 128 * @see AnnotationTypeMismatchException 129 * @see IncompleteAnnotationException 130 * @see MirroredTypeException 131 * @see MirroredTypesException 132 * @jls 9.6.1 Annotation Type Elements 133 */ 134 <A extends Annotation> A getAnnotation(Class<A> annotationType); 135 136 /** 137 * Returns annotations that are <em>present</em> on this construct. 138 * 139 * If there are no annotations <em>present</em> on this construct, 140 * the return value is an array of length 0. 141 * 142 * The difference between this method and {@link #getAnnotation(Class)} 143 * is that this method detects if its argument is a <em>repeatable 144 * annotation type</em>, and if so, attempts to find one or more 145 * annotations of that type by "looking through" a container annotation. 146 * 147 * <p> The annotations returned by this method could contain an element 148 * whose value is of type {@code Class}. 149 * This value cannot be returned directly: information necessary to 150 * locate and load a class (such as the class loader to use) is 151 * not available, and the class might not be loadable at all. 152 * Attempting to read a {@code Class} object by invoking the relevant 153 * method on the returned annotation 154 * will result in a {@link MirroredTypeException}, 155 * from which the corresponding {@link TypeMirror} may be extracted. 156 * Similarly, attempting to read a {@code Class[]}-valued element 157 * will result in a {@link MirroredTypesException}. 158 * 159 * <blockquote> 160 * <i>Note:</i> This method is unlike others in this and related 161 * interfaces. It operates on runtime reflective information — 162 * representations of annotation types currently loaded into the 163 * VM — rather than on the representations defined by and used 164 * throughout these interfaces. Consequently, calling methods on 165 * the returned annotation object can throw many of the exceptions 166 * that can be thrown when calling methods on an annotation object 167 * returned by core reflection. This method is intended for 168 * callers that are written to operate on a known, fixed set of 169 * annotation types. 170 * </blockquote> 171 * 172 * @param <A> the annotation type 173 * @param annotationType the {@code Class} object corresponding to 174 * the annotation type 175 * @return this element's annotations for the specified annotation 176 * type if present on this element, else an empty array 177 * 178 * @see #getAnnotationMirrors() 179 * @see #getAnnotation(java.lang.Class) 180 * @see java.lang.reflect.AnnotatedElement#getAnnotationsByType 181 * @see EnumConstantNotPresentException 182 * @see AnnotationTypeMismatchException 183 * @see IncompleteAnnotationException 184 * @see MirroredTypeException 185 * @see MirroredTypesException 186 * @jls 9.6 Annotation Types 187 * @jls 9.6.1 Annotation Type Elements 188 */ 189 <A extends Annotation> A[] getAnnotationsByType(Class<A> annotationType); 190 }