Java tutorial
/* * Copyright (c) 2005, 2018, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.annotation.processing; import javax.lang.model.element.Element; import javax.lang.model.element.TypeElement; import java.util.LinkedHashSet; import java.util.Collections; import java.util.Set; import java.lang.annotation.Annotation; /** * An annotation processing tool framework will {@linkplain * Processor#process provide an annotation processor with an object * implementing this interface} so that the processor can query for * information about a round of annotation processing. * * @author Joseph D. Darcy * @author Scott Seligman * @author Peter von der Ahé * @since 1.6 */ public interface RoundEnvironment { /** * Returns {@code true} if types generated by this round will not * be subject to a subsequent round of annotation processing; * returns {@code false} otherwise. * * @return {@code true} if types generated by this round will not * be subject to a subsequent round of annotation processing; * returns {@code false} otherwise */ boolean processingOver(); /** * Returns {@code true} if an error was raised in the prior round * of processing; returns {@code false} otherwise. * * @return {@code true} if an error was raised in the prior round * of processing; returns {@code false} otherwise */ boolean errorRaised(); /** * Returns the {@linkplain Processor root elements} for annotation processing generated * by the prior round. * * @return the root elements for annotation processing generated * by the prior round, or an empty set if there were none */ Set<? extends Element> getRootElements(); /** * Returns the elements annotated with the given annotation type. * The annotation may appear directly or be inherited. Only * package elements, module elements, and type elements <i>included</i> in this * round of annotation processing, or declarations of members, * constructors, parameters, or type parameters declared within * those, are returned. Included type elements are {@linkplain * #getRootElements root types} and any member types nested within * them. Elements of a package are not considered included simply * because a {@code package-info} file for that package was * created. * Likewise, elements of a module are not considered included * simply because a {@code module-info} file for that module was * created. * * @param a annotation type being requested * @return the elements annotated with the given annotation type, * or an empty set if there are none * @throws IllegalArgumentException if the argument does not * represent an annotation type */ Set<? extends Element> getElementsAnnotatedWith(TypeElement a); /** * Returns the elements annotated with one or more of the given * annotation types. * * @apiNote This method may be useful when processing repeating * annotations by looking for an annotation type and its * containing annotation type at the same time. * * @implSpec The default implementation of this method creates an * empty result set, iterates over the annotations in the argument * array calling {@link #getElementsAnnotatedWith(TypeElement)} on * each annotation and adding those results to the result * set. Finally, the contents of the result set are returned as an * unmodifiable set. * * @param annotations annotation types being requested * @return the elements annotated with one or more of the given * annotation types, or an empty set if there are none * @throws IllegalArgumentException if the any elements of the * argument set do not represent an annotation type * @jls 9.6.3 Repeatable Annotation Types * @since 9 */ default Set<? extends Element> getElementsAnnotatedWithAny(TypeElement... annotations) { // Use LinkedHashSet rather than HashSet for predictability Set<Element> result = new LinkedHashSet<>(); for (TypeElement annotation : annotations) { result.addAll(getElementsAnnotatedWith(annotation)); } return Collections.unmodifiableSet(result); } /** * Returns the elements annotated with the given annotation type. * The annotation may appear directly or be inherited. Only * package elements, module elements, and type elements <i>included</i> in this * round of annotation processing, or declarations of members, * constructors, parameters, or type parameters declared within * those, are returned. Included type elements are {@linkplain * #getRootElements root types} and any member types nested within * them. Elements in a package are not considered included simply * because a {@code package-info} file for that package was * created. * Likewise, elements of a module are not considered included * simply because a {@code module-info} file for that module was * created. * * <p> Note: An implementation of this method typically performs * an internal conversion from the runtime reflective * representation of an annotation type as a {@code Class} object * to a different representation used for annotation * processing. The set of annotation types present in the runtime * context may differ from the set of annotation types present in * the context of annotation processing in a particular * environmental configuration. If an runtime annotation type is * not present in the annotation processing context, the situation * is not treated as an error and no elements are found for that * annotation type. * * @param a annotation type being requested * @return the elements annotated with the given annotation type, * or an empty set if there are none * @throws IllegalArgumentException if the argument does not * represent an annotation type * * @see javax.lang.model.AnnotatedConstruct#getAnnotation(Class) * @see javax.lang.model.AnnotatedConstruct#getAnnotationsByType(Class) */ Set<? extends Element> getElementsAnnotatedWith(Class<? extends Annotation> a); /** * Returns the elements annotated with one or more of the given * annotation types. * * <p> Note: An implementation of this method typically performs * an internal conversion from the runtime reflective * representation of an annotation type as a {@code Class} object * to a different representation used for annotation * processing. The set of annotation types present in the runtime * context may differ from the set of annotation types present in * the context of annotation processing in a particular * environmental configuration. If an runtime annotation type is * not present in the annotation processing context, the situation * is not treated as an error and no elements are found for that * annotation type. * * @apiNote This method may be useful when processing repeating * annotations by looking for an annotation type and its * containing annotation type at the same time. * * @implSpec The default implementation of this method creates an * empty result set, iterates over the annotations in the argument * set calling {@link #getElementsAnnotatedWith(Class)} on * each annotation and adding those results to the result * set. Finally, the contents of the result set are returned as an * unmodifiable set. * * @param annotations annotation types being requested * @return the elements annotated with one or more of the given * annotation types, or an empty set if there are none * @throws IllegalArgumentException if the any elements of the * argument set do not represent an annotation type * @jls 9.6.3 Repeatable Annotation Types * * @see javax.lang.model.AnnotatedConstruct#getAnnotation(Class) * @see javax.lang.model.AnnotatedConstruct#getAnnotationsByType(Class) * * @since 9 */ default Set<? extends Element> getElementsAnnotatedWithAny(Set<Class<? extends Annotation>> annotations) { // Use LinkedHashSet rather than HashSet for predictability Set<Element> result = new LinkedHashSet<>(); for (Class<? extends Annotation> annotation : annotations) { result.addAll(getElementsAnnotatedWith(annotation)); } return Collections.unmodifiableSet(result); } }