90 lines
3.4 KiB
Java
90 lines
3.4 KiB
Java
/*
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* Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.lang.annotation;
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/**
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* Indicates the contexts in which an annotation interface is applicable. The
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* declaration contexts and type contexts in which an annotation interface may
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* be applicable are specified in JLS {@jls 9.6.4.1}, and denoted in source code by
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* enum constants of {@link ElementType java.lang.annotation.ElementType}.
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*
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* <p>If an {@code @Target} meta-annotation is not present on an annotation
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* interface {@code T}, then an annotation of type {@code T} may be written as
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* a modifier for any declaration.
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*
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* <p>If an {@code @Target} meta-annotation is present, the compiler will enforce
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* the usage restrictions indicated by {@code ElementType}
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* enum constants, in line with JLS {@jls 9.7.4}.
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*
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* <p>For example, this {@code @Target} meta-annotation indicates that the
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* declared interface is itself a meta-annotation interface. It can only be
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* used on annotation interface declarations:
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* <pre>
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* @Target(ElementType.ANNOTATION_TYPE)
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* public @interface MetaAnnotationType {
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* ...
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* }
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* </pre>
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*
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* <p>This {@code @Target} meta-annotation indicates that the declared class or
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* interface is intended solely for use as a member class or interface in
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* complex annotation interface declarations. It cannot be used to annotate
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* anything directly:
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* <pre>
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* @Target({})
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* public @interface MemberInterface {
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* ...
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* }
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* </pre>
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*
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* <p>It is a compile-time error for a single {@code ElementType} constant to
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* appear more than once in an {@code @Target} annotation. For example, the
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* following {@code @Target} meta-annotation is illegal:
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* <pre>
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* @Target({ElementType.FIELD, ElementType.METHOD, ElementType.FIELD})
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* public @interface Bogus {
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* ...
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* }
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* </pre>
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*
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* @since 1.5
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* @jls 9.6.4.1 @Target
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* @jls 9.7.4 Where Annotations May Appear
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* @jls 9.7.5 Multiple Annotations of the Same Interface
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*/
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@Documented
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@Retention(RetentionPolicy.RUNTIME)
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@Target(ElementType.ANNOTATION_TYPE)
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public @interface Target {
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/**
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* Returns an array of the kinds of elements an annotation interface
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* can be applied to.
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* @return an array of the kinds of elements an annotation interface
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* can be applied to
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*/
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ElementType[] value();
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}
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