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	/*
	* Copyright (c) 2003, 2020, 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
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	*/

	package java.lang.reflect;

	import java.lang.annotation.Annotation;
	import java.lang.annotation.AnnotationFormatError;
	import java.lang.annotation.Repeatable;
	import java.util.Arrays;
	import java.util.LinkedHashMap;
	import java.util.Map;
	import java.util.Objects;
	import java.util.function.Function;
	import java.util.stream.Collectors;
	import sun.reflect.annotation.AnnotationSupport;
	import sun.reflect.annotation.AnnotationType;

	/**
	* Represents an annotated construct of the program currently running
	* in this VM.
	*
	* A construct is either an element or a type. Annotations on an
	* element are on a <em>declaration</em>, whereas annotations on a
	* type are on a specific <em>use</em> of a type name.
	*
	* As defined by <cite>The Java Language Specification</cite>
	* section {@jls 9.7.4}, an annotation on an element is a
	* <em>declaration annotation</em> and an annotation on a type is a
	* <em>type annotation</em>.
	*
	* Note that any annotations returned by methods on the {@link
	* AnnotatedType AnnotatedType} interface and its subinterfaces are
	* type annotations as the entity being potentially annotated is a
	* type. Annotations returned by methods outside of the {@code
	* AnnotatedType} hierarchy are declaration annotations.
	*
	* <p>This interface allows annotations to be read reflectively. All
	* annotations returned by methods in this interface are immutable and
	* serializable. The arrays returned by methods of this interface may
	* be modified by callers without affecting the arrays returned to
	* other callers.
	*
	* <p>The {@link #getAnnotationsByType(Class)} and {@link
	* #getDeclaredAnnotationsByType(Class)} methods support multiple
	* annotations of the same type on an element. If the argument to
	* either method is a repeatable annotation type (JLS {@jls 9.6}),
	* then the method will "look through" a container annotation (JLS
	* {@jls 9.7}), if present, and return any annotations inside the
	* container. Container annotations may be generated at compile-time
	* to wrap multiple annotations of the argument type.
	*
	* <p>The terms <em>directly present</em>, <em>indirectly present</em>,
	* <em>present</em>, and <em>associated</em> are used throughout this
	* interface to describe precisely which annotations are returned by
	* methods:
	*
	* <ul>
	*
	* <li> An annotation <i>A</i> is <em>directly present</em> on an
	* element <i>E</i> if <i>E</i> has a {@code
	* RuntimeVisibleAnnotations} or {@code
	* RuntimeVisibleParameterAnnotations} or {@code
	* RuntimeVisibleTypeAnnotations} attribute, and the attribute
	* contains <i>A</i>.
	*
	* <li>An annotation <i>A</i> is <em>indirectly present</em> on an
	* element <i>E</i> if <i>E</i> has a {@code RuntimeVisibleAnnotations} or
	* {@code RuntimeVisibleParameterAnnotations} or {@code RuntimeVisibleTypeAnnotations}
	* attribute, and <i>A</i> 's type is repeatable, and the attribute contains
	* exactly one annotation whose value element contains <i>A</i> and whose
	* type is the containing annotation type of <i>A</i> 's type.
	*
	* <li>An annotation <i>A</i> is <em>present</em> on an element <i>E</i> if either:
	*
	* <ul>
	*
	* <li><i>A</i> is directly present on <i>E</i>; or
	*
	* <li>No annotation of <i>A</i> 's type is directly present on
	* <i>E</i>, and <i>E</i> is a class, and <i>A</i> 's type is
	* inheritable, and <i>A</i> is present on the superclass of <i>E</i>.
	*
	* </ul>
	*
	* <li>An annotation <i>A</i> is <em>associated</em> with an element <i>E</i>
	* if either:
	*
	* <ul>
	*
	* <li><i>A</i> is directly or indirectly present on <i>E</i>; or
	*
	* <li>No annotation of <i>A</i> 's type is directly or indirectly
	* present on <i>E</i>, and <i>E</i> is a class, and <i>A</i>'s type
	* is inheritable, and <i>A</i> is associated with the superclass of
	* <i>E</i>.
	*
	* </ul>
	*
	* </ul>
	*
	* <p>The table below summarizes which kind of annotation presence
	* different methods in this interface examine.
	*
	* <table class="plain">
	* <caption>Overview of kind of presence detected by different AnnotatedElement methods</caption>
	* <thead>
	* <tr><th colspan=2 scope="col">Method</th>
	* <th colspan=4 scope="col">Kind of Presence</th>
	* <tr><th scope="col">Return Type</th>
	* <th scope="col">Signature</th>
	* <th scope="col">Directly Present</th>
	* <th scope="col">Indirectly Present</th>
	* <th scope="col">Present</th>
	* <th scope="col">Associated</th>
	* </thead>
	* <tbody>
	* <tr><td style="text-align:right">{@code T}</td>
	* <th scope="row" style="font-weight:normal; text-align:left">{@link #getAnnotation(Class) getAnnotation(Class<T>)}
	* <td></td><td></td><td style="text-align:center">X</td><td></td>
	* </tr>
	* <tr><td style="text-align:right">{@code Annotation[]}</td>
	* <th scope="row" style="font-weight:normal; text-align:left">{@link #getAnnotations getAnnotations()}
	* <td></td><td></td><td style="text-align:center">X</td><td></td>
	* </tr>
	* <tr><td style="text-align:right">{@code T[]}</td>
	* <th scope="row" style="font-weight:normal; text-align:left">{@link #getAnnotationsByType(Class) getAnnotationsByType(Class<T>)}
	* <td></td><td></td><td></td><td style="text-align:center">X</td>
	* </tr>
	* <tr><td style="text-align:right">{@code T}</td>
	* <th scope="row" style="font-weight:normal; text-align:left">{@link #getDeclaredAnnotation(Class) getDeclaredAnnotation(Class<T>)}
	* <td style="text-align:center">X</td><td></td><td></td><td></td>
	* </tr>
	* <tr><td style="text-align:right">{@code Annotation[]}</td>
	* <th scope="row" style="font-weight:normal; text-align:left">{@link #getDeclaredAnnotations getDeclaredAnnotations()}
	* <td style="text-align:center">X</td><td></td><td></td><td></td>
	* </tr>
	* <tr><td style="text-align:right">{@code T[]}</td>
	* <th scope="row" style="font-weight:normal; text-align:left">{@link #getDeclaredAnnotationsByType(Class) getDeclaredAnnotationsByType(Class<T>)}
	* <td style="text-align:center">X</td><td style="text-align:center">X</td><td></td><td></td>
	* </tr>
	* </tbody>
	* </table>
	*
	* <p>For an invocation of {@code get[Declared]AnnotationsByType(Class <T>)},
	* the order of annotations which are directly or indirectly
	* present on an element <i>E</i> is computed as if indirectly present
	* annotations on <i>E</i> are directly present on <i>E</i> in place
	* of their container annotation, in the order in which they appear in
	* the value element of the container annotation.
	*
	* <p>There are several compatibility concerns to keep in mind if an
	* annotation type <i>T</i> is originally <em>not</em> repeatable and
	* later modified to be repeatable.
	*
	* The containing annotation type for <i>T</i> is <i>TC</i>.
	*
	* <ul>
	*
	* <li>Modifying <i>T</i> to be repeatable is source and binary
	* compatible with existing uses of <i>T</i> and with existing uses
	* of <i>TC</i>.
	*
	* That is, for source compatibility, source code with annotations of
	* type <i>T</i> or of type <i>TC</i> will still compile. For binary
	* compatibility, class files with annotations of type <i>T</i> or of
	* type <i>TC</i> (or with other kinds of uses of type <i>T</i> or of
	* type <i>TC</i>) will link against the modified version of <i>T</i>
	* if they linked against the earlier version.
	*
	* (An annotation type <i>TC</i> may informally serve as an acting
	* containing annotation type before <i>T</i> is modified to be
	* formally repeatable. Alternatively, when <i>T</i> is made
	* repeatable, <i>TC</i> can be introduced as a new type.)
	*
	* <li>If an annotation type <i>TC</i> is present on an element, and
	* <i>T</i> is modified to be repeatable with <i>TC</i> as its
	* containing annotation type then:
	*
	* <ul>
	*
	* <li>The change to <i>T</i> is behaviorally compatible with respect
	* to the {@code get[Declared]Annotation(Class<T>)} (called with an
	* argument of <i>T</i> or <i>TC</i>) and {@code
	* get[Declared]Annotations()} methods because the results of the
	* methods will not change due to <i>TC</i> becoming the containing
	* annotation type for <i>T</i>.
	*
	* <li>The change to <i>T</i> changes the results of the {@code
	* get[Declared]AnnotationsByType(Class<T>)} methods called with an
	* argument of <i>T</i>, because those methods will now recognize an
	* annotation of type <i>TC</i> as a container annotation for <i>T</i>
	* and will "look through" it to expose annotations of type <i>T</i>.
	*
	* </ul>
	*
	* <li>If an annotation of type <i>T</i> is present on an
	* element and <i>T</i> is made repeatable and more annotations of
	* type <i>T</i> are added to the element:
	*
	* <ul>
	*
	* <li> The addition of the annotations of type <i>T</i> is both
	* source compatible and binary compatible.
	*
	* <li>The addition of the annotations of type <i>T</i> changes the results
	* of the {@code get[Declared]Annotation(Class<T>)} methods and {@code
	* get[Declared]Annotations()} methods, because those methods will now
	* only see a container annotation on the element and not see an
	* annotation of type <i>T</i>.
	*
	* <li>The addition of the annotations of type <i>T</i> changes the
	* results of the {@code get[Declared]AnnotationsByType(Class<T>)}
	* methods, because their results will expose the additional
	* annotations of type <i>T</i> whereas previously they exposed only a
	* single annotation of type <i>T</i>.
	*
	* </ul>
	*
	* </ul>
	*
	* <p>If an annotation returned by a method in this interface contains
	* (directly or indirectly) a {@link Class}-valued member referring to
	* a class that is not accessible in this VM, attempting to read the class
	* by calling the relevant Class-returning method on the returned annotation
	* will result in a {@link TypeNotPresentException}.
	*
	* <p>Similarly, attempting to read an enum-valued member will result in
	* a {@link EnumConstantNotPresentException} if the enum constant in the
	* annotation is no longer present in the enum class.
	*
	* <p>If an annotation type <i>T</i> is (meta-)annotated with an
	* {@code @Repeatable} annotation whose value element indicates a type
	* <i>TC</i>, but <i>TC</i> does not declare a {@code value()} method
	* with a return type of <i>T</i>{@code []}, then an exception of type
	* {@link java.lang.annotation.AnnotationFormatError} is thrown.
	*
	* <p>Finally, attempting to read a member whose definition has evolved
	* incompatibly will result in a {@link
	* java.lang.annotation.AnnotationTypeMismatchException} or an
	* {@link java.lang.annotation.IncompleteAnnotationException}.
	*
	* @see java.lang.EnumConstantNotPresentException
	* @see java.lang.TypeNotPresentException
	* @see AnnotationFormatError
	* @see java.lang.annotation.AnnotationTypeMismatchException
	* @see java.lang.annotation.IncompleteAnnotationException
	* @since 1.5
	* @author Josh Bloch
	*/
	public interface AnnotatedElement {
	/**
	* Returns true if an annotation for the specified type
	* is <em>present</em> on this element, else false. This method
	* is designed primarily for convenient access to marker annotations.
	*
	* <p>The truth value returned by this method is equivalent to:
	* {@code getAnnotation(annotationClass) != null}
	*
	* @implSpec The default implementation returns {@code
	* getAnnotation(annotationClass) != null}.
	*
	* @param annotationClass the Class object corresponding to the
	* annotation type
	* @return true if an annotation for the specified annotation
	* type is present on this element, else false
	* @throws NullPointerException if the given annotation class is null
	* @since 1.5
	*/
	default boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) {
	return getAnnotation(annotationClass) != null;
	}

	/**
	* Returns this element's annotation for the specified type if
	* such an annotation is <em>present</em>, else null.
	*
	* @param <T> the type of the annotation to query for and return if present
	* @param annotationClass the Class object corresponding to the
	* annotation type
	* @return this element's annotation for the specified annotation type if
	* present on this element, else null
	* @throws NullPointerException if the given annotation class is null
	* @since 1.5
	*/
	<T extends Annotation> T getAnnotation(Class<T> annotationClass);

	/**
	* Returns annotations that are <em>present</em> on this element.
	*
	* If there are no annotations <em>present</em> on this element, the return
	* value is an array of length 0.
	*
	* The caller of this method is free to modify the returned array; it will
	* have no effect on the arrays returned to other callers.
	*
	* @return annotations present on this element
	* @since 1.5
	*/
	Annotation[] getAnnotations();

	/**
	* Returns annotations that are <em>associated</em> with this element.
	*
	* If there are no annotations <em>associated</em> with this element, the return
	* value is an array of length 0.
	*
	* The difference between this method and {@link #getAnnotation(Class)}
	* is that this method detects if its argument is a <em>repeatable
	* annotation type</em> (JLS {@jls 9.6}), and if so, attempts to find one or
	* more annotations of that type by "looking through" a container
	* annotation.
	*
	* The caller of this method is free to modify the returned array; it will
	* have no effect on the arrays returned to other callers.
	*
	* @implSpec The default implementation first calls {@link
	* #getDeclaredAnnotationsByType(Class)} passing {@code
	* annotationClass} as the argument. If the returned array has
	* length greater than zero, the array is returned. If the returned
	* array is zero-length and this {@code AnnotatedElement} is a
	* class and the argument type is an inheritable annotation type,
	* and the superclass of this {@code AnnotatedElement} is non-null,
	* then the returned result is the result of calling {@link
	* #getAnnotationsByType(Class)} on the superclass with {@code
	* annotationClass} as the argument. Otherwise, a zero-length
	* array is returned.
	*
	* @param <T> the type of the annotation to query for and return if present
	* @param annotationClass the Class object corresponding to the
	* annotation type
	* @return all this element's annotations for the specified annotation type if
	* associated with this element, else an array of length zero
	* @throws NullPointerException if the given annotation class is null
	* @since 1.8
	*/
	default <T extends Annotation> T[] getAnnotationsByType(Class<T> annotationClass) {
	/*
	* Definition of associated: directly or indirectly present OR
	* neither directly nor indirectly present AND the element is
	* a Class, the annotation type is inheritable, and the
	* annotation type is associated with the superclass of the
	* element.
	*/
	T[] result = getDeclaredAnnotationsByType(annotationClass);

	if (result.length == 0 && // Neither directly nor indirectly present
	this instanceof Class && // the element is a class
	AnnotationType.getInstance(annotationClass).isInherited()) { // Inheritable
	Class<?> superClass = ((Class<?>) this).getSuperclass();
	if (superClass != null) {
	// Determine if the annotation is associated with the
	// superclass
	result = superClass.getAnnotationsByType(annotationClass);
	}
	}

	return result;
	}

	/**
	* Returns this element's annotation for the specified type if
	* such an annotation is <em>directly present</em>, else null.
	*
	* This method ignores inherited annotations. (Returns null if no
	* annotations are directly present on this element.)
	*
	* @implSpec The default implementation first performs a null check
	* and then loops over the results of {@link
	* #getDeclaredAnnotations} returning the first annotation whose
	* annotation type matches the argument type.
	*
	* @param <T> the type of the annotation to query for and return if directly present
	* @param annotationClass the Class object corresponding to the
	* annotation type
	* @return this element's annotation for the specified annotation type if
	* directly present on this element, else null
	* @throws NullPointerException if the given annotation class is null
	* @since 1.8
	*/
	default <T extends Annotation> T getDeclaredAnnotation(Class<T> annotationClass) {
	Objects.requireNonNull(annotationClass);
	// Loop over all directly-present annotations looking for a matching one
	for (Annotation annotation : getDeclaredAnnotations()) {
	if (annotationClass.equals(annotation.annotationType())) {
	// More robust to do a dynamic cast at runtime instead
	// of compile-time only.
	return annotationClass.cast(annotation);
	}
	}
	return null;
	}

	/**
	* Returns this element's annotation(s) for the specified type if
	* such annotations are either <em>directly present</em> or
	* <em>indirectly present</em>. This method ignores inherited
	* annotations.
	*
	* If there are no specified annotations directly or indirectly
	* present on this element, the return value is an array of length
	* 0.
	*
	* The difference between this method and {@link
	* #getDeclaredAnnotation(Class)} is that this method detects if its
	* argument is a <em>repeatable annotation type</em> (JLS {@jls 9.6}), and if so,
	* attempts to find one or more annotations of that type by "looking
	* through" a container annotation if one is present.
	*
	* The caller of this method is free to modify the returned array; it will
	* have no effect on the arrays returned to other callers.
	*
	* @implSpec The default implementation may call {@link
	* #getDeclaredAnnotation(Class)} one or more times to find a
	* directly present annotation and, if the annotation type is
	* repeatable, to find a container annotation. If annotations of
	* the annotation type {@code annotationClass} are found to be both
	* directly and indirectly present, then {@link
	* #getDeclaredAnnotations()} will get called to determine the
	* order of the elements in the returned array.
	*
	* <p>Alternatively, the default implementation may call {@link
	* #getDeclaredAnnotations()} a single time and the returned array
	* examined for both directly and indirectly present
	* annotations. The results of calling {@link
	* #getDeclaredAnnotations()} are assumed to be consistent with the
	* results of calling {@link #getDeclaredAnnotation(Class)}.
	*
	* @param <T> the type of the annotation to query for and return
	* if directly or indirectly present
	* @param annotationClass the Class object corresponding to the
	* annotation type
	* @return all this element's annotations for the specified annotation type if
	* directly or indirectly present on this element, else an array of length zero
	* @throws NullPointerException if the given annotation class is null
	* @since 1.8
	*/
	default <T extends Annotation> T[] getDeclaredAnnotationsByType(Class<T> annotationClass) {
	Objects.requireNonNull(annotationClass);
	return AnnotationSupport.
	getDirectlyAndIndirectlyPresent(Arrays.stream(getDeclaredAnnotations()).
	collect(Collectors.toMap(Annotation::annotationType,
	Function.identity(),
	((first,second) -> first),
	LinkedHashMap::new)),
	annotationClass);
	}

	/**
	* Returns annotations that are <em>directly present</em> on this element.
	* This method ignores inherited annotations.
	*
	* If there are no annotations <em>directly present</em> on this element,
	* the return value is an array of length 0.
	*
	* The caller of this method is free to modify the returned array; it will
	* have no effect on the arrays returned to other callers.
	*
	* @return annotations directly present on this element
	* @since 1.5
	*/
	Annotation[] getDeclaredAnnotations();
	}

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