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Kotlin Standard Library for JVM
There is a newer version: 2.1.0-RC
/*
 * Copyright 2010-2024 JetBrains s.r.o. and Kotlin Programming Language contributors.
 * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
 */

package kotlin.annotation

import kotlin.annotation.AnnotationTarget.*

/**
 * Contains the list of code elements which are the possible annotation targets
 */
public enum class AnnotationTarget {
    /** Class, interface or object, annotation class is also included */
    CLASS,
    /** Annotation class only */
    ANNOTATION_CLASS,
    /** Generic type parameter */
    TYPE_PARAMETER,
    /** Property */
    PROPERTY,
    /** Field, including property's backing field */
    FIELD,
    /** Local variable */
    LOCAL_VARIABLE,
    /** Value parameter of a function or a constructor */
    VALUE_PARAMETER,
    /** Constructor only (primary or secondary) */
    CONSTRUCTOR,
    /** Function (constructors are not included) */
    FUNCTION,
    /** Property getter only */
    PROPERTY_GETTER,
    /** Property setter only */
    PROPERTY_SETTER,
    /** Type usage */
    TYPE,
    /** Any expression */
    EXPRESSION,
    /** File */
    FILE,
    /** Type alias */
    @SinceKotlin("1.1")
    TYPEALIAS
}

/**
 * Contains the list of possible annotation's retentions.
 *
 * Determines how an annotation is stored in binary output.
 */
public enum class AnnotationRetention {
    /** Annotation isn't stored in binary output */
    SOURCE,
    /** Annotation is stored in binary output, but invisible for reflection */
    BINARY,
    /** Annotation is stored in binary output and visible for reflection (default retention) */
    RUNTIME
}

/**
 * This meta-annotation indicates the kinds of code elements which are possible targets of an annotation.
 *
 * If the target meta-annotation is not present on an annotation declaration, the annotation is applicable to the following elements:
 * [CLASS], [PROPERTY], [FIELD], [LOCAL_VARIABLE], [VALUE_PARAMETER], [CONSTRUCTOR], [FUNCTION], [PROPERTY_GETTER], [PROPERTY_SETTER].
 *
 * @property allowedTargets list of allowed annotation targets
 */
@Target(AnnotationTarget.ANNOTATION_CLASS)
@MustBeDocumented
public annotation class Target(vararg val allowedTargets: AnnotationTarget)

/**
 * This meta-annotation determines whether an annotation is stored in binary output and visible for reflection. By default, both are true.
 *
 * @property value necessary annotation retention (RUNTIME, BINARY or SOURCE)
 */
@Target(AnnotationTarget.ANNOTATION_CLASS)
public annotation class Retention(val value: AnnotationRetention = AnnotationRetention.RUNTIME)

/**
 * This meta-annotation determines that an annotation is applicable twice or more on a single code element
 */
@Target(AnnotationTarget.ANNOTATION_CLASS)
public annotation class Repeatable

/**
 * This meta-annotation determines that an annotation is a part of public API and therefore should be included in the generated
 * documentation for the element to which the annotation is applied.
 */
@Target(AnnotationTarget.ANNOTATION_CLASS)
public annotation class MustBeDocumented