Trait scala.reflect.api.Annotations

trait Annotations extends AnyRef

EXPERIMENTAL

This trait provides annotation support for the reflection API.

In Scala, annotations belong to one of the two categories:

  • Java annotations: annotations on definitions produced by the Java compiler, i.e., subtypes of java.lang.annotation.Annotation attached to program definitions. When read by Scala reflection, the scala.annotation.ClassfileAnnotation trait is automatically added as a superclass to every Java annotation type.
  • Scala annotations: annotations on definitions or types produced by the Scala compiler.

When a Scala annotation that inherits from scala.annotation.StaticAnnotation or scala.annotation.ClassfileAnnotation is compiled, it is stored as special attributes in the corresponding classfile, and not as a Java annotation. Note that subclassing just scala.annotation.Annotation is not enough to have the corresponding metadata persisted for runtime reflection.

Both Java and Scala annotations are represented as typed trees carrying constructor invocations corresponding to the annotation. For instance, the annotation in @ann(1, 2) class C is represented as q"@new ann(1, 2)".

Unlike Java reflection, Scala reflection does not support evaluation of constructor invocations stored in annotations into underlying objects. For instance it's impossible to go from @ann(1, 2) class C to ann(1, 2), so one has to analyze trees representing annotation arguments to manually extract corresponding values. Towards that end, arguments of an annotation can be obtained via annotation.tree.children.tail.

For more information about Annotations, see the Reflection Guide: Annotations, Names, Scopes, and More

Self Type
Universe
Source
Annotations.scala
Linear Supertypes
Known Subclasses

Type Members

abstract type Annotation >: Null <: Universe.AnnotationApi

trait AnnotationApi extends AnyRef

The API of Annotation instances. The main source of information about annotations is the scala.reflect.api.Annotations page.

abstract class AnnotationExtractor extends AnyRef

An extractor class to create and pattern match with syntax Annotation(tpe, scalaArgs, javaArgs). Here, tpe is the annotation type, scalaArgs the payload of Scala annotations, and javaArgs the payload of Java annotations.

abstract type ArrayArgument >: Null <: Universe.ArrayArgumentApi with Universe.JavaArgument

An array argument to a Java annotation as in @Target(value={TYPE,FIELD,METHOD,PARAMETER})

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

trait ArrayArgumentApi extends AnyRef

API of ArrayArgument instances. The main source of information about annotations is the scala.reflect.api.Annotations page.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

abstract class ArrayArgumentExtractor extends AnyRef

An extractor class to create and pattern match with syntax ArrayArgument(args) where args is the argument array.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

abstract type JavaArgument >: Null <: Universe.JavaArgumentApi

A Java annotation argument

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

trait JavaArgumentApi extends AnyRef

Has no special methods. Is here to provides erased identity for CompoundType.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

abstract type LiteralArgument >: Null <: Universe.LiteralArgumentApi with Universe.JavaArgument

A literal argument to a Java annotation as "use X instead" in @Deprecated("use X instead")

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

trait LiteralArgumentApi extends AnyRef

The API of LiteralArgument instances. The main source of information about annotations is the scala.reflect.api.Annotations page.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

abstract class LiteralArgumentExtractor extends AnyRef

An extractor class to create and pattern match with syntax LiteralArgument(value) where value is the constant argument.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

abstract type NestedArgument >: Null <: Universe.NestedArgumentApi with Universe.JavaArgument

A nested annotation argument to a Java annotation as @Nested in @Outer(@Nested).

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

trait NestedArgumentApi extends AnyRef

API of NestedArgument instances. The main source of information about annotations is the scala.reflect.api.Annotations page.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

abstract class NestedArgumentExtractor extends AnyRef

An extractor class to create and pattern match with syntax NestedArgument(annotation) where annotation is the nested annotation.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

Abstract Value Members

abstract val Annotation: Universe.AnnotationExtractor

abstract def annotationToTree(ann: Universe.Annotation): Universe.Tree

Attributes
protected[scala]

abstract def treeToAnnotation(tree: Universe.Tree): Universe.Annotation

Attributes
protected[scala]

abstract val ArrayArgument: Universe.ArrayArgumentExtractor

The constructor/extractor for ArrayArgument instances.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

abstract val LiteralArgument: Universe.LiteralArgumentExtractor

The constructor/extractor for LiteralArgument instances.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

abstract val NestedArgument: Universe.NestedArgumentExtractor

The constructor/extractor for NestedArgument instances.

Annotations
@deprecated
Deprecated

(Since version 2.11.0) use Annotation.tree to inspect annotation arguments

Concrete Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any

final def ##(): Int

Definition Classes
AnyRef → Any

def +(other: String): String

Implicit
This member is added by an implicit conversion from Annotations to any2stringadd[Annotations] performed by method any2stringadd in scala.Predef.
Definition Classes
any2stringadd

def ->[B](y: B): (Annotations, B)

Implicit
This member is added by an implicit conversion from Annotations to ArrowAssoc[Annotations] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
@inline()

final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any

final def asInstanceOf[T0]: T0

Definition Classes
Any

def clone(): AnyRef

Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws( ... ) @native()

def ensuring(cond: (Annotations) ⇒ Boolean, msg: ⇒ Any): Annotations

Implicit
This member is added by an implicit conversion from Annotations to Ensuring[Annotations] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: (Annotations) ⇒ Boolean): Annotations

Implicit
This member is added by an implicit conversion from Annotations to Ensuring[Annotations] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: Boolean, msg: ⇒ Any): Annotations

Implicit
This member is added by an implicit conversion from Annotations to Ensuring[Annotations] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: Boolean): Annotations

Implicit
This member is added by an implicit conversion from Annotations to Ensuring[Annotations] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef

def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any

def finalize(): Unit

Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )

def formatted(fmtstr: String): String

Implicit
This member is added by an implicit conversion from Annotations to StringFormat[Annotations] performed by method StringFormat in scala.Predef.
Definition Classes
StringFormat
Annotations
@inline()

final def getClass(): Class[_]

Definition Classes
AnyRef → Any
Annotations
@native()

def hashCode(): Int

Definition Classes
AnyRef → Any
Annotations
@native()

final def isInstanceOf[T0]: Boolean

Definition Classes
Any

final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef

final def notify(): Unit

Definition Classes
AnyRef
Annotations
@native()

final def notifyAll(): Unit

Definition Classes
AnyRef
Annotations
@native()

final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef

def toString(): String

Definition Classes
AnyRef → Any

final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... ) @native()

def [B](y: B): (Annotations, B)

Implicit
This member is added by an implicit conversion from Annotations to ArrowAssoc[Annotations] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc

© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.12.9/scala-reflect/scala/reflect/api/Annotations.html