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.
- Scala annotations: annotations on definitions or types produced by the Scala compiler.
When a Scala annotation that inherits from scala.annotation.StaticAnnotation 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
- Grouped
- Alphabetic
- By Inheritance
- Annotations
- AnyRef
- Any
- by any2stringadd
- by StringFormat
- by Ensuring
- by ArrowAssoc
- Hide All
- Show All
- Public
- Protected
Type Members
- abstract type Annotation >: Null <: Universe.AnnotationApi
Information about an annotation.
- trait AnnotationApi extends AnyRef
The API of
Annotationinstances.The API of
Annotationinstances. 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).An extractor class to create and pattern match with syntax
Annotation(tpe, scalaArgs, javaArgs). Here,tpeis the annotation type,scalaArgsthe payload of Scala annotations, andjavaArgsthe payload of Java annotations.
Deprecated Type Members
- abstract type JavaArgument >: Null <: Universe.JavaArgumentApi
A Java annotation argument
A Java annotation argument
- Annotations
- @deprecated
- Deprecated
(Since version 2.11.0) use
Annotation.treeto inspect annotation arguments
- trait JavaArgumentApi extends AnyRef
Has no special methods.
Has no special methods. Is here to provides erased identity for
CompoundType.- Annotations
- @deprecated
- Deprecated
(Since version 2.11.0) use
Annotation.treeto inspect annotation arguments
Abstract Value Members
- abstract val Annotation: Universe.AnnotationExtractor
The constructor/extractor for
Annotationinstances. - abstract def annotationToTree(ann: Universe.Annotation): Universe.Tree
- Attributes
- protected[scala]
- abstract def treeToAnnotation(tree: Universe.Tree): Universe.Annotation
- Attributes
- protected[scala]
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 toany2stringadd[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 toArrowAssoc[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(classOf[java.lang.CloneNotSupportedException]) @native()
- def ensuring(cond: (Annotations) => Boolean, msg: => Any): Annotations
- Implicit
- This member is added by an implicit conversion from Annotations toEnsuring[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 toEnsuring[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 toEnsuring[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 toEnsuring[Annotations] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- final def eq(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- def equals(arg0: AnyRef): 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 toStringFormat[Annotations] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @inline()
- final def getClass(): Class[_ <: AnyRef]
- 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(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException]) @native()
Deprecated Value Members
- def →[B](y: B): (Annotations, B)
- Implicit
- This member is added by an implicit conversion from Annotations toArrowAssoc[Annotations] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use
->instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.
Inherited from AnyRef
Inherited from Any
Inherited by implicit conversion any2stringadd fromAnnotations to any2stringadd[Annotations]
Inherited by implicit conversion StringFormat fromAnnotations to StringFormat[Annotations]
Inherited by implicit conversion Ensuring fromAnnotations to Ensuring[Annotations]
Inherited by implicit conversion ArrowAssoc fromAnnotations to ArrowAssoc[Annotations]
Annotations
API
The methods available for each reflection entity, without the implementation. Since the reflection entities are later overridden by runtime reflection and macros, their API counterparts guarantee a minimum set of methods that are implemented.
Extractors
Extractors provide the machinery necessary to allow pattern matching and construction of reflection entities that is similar to case classes, although the entities are only abstract types that are later overridden.