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 subclass to every Java annotation.
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

AnyRef, Any

Known Subclasses

JavaUniverse, Universe, Universe

Type Hierarchy

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Annotations
AnyRef
Any

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by any2stringadd
by StringFormat
by Ensuring
by ArrowAssoc

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Type Members

abstract type Annotation >: Null <: Universe.AnnotationApi
Information about an annotation.
trait AnnotationApi extends AnyRef
The API of Annotation instances.
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).
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})
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.
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.
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
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.
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")
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 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.
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).
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.
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.
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
The constructor/extractor for Annotation instances.
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.
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.
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.
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
Test two objects for inequality.
Test two objects for inequality.
returns
true if !(this == that), false otherwise.

Definition Classes
AnyRef → Any
final def ##(): Int
Equivalent to x.hashCode except for boxed numeric types and null.
Equivalent to x.hashCode except for boxed numeric types and null. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For null returns a hashcode where null.hashCode throws a NullPointerException.
returns
a hash value consistent with ==

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
The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).
The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).
returns
true if the receiver object is equivalent to the argument; false otherwise.

Definition Classes
AnyRef → Any
final def asInstanceOf[T0]: T0
Cast the receiver object to be of type T0.
Cast the receiver object to be of type T0.
Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expression List(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.
returns
the receiver object.

Definition Classes
Any
Exceptions thrown
ClassCastException if the receiver object is not an instance of the erasure of type T0.
def clone(): AnyRef
Create a copy of the receiver object.
Create a copy of the receiver object.
The default implementation of the clone method is platform dependent.
returns
a copy of the receiver object.

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
Note
not specified by SLS as a member of AnyRef
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
Tests whether the argument (that) is a reference to the receiver object (this).
Tests whether the argument (that) is a reference to the receiver object (this).
The eq method implements an equivalence relation on non-null instances of AnyRef, and has three additional properties:
- It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false.
- For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false.
- null.eq(null) returns true.
When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).
returns
true if the argument is a reference to the receiver object; false otherwise.

Definition Classes
AnyRef
def equals(arg0: Any): Boolean
The equality method for reference types.
The equality method for reference types. Default implementation delegates to eq.
See also equals in scala.Any.
returns
true if the receiver object is equivalent to the argument; false otherwise.

Definition Classes
AnyRef → Any
def finalize(): Unit
Called by the garbage collector on the receiver object when there are no more references to the object.
Called by the garbage collector on the receiver object when there are no more references to the object.
The details of when and if the finalize method is invoked, as well as the interaction between finalize and non-local returns and exceptions, are all platform dependent.

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
Note
not specified by SLS as a member of AnyRef
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[_]
Returns the runtime class representation of the object.
Returns the runtime class representation of the object.
returns
a class object corresponding to the runtime type of the receiver.

Definition Classes
AnyRef → Any
def hashCode(): Int
The hashCode method for reference types.
The hashCode method for reference types. See hashCode in scala.Any.
returns
the hash code value for this object.

Definition Classes
AnyRef → Any
final def isInstanceOf[T0]: Boolean
Test whether the dynamic type of the receiver object is T0.
Test whether the dynamic type of the receiver object is T0.
Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression 1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.
returns
true if the receiver object is an instance of erasure of type T0; false otherwise.

Definition Classes
Any
final def ne(arg0: AnyRef): Boolean
Equivalent to !(this eq that).
Equivalent to !(this eq that).
returns
true if the argument is not a reference to the receiver object; false otherwise.

Definition Classes
AnyRef
final def notify(): Unit
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up a single thread that is waiting on the receiver object's monitor.

Definition Classes
AnyRef
Note
not specified by SLS as a member of AnyRef
final def notifyAll(): Unit
Wakes up all threads that are waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.

Definition Classes
AnyRef
Note
not specified by SLS as a member of AnyRef
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
def toString(): String
Creates a String representation of this object.
Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.
returns
a String representation of the object.

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( ... )
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

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from Annotations to any2stringadd[Annotations]

Inherited by implicit conversion StringFormat from Annotations to StringFormat[Annotations]

Inherited by implicit conversion Ensuring from Annotations to Ensuring[Annotations]

Inherited by implicit conversion ArrowAssoc from Annotations 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.

Packages

Annotations

trait Annotations extends AnyRef

Type Members

Abstract Value Members

Concrete Value Members

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from Annotations to any2stringadd[Annotations]

Inherited by implicit conversion StringFormat from Annotations to StringFormat[Annotations]

Inherited by implicit conversion Ensuring from Annotations to Ensuring[Annotations]

Inherited by implicit conversion ArrowAssoc from Annotations to ArrowAssoc[Annotations]

Annotations

API

Extractors

Ungrouped

Packages

Annotations 

trait Annotations extends AnyRef

Type Members

Abstract Value Members

Concrete Value Members

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from Annotations to any2stringadd[Annotations]

Inherited by implicit conversion StringFormat from Annotations to StringFormat[Annotations]

Inherited by implicit conversion Ensuring from Annotations to Ensuring[Annotations]

Inherited by implicit conversion ArrowAssoc from Annotations to ArrowAssoc[Annotations]

Annotations

API

Extractors

Ungrouped

Annotations