scala.reflect.api

Annotations

trait Annotations extends AnyRef

EXPERIMENTAL

This trait provides annotation support for the reflection API.

The API distinguishes between two kinds of annotations:

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.

The distinction between Java and Scala annotations is manifested in the contract of scala.reflect.api.Annotations#Annotation, which exposes both scalaArgs and javaArgs. For Scala or Java annotations extending scala.annotation.ClassfileAnnotation scalaArgs is empty and arguments are stored in javaArgs. For all other Scala annotations, arguments are stored in scalaArgs and javaArgs is empty.

Arguments in scalaArgs are represented as typed trees. Note that these trees are not transformed by any phases following the type-checker. Arguments in javaArgs are repesented as a map from scala.reflect.api.Names#Name to scala.reflect.api.Annotations#JavaArgument. Instances of JavaArgument represent different kinds of Java annotation arguments:

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

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Annotations.scala
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Type Members

  1. abstract type Annotation >: Null <: Universe.AnnotationApi

    Information about an annotation.

  2. trait AnnotationApi extends AnyRef

    The API of Annotation instances.

  3. abstract class AnnotationExtractor extends AnyRef

    An extractor class to create and pattern match with syntax Annotation(tpe, scalaArgs, javaArgs).

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

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

  5. trait ArrayArgumentApi extends AnyRef

    API of ArrayArgument instances.

  6. abstract class ArrayArgumentExtractor extends AnyRef

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

  7. abstract type JavaArgument >: Null <: AnyRef

    A Java annotation argument

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

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

  9. trait LiteralArgumentApi extends AnyRef

    The API of LiteralArgument instances.

  10. abstract class LiteralArgumentExtractor extends AnyRef

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

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

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

  12. trait NestedArgumentApi extends AnyRef

    API of NestedArgument instances.

  13. abstract class NestedArgumentExtractor extends AnyRef

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

Abstract Value Members

  1. abstract val Annotation: Universe.AnnotationExtractor

    The constructor/extractor for Annotation instances.

  2. implicit abstract val AnnotationTag: ClassTag[Universe.Annotation]

    A tag that preserves the identity of the Annotation abstract type from erasure.

    A tag that preserves the identity of the Annotation abstract type from erasure. Can be used for pattern matching, instance tests, serialization and likes.

  3. abstract val ArrayArgument: Universe.ArrayArgumentExtractor

    The constructor/extractor for ArrayArgument instances.

  4. implicit abstract val ArrayArgumentTag: ClassTag[Universe.ArrayArgument]

    A tag that preserves the identity of the ArrayArgument abstract type from erasure.

    A tag that preserves the identity of the ArrayArgument abstract type from erasure. Can be used for pattern matching, instance tests, serialization and likes.

  5. implicit abstract val JavaArgumentTag: ClassTag[Universe.JavaArgument]

    A tag that preserves the identity of the JavaArgument abstract type from erasure.

    A tag that preserves the identity of the JavaArgument abstract type from erasure. Can be used for pattern matching, instance tests, serialization and likes.

  6. abstract val LiteralArgument: Universe.LiteralArgumentExtractor

    The constructor/extractor for LiteralArgument instances.

  7. implicit abstract val LiteralArgumentTag: ClassTag[Universe.LiteralArgument]

    A tag that preserves the identity of the LiteralArgument abstract type from erasure.

    A tag that preserves the identity of the LiteralArgument abstract type from erasure. Can be used for pattern matching, instance tests, serialization and likes.

  8. abstract val NestedArgument: Universe.NestedArgumentExtractor

    The constructor/extractor for NestedArgument instances.

  9. implicit abstract val NestedArgumentTag: ClassTag[Universe.NestedArgument]

    A tag that preserves the identity of the NestedArgument abstract type from erasure.

    A tag that preserves the identity of the NestedArgument abstract type from erasure. Can be used for pattern matching, instance tests, serialization and likes.

Concrete Value Members

  1. final def !=(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  2. final def !=(arg0: Any): Boolean

    Test two objects for inequality.

    Test two objects for inequality.

    returns

    true if !(this == that), false otherwise.

    Definition Classes
    Any
  3. 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
  4. def +(other: String): String

    Implicit information
    This member is added by an implicit conversion from Annotations to StringAdd performed by method any2stringadd in scala.Predef.
    Definition Classes
    StringAdd
  5. def ->[B](y: B): (Annotations, B)

    Implicit information
    This member is added by an implicit conversion from Annotations to ArrowAssoc[Annotations] performed by method any2ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  6. final def ==(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  7. final def ==(arg0: Any): Boolean

    Test two objects for equality.

    Test two objects for equality. 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
    Any
  8. 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.

  9. 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

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

    Implicit information
    This member is added by an implicit conversion from Annotations to Ensuring[Annotations] performed by method any2Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def ensuring(cond: (Annotations) ⇒ Boolean): Annotations

    Implicit information
    This member is added by an implicit conversion from Annotations to Ensuring[Annotations] performed by method any2Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  12. def ensuring(cond: Boolean, msg: ⇒ Any): Annotations

    Implicit information
    This member is added by an implicit conversion from Annotations to Ensuring[Annotations] performed by method any2Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. def ensuring(cond: Boolean): Annotations

    Implicit information
    This member is added by an implicit conversion from Annotations to Ensuring[Annotations] performed by method any2Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  14. final def eq(arg0: AnyRef): Boolean

    Tests whether the argument (arg0) is a reference to the receiver object (this).

    Tests whether the argument (arg0) 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
  15. 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
  16. 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

  17. def formatted(fmtstr: String): String

    Returns string formatted according to given format string.

    Returns string formatted according to given format string. Format strings are as for String.format (@see java.lang.String.format).

    Implicit information
    This member is added by an implicit conversion from Annotations to StringFormat performed by method any2stringfmt in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  18. final def getClass(): Class[_]

    A representation that corresponds to the dynamic class of the receiver object.

    A representation that corresponds to the dynamic class of the receiver object.

    The nature of the representation is platform dependent.

    returns

    a representation that corresponds to the dynamic class of the receiver object.

    Definition Classes
    AnyRef → Any
    Note

    not specified by SLS as a member of AnyRef

  19. 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
  20. 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
  21. 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
  22. 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

  23. 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

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

    Definition Classes
    AnyRef
  25. 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
  26. final def wait(): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  27. final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  28. final def wait(arg0: Long): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  29. def [B](y: B): (Annotations, B)

    Implicit information
    This member is added by an implicit conversion from Annotations to ArrowAssoc[Annotations] performed by method any2ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Shadowed Implicit Value Members

  1. val self: Any

    Implicit information
    This member is added by an implicit conversion from Annotations to StringAdd performed by method any2stringadd in scala.Predef.
    Shadowing
    This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
    To access this member you can use a type ascription:
    (annotations: StringAdd).self
    Definition Classes
    StringAdd
  2. val self: Any

    Implicit information
    This member is added by an implicit conversion from Annotations to StringFormat performed by method any2stringfmt in scala.Predef.
    Shadowing
    This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
    To access this member you can use a type ascription:
    (annotations: StringFormat).self
    Definition Classes
    StringFormat

Deprecated Value Members

  1. def x: Annotations

    Implicit information
    This member is added by an implicit conversion from Annotations to ArrowAssoc[Annotations] performed by method any2ArrowAssoc in scala.Predef.
    Shadowing
    This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
    To access this member you can use a type ascription:
    (annotations: ArrowAssoc[Annotations]).x
    Definition Classes
    ArrowAssoc
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) Use leftOfArrow instead

  2. def x: Annotations

    Implicit information
    This member is added by an implicit conversion from Annotations to Ensuring[Annotations] performed by method any2Ensuring in scala.Predef.
    Shadowing
    This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
    To access this member you can use a type ascription:
    (annotations: Ensuring[Annotations]).x
    Definition Classes
    Ensuring
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) Use resultOfEnsuring instead

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from Annotations to StringAdd

Inherited by implicit conversion any2stringfmt from Annotations to StringFormat

Inherited by implicit conversion any2ArrowAssoc from Annotations to ArrowAssoc[Annotations]

Inherited by implicit conversion any2Ensuring from Annotations to Ensuring[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.

Tags

Implicit values that provide ClassTags for the reflection classes. These are abstract in the interface but are later filled in to provide ClassTags for the either the runtime reflection or macros entities, depending on the use.

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