Scala Reflection Library2.12.21 < Back
 

# Packages

-  package root
  Definition Classes
    root
-  package scala
  Definition Classes
    root
-  package reflect
  Definition Classes
    scala
-  package api

  EXPERIMENTAL

  EXPERIMENTAL

  The Scala Reflection API (located in scala-reflect.jar).

  In Scala 2.10.0, the Scala Reflection API and its implementation have an "experimental" status. This means that the API and the docs are not complete and can be changed in binary- and source-incompatible manner in 2.10.1. This also means that the implementation has some known issues.

  The following types are the backbone of the Scala Reflection API, and serve as a good starting point for information about Scala Reflection:

  - scala.reflect.api.Symbols
  - scala.reflect.api.Types
  - scala.reflect.api.Mirrors
  - scala.reflect.api.Universe

  For more information about Scala Reflection, see the Reflection Guide

  Definition Classes
    reflect
-  trait Mirrors extends AnyRef

  EXPERIMENTAL

  EXPERIMENTAL

  This trait provides support for Mirrors in the Scala Reflection API.

  `Mirror`s are a central part of Scala Reflection. All information provided by reflection is made accessible through `Mirror`s. Depending on the type of information to be obtained, or the reflective action to be taken, different flavors of mirrors must be used. "Classloader" mirrors can be used to obtain representations of types and members. From a classloader `Mirror`, it's possible to obtain more specialized "invoker" `Mirror`s (the most commonly-used mirrors), which implement reflective invocations, such as method/constructor calls and field accesses.

  The two flavors of mirrors:

  - “Classloader” mirrors. These mirrors translate names to symbols (via methods `staticClass`/`staticModule`/`staticPackage`).
  - "Invoker” mirrors. These mirrors implement reflective invocations (via methods `MethodMirror.apply`, `FieldMirror.get`, etc). These "invoker" mirrors are the types of mirrors that are most commonly used.

  ##### Compile-time Mirrors

  Compile-time `Mirror`s make use of only classloader `Mirror`s to load `Symbol`s by name.

  The entry point to classloader `Mirror`s is via scala.reflect.macros.blackbox.Context#mirror or scala.reflect.macros.whitebox.Context#mirror. Typical methods which use classloader `Mirror`s include scala.reflect.api.Mirror#staticClass, scala.reflect.api.Mirror#staticModule, and scala.reflect.api.Mirror#staticPackage. For example:

      import scala.reflect.macros.blackbox.Context

      case class Location(filename: String, line: Int, column: Int)

      object Macros {
        def currentLocation: Location = macro impl

        def impl(c: Context): c.Expr[Location] = {
          import c.universe._
          val pos = c.macroApplication.pos
          val clsLocation = c.mirror.staticModule("Location") // get symbol of "Location" object
          c.Expr(Apply(Ident(clsLocation), List(Literal(Constant(pos.source.path)), Literal(Constant(pos.line)), Literal(Constant(pos.column)))))
        }
      }

  Of Note: There are several high-level alternatives that one can use to avoid having to manually lookup symbols. For example, `typeOf[Location.type].termSymbol` (or `typeOf[Location].typeSymbol` if we needed a `ClassSymbol`), which are type safe since we don’t have to use `String`s to lookup the `Symbol`.

  ##### Runtime Mirrors

  Runtime `Mirror`s make use of both classloader and invoker `Mirror`s.

  The entry point to `Mirror`s for use at runtime is via `ru.runtimeMirror(<classloader>)`, where `ru` is scala.reflect.runtime.universe.

  The result of a scala.reflect.api.JavaUniverse#runtimeMirror call is a classloader mirror, of type scala.reflect.api.Mirrors#ReflectiveMirror, which can load symbols by names as discussed above (in the “Compile-time” section).

  A classloader mirror can create invoker mirrors, which include: scala.reflect.api.Mirrors#InstanceMirror, scala.reflect.api.Mirrors#MethodMirror, scala.reflect.api.Mirrors#FieldMirror, scala.reflect.api.Mirrors#ClassMirror and scala.reflect.api.Mirrors#ModuleMirror.

  Examples of how these two types of `Mirror`s interact are available below.

  ##### Types of Mirrors, Their Use Cases & Examples

  scala.reflect.api.Mirrors#ReflectiveMirror. Used for loading `Symbol`s by name, and as an entry point into invoker mirrors. Entry point: `val m = ru.runtimeMirror(<classloader>)`. Example:

      scala> val ru = scala.reflect.runtime.universe
      ru: scala.reflect.api.JavaUniverse = ...

      scala> val m = ru.runtimeMirror(getClass.getClassLoader)
      m: reflect.runtime.universe.Mirror = JavaMirror ...

  scala.reflect.api.Mirrors#InstanceMirror. Used for creating invoker `Mirror`s for methods and fields and for inner classes and inner objects (modules). Entry point: `val im = m.reflect(<value>)`. Example:

      scala> class C { def x = 2 }
      defined class C

      scala> val im = m.reflect(new C)
      im: reflect.runtime.universe.InstanceMirror = instance mirror for C@3442299e

  scala.reflect.api.Mirrors#MethodMirror. Used for invoking instance methods (Scala only has instance methods-- methods of objects are instance methods of object instances, obtainable via `ModuleMirror.instance`). Entry point: `val mm = im.reflectMethod(<method symbol>)`. Example:

      scala> val methodX = typeOf[C].declaration(TermName("x")).asMethod
      methodX: reflect.runtime.universe.MethodSymbol = method x

      scala> val mm = im.reflectMethod(methodX)
      mm: reflect.runtime.universe.MethodMirror = method mirror for C.x: scala.Int (bound to C@3442299e)

      scala> mm()
      res0: Any = 2

  scala.reflect.api.Mirrors#FieldMirror. Used for getting/setting instance fields (Scala only has instance fields-- fields of objects are instance methods of object instances obtainable via ModuleMirror.instance). Entry point: `val fm = im.reflectMethod(<field or accessor symbol>)`. Example:

      scala> class C { val x = 2; val y = 3 }
      defined class C

      scala> val m = ru.runtimeMirror(getClass.getClassLoader)
      m: reflect.runtime.universe.Mirror = JavaMirror ...

      scala> val im = m.reflect(new C)
      im: reflect.runtime.universe.InstanceMirror = instance mirror for C@5f0c8ac1

      scala> val fieldX = typeOf[C].declaration(TermName("x")).asTerm.accessed.asTerm
      fieldX: reflect.runtime.universe.TermSymbol = value x
      scala> val fmX = im.reflectField(fieldX)
      fmX: reflect.runtime.universe.FieldMirror = field mirror for C.x (bound to C@5f0c8ac1)

      scala> fmX.get
      res0: Any = 2

      scala> fmX.set(3) // NOTE: can set an underlying value of an immutable field!

      scala> val fieldY = typeOf[C].declaration(TermName("y")).asTerm.accessed.asTerm
      fieldY: reflect.runtime.universe.TermSymbol = variable y

      scala> val fmY = im.reflectField(fieldY)
      fmY: reflect.runtime.universe.FieldMirror = field mirror for C.y (bound to C@5f0c8ac1)

      scala> fmY.get
      res1: Any = 3

      scala> fmY.set(4)

      scala> fmY.get
      res2: Any = 4

  scala.reflect.api.Mirrors#ClassMirror. Used for creating invoker mirrors for constructors. Entry points: for static classes `val cm1 = m.reflectClass(<class symbol>)`, for inner classes `val mm2 = im.reflectClass(<class symbol>)`. Example:

      scala> case class C(x: Int)
      defined class C

      scala> val m = ru.runtimeMirror(getClass.getClassLoader)
      m: reflect.runtime.universe.Mirror = JavaMirror ...

      scala> val classC = typeOf[C].typeSymbol.asClass

      classC: reflect.runtime.universe.Symbol = class C

      scala> val cm = m.reflectClass(classC)
      cm: reflect.runtime.universe.ClassMirror = class mirror for C (bound to null)

      scala> val ctorC = typeOf[C].declaration(ru.nme.CONSTRUCTOR).asMethod
      ctorC: reflect.runtime.universe.MethodSymbol = constructor C

      scala> val ctorm = cm.reflectConstructor(ctorC)
      ctorm: reflect.runtime.universe.MethodMirror = constructor mirror for C.<init>(x: scala.Int): C (bound to null)

      scala> ctorm(2)
      res0: Any = C(2)

  scala.reflect.api.Mirrors#ModuleMirror. Used for getting singleton instances of objects. Entry points: for static objects (modules) `val mm1 = m.reflectModule(<module symbol>)`, for inner objects (modules) `val mm2 = im.reflectModule(<module symbol>)`. Example:

      scala> object C { def x = 2 }
      defined module C

      scala> val m = ru.runtimeMirror(getClass.getClassLoader)
      m: reflect.runtime.universe.Mirror = JavaMirror ...

      scala> val objectC = typeOf[C.type].termSymbol.asModule
      objectC: reflect.runtime.universe.ModuleSymbol = object C

      scala> val mm = m.reflectModule(objectC)
      mm: reflect.runtime.universe.ModuleMirror = module mirror for C (bound to null)

      scala> val obj = mm.instance
      obj: Any = C$@1005ec04

  For more information about `Mirrors`s, see the Reflection Guide: Mirrors

  Definition Classes
    api
- ClassMirror
- FieldMirror
- InstanceMirror
- MethodMirror
- Mirror
- ModuleMirror
- ReflectiveMirror
- RuntimeClass
- RuntimeClassApi
- RuntimeMirror
- TemplateMirror

t

scala.reflect.api.Mirrors

# ClassMirror 

###

#### trait ClassMirror extends Universe.TemplateMirror

A mirror that reflects the instance parts of a runtime class. See the overview page for details on how to use runtime reflection.

Source
  Mirrors.scala

Linear Supertypes
Universe.TemplateMirror, AnyRef, Any
 
Ordering

1. Alphabetic
2. By Inheritance

Inherited

1. ClassMirror
2. TemplateMirror
3. AnyRef
4. Any

Implicitly

1. by any2stringadd
2. by StringFormat
3. by Ensuring
4. by ArrowAssoc

1. Hide All
2. Show All

Visibility

1. Public
2. All

### Abstract Value Members

1.  abstract def isStatic: Boolean

   True if the mirror represents the static part of a runtime class or the companion object of a Scala class.

   True if the mirror represents the static part of a runtime class or the companion object of a Scala class. One has:

   this.isStatic == this.isInstanceOf[ModuleMirror] !this.isStatic == this.isInstanceOf[ClassMirror]

   Definition Classes
     TemplateMirror
2.  abstract def reflectConstructor(constructor: Universe.MethodSymbol): Universe.MethodMirror

   Reflects against a constructor symbol and returns a mirror that can be used to invoke it and construct instances of this mirror's symbols.

   Reflects against a constructor symbol and returns a mirror that can be used to invoke it and construct instances of this mirror's symbols.

   To get a constructor symbol you would like to reflect, use `<this mirror>.symbol.info.member(termNames.CONSTRUCTOR).asMethod`. For further information about member lookup refer to `Symbol.info`.

   The input symbol can be either private or non-private (Scala reflection transparently deals with visibility). It must be a member (declared or inherited) of the class underlying this mirror.

3.  abstract def symbol: Universe.ClassSymbol

   The Scala class symbol corresponding to the reflected class

   The Scala class symbol corresponding to the reflected class

   Definition Classes
     ClassMirror → TemplateMirror

### Concrete Value Members

1.  final def !=(arg0: Any): Boolean
   Definition Classes
     AnyRef → Any
2.  final def ##(): Int
   Definition Classes
     AnyRef → Any
3.  def +(other: String): String
   Implicit
     This member is added by an implicit conversion from Universe.ClassMirror to any2stringadd[Universe.ClassMirror] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd
4.  def ->[B](y: B): (Universe.ClassMirror, B)
   Implicit
     This member is added by an implicit conversion from Universe.ClassMirror to ArrowAssoc[Universe.ClassMirror] performed by method ArrowAssoc in scala.Predef.
   Definition Classes
     ArrowAssoc
   Annotations
     @inline()
5.  final def ==(arg0: Any): Boolean
   Definition Classes
     AnyRef → Any
6.  final def asInstanceOf[T0]: T0
   Definition Classes
     Any
7.  def clone(): AnyRef
   Attributes
     protected[lang]
   Definition Classes
     AnyRef
   Annotations
     @throws( ... ) @native()
8.  def ensuring(cond: (Universe.ClassMirror) ⇒ Boolean, msg: ⇒ Any): Universe.ClassMirror
   Implicit
     This member is added by an implicit conversion from Universe.ClassMirror to Ensuring[Universe.ClassMirror] performed by method Ensuring in scala.Predef.
   Definition Classes
     Ensuring
9.  def ensuring(cond: (Universe.ClassMirror) ⇒ Boolean): Universe.ClassMirror
   Implicit
     This member is added by an implicit conversion from Universe.ClassMirror to Ensuring[Universe.ClassMirror] performed by method Ensuring in scala.Predef.
   Definition Classes
     Ensuring
10.  def ensuring(cond: Boolean, msg: ⇒ Any): Universe.ClassMirror
    Implicit
      This member is added by an implicit conversion from Universe.ClassMirror to Ensuring[Universe.ClassMirror] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
11.  def ensuring(cond: Boolean): Universe.ClassMirror
    Implicit
      This member is added by an implicit conversion from Universe.ClassMirror to Ensuring[Universe.ClassMirror] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
12.  final def eq(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
13.  def equals(arg0: Any): Boolean
    Definition Classes
      AnyRef → Any
14.  def finalize(): Unit
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )
15.  final def getClass(): Class[_]
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
16.  def hashCode(): Int
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
17.  final def isInstanceOf[T0]: Boolean
    Definition Classes
      Any
18.  final def ne(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
19.  final def notify(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
20.  final def notifyAll(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
21.  final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
      AnyRef
22.  def toString(): String
    Definition Classes
      AnyRef → Any
23.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
24.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
25.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... ) @native()
26.  def →[B](y: B): (Universe.ClassMirror, B)
    Implicit
      This member is added by an implicit conversion from Universe.ClassMirror to ArrowAssoc[Universe.ClassMirror] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc

### Deprecated Value Members

1.  def formatted(fmtstr: String): String
   Implicit
     This member is added by an implicit conversion from Universe.ClassMirror to StringFormat[Universe.ClassMirror] performed by method StringFormat in scala.Predef.
   Definition Classes
     StringFormat
   Annotations
     @deprecated @inline()
   Deprecated

     (Since version 2.12.16) Use `formatString.format(value)` instead of `value.formatted(formatString)`, or use the `f""` string interpolator. In Java 15 and later, `formatted` resolves to the new method in String which has reversed parameters.

### Inherited from Universe.TemplateMirror

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion any2stringadd from Universe.ClassMirror to any2stringadd[Universe.ClassMirror]

### Inherited by implicit conversion StringFormat from Universe.ClassMirror to StringFormat[Universe.ClassMirror]

### Inherited by implicit conversion Ensuring from Universe.ClassMirror to Ensuring[Universe.ClassMirror]

### Inherited by implicit conversion ArrowAssoc from Universe.ClassMirror to ArrowAssoc[Universe.ClassMirror]

### Ungrouped