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:

    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.

    Mirrors are a central part of Scala Reflection. All information provided by reflection is made accessible through Mirrors. 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" Mirrors (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 Mirrors make use of only classloader Mirrors to load Symbols by name.

    The entry point to classloader Mirrors is via scala.reflect.macros.blackbox.Context#mirror or scala.reflect.macros.whitebox.Context#mirror. Typical methods which use classloader Mirrors 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 Strings to lookup the Symbol.

    Runtime Mirrors

    Runtime Mirrors make use of both classloader and invoker Mirrors.

    The entry point to Mirrors 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 Mirrors interact are available below.

    Types of Mirrors, Their Use Cases & Examples

    scala.reflect.api.Mirrors#ReflectiveMirror. Used for loading Symbols 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 Mirrors 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 Mirrorss, see the Reflection Guide: Mirrors

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

scala.reflect.api.Mirrors

MethodMirror

trait MethodMirror extends AnyRef

A mirror that reflects a method. See the overview page for details on how to use runtime reflection.

Source
Mirrors.scala
Linear Supertypes
AnyRef, Any
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Inherited
  1. MethodMirror
  2. AnyRef
  3. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. All

Abstract Value Members

  1. abstract def apply(args: Any*): Any

    The result of applying the method to the given arguments

    The result of applying the method to the given arguments

    Scala reflection uses reflection capabilities of the underlying platform, so FieldMirror.get might throw platform-specific exceptions associated with invoking the corresponding method or constructor.

  2. abstract def bind(newReceiver: Any): Universe.MethodMirror

    Creates a new mirror which uses the same symbol, but is bound to a different receiver.

    Creates a new mirror which uses the same symbol, but is bound to a different receiver. This is significantly faster than recreating the mirror from scratch.

  3. abstract def receiver: Any

    The receiver object of the method

  4. abstract def symbol: Universe.MethodSymbol

    The method symbol representing the method

Concrete Value Members

  1. 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
  2. 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
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from Universe.MethodMirror to any2stringadd[Universe.MethodMirror] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (Universe.MethodMirror, B)
    Implicit
    This member is added by an implicit conversion from Universe.MethodMirror to ArrowAssoc[Universe.MethodMirror] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. 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
  6. 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.

  7. 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

  8. def ensuring(cond: (Universe.MethodMirror) ⇒ Boolean, msg: ⇒ Any): Universe.MethodMirror
    Implicit
    This member is added by an implicit conversion from Universe.MethodMirror to Ensuring[Universe.MethodMirror] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  9. def ensuring(cond: (Universe.MethodMirror) ⇒ Boolean): Universe.MethodMirror
    Implicit
    This member is added by an implicit conversion from Universe.MethodMirror to Ensuring[Universe.MethodMirror] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  10. def ensuring(cond: Boolean, msg: ⇒ Any): Universe.MethodMirror
    Implicit
    This member is added by an implicit conversion from Universe.MethodMirror to Ensuring[Universe.MethodMirror] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def ensuring(cond: Boolean): Universe.MethodMirror
    Implicit
    This member is added by an implicit conversion from Universe.MethodMirror to Ensuring[Universe.MethodMirror] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  12. 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
  13. 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
  14. 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

  15. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from Universe.MethodMirror to StringFormat[Universe.MethodMirror] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  16. 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
  17. 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
  18. 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
  19. 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
  20. 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

  21. 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

  22. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  23. 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
  24. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  25. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  26. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  27. def →[B](y: B): (Universe.MethodMirror, B)
    Implicit
    This member is added by an implicit conversion from Universe.MethodMirror to ArrowAssoc[Universe.MethodMirror] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from Universe.MethodMirror to any2stringadd[Universe.MethodMirror]

Inherited by implicit conversion StringFormat from Universe.MethodMirror to StringFormat[Universe.MethodMirror]

Inherited by implicit conversion Ensuring from Universe.MethodMirror to Ensuring[Universe.MethodMirror]

Inherited by implicit conversion ArrowAssoc from Universe.MethodMirror to ArrowAssoc[Universe.MethodMirror]

Ungrouped