Packages

final case class ProviderMagnet[+A](get: Provider) extends Product with Serializable

A function that receives its arguments from DI object graph, including named instances via izumi.distage.model.definition.Id annotation.

The following syntaxes are supported by extractor macro:

Inline lambda:

make[Unit].from {
  i: Int @Id("special") => ()
}

Method reference:

def constructor(@Id("special") i: Int): Unit = ()

make[Unit].from(constructor _)

make[Unit].from(constructor(_))

Function value with an annotated signature:

val constructor: (Int @Id("special"), String @Id("special")) => Unit = (_, _) => ()

make[Unit].from(constructor)

Annotation processing is done by a macro and macros are rarely perfect, Prefer passing an inline lambda such as { x => y } or a method reference such as (method _) or (method(_)) Annotation info may be lost ONLY in a few cases detailed below, though:

  • If an annotated method has been hidden by an intermediate val
  • If an .apply method of a case class is passed when case class _parameters_ are annotated, not their types

As such, prefer annotating parameter types, not parameters: class X(i: Int @Id("special")) { ... }

When binding a case class to constructor, prefer passing new X(_) instead of X.apply _ because apply will not preserve parameter annotations from case class definitions:

case class X(@Id("special") i: Int)

make[X].from(X.apply _) // summons regular Int
make[X].from(new X(_)) // summons special Int

HOWEVER, if you annotate the types of parameters instead of their names, apply WILL work:

case class X(i: Int @Id("special"))

make[X].from(X.apply _) // summons special Int

Using intermediate vals will lose annotations when converting a method into a function value, prefer using annotated method directly as method reference (method _):

def constructorMethod(@Id("special") i: Int): Unit = ()

val constructor = constructorMethod _

make[Unit].from(constructor) // Will summon regular Int, not a "special" Int from DI object graph

ProviderMagnet forms an applicative functor via its ProviderMagnet.pure & map2 methods

See also

izumi.distage.model.reflection.macros.ProviderMagnetMacro]

'Magnet' in the name refers to the Magnet Pattern: http://spray.io/blog/2012-12-13-the-magnet-pattern/

Linear Supertypes
Serializable, Product, Equals, AnyRef, Any
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Inherited
  1. ProviderMagnet
  2. Serializable
  3. Product
  4. Equals
  5. AnyRef
  6. Any
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Visibility
  1. Public
  2. Protected

Instance Constructors

  1. new ProviderMagnet(get: Provider)

Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##: Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. def addDependencies(keys: Seq[DIKey]): ProviderMagnet[A]
  5. def addDependency(key: DIKey): ProviderMagnet[A]
  6. def addDependency[B](implicit arg0: Tag[B]): ProviderMagnet[A]

    Add B as an unused dependency of this Provider

  7. def ap[B, C](that: ProviderMagnet[B])(implicit ev: <:<[A, (B) => C], tag: Tag[C]): ProviderMagnet[C]

    Apply a function produced by this Provider to the argument produced by that Provider

  8. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  9. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native()
  10. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  11. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable])
  12. def flatAp[B](that: ProviderMagnet[(A) => B])(implicit arg0: Tag[B]): ProviderMagnet[B]

    Applicative's ap method - can be used to chain transformations like flatMap.

    Applicative's ap method - can be used to chain transformations like flatMap. Apply a function produced by that Provider to the argument produced by this Provider

  13. val get: Provider
  14. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  15. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  16. def map[B](f: (A) => B)(implicit arg0: Tag[B]): ProviderMagnet[B]
  17. def map2[B, C](that: ProviderMagnet[B])(f: (A, B) => C)(implicit arg0: Tag[C]): ProviderMagnet[C]
  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. def productElementNames: Iterator[String]
    Definition Classes
    Product
  22. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  23. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  24. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  25. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()
  26. def zip[B](that: ProviderMagnet[B]): ProviderMagnet[(A, B)]

Inherited from Serializable

Inherited from Product

Inherited from Equals

Inherited from AnyRef

Inherited from Any

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