Packages

abstract class JavaPartialFunction[A, B] extends AbstractPartialFunction[A, B]

Helper for implementing a *pure* partial function: it will possibly be invoked multiple times for a single “application”, because its only abstract method is used for both isDefinedAt() and apply(); the former is mapped to isCheck == true and the latter to isCheck == false for those cases where this is important to know.

Failure to match is signaled by throwing noMatch(), i.e. not returning normally (the exception used in this case is pre-allocated, hence not that expensive).

new JavaPartialFunction<Object, String>() {
  public String apply(Object in, boolean isCheck) {
    if (in instanceof TheThing) {
      if (isCheck) return null; // to spare the expensive or side-effecting code
      return doSomethingWithTheThing((TheThing) in);
    } else {
      throw noMatch();
    }
  }
}

The typical use of partial functions from Akka looks like the following:

if (pf.isDefinedAt(x)) {
  pf.apply(x);
}

i.e. it will first call JavaPartialFunction.apply(x, true) and if that does not throw noMatch() it will continue with calling JavaPartialFunction.apply(x, false).

Source
JavaAPI.scala
Linear Supertypes
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Inherited
  1. JavaPartialFunction
  2. AbstractPartialFunction
  3. PartialFunction
  4. Function1
  5. AnyRef
  6. Any
Implicitly
  1. by UnliftOps
  2. by any2stringadd
  3. by StringFormat
  4. by Ensuring
  5. by ArrowAssoc
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Visibility
  1. Public
  2. Protected

Instance Constructors

  1. new JavaPartialFunction()

Abstract Value Members

  1. abstract def apply(x: A, isCheck: Boolean): B
    Annotations
    @throws(classOf[Exception])

Concrete Value Members

  1. def andThen[C](k: PartialFunction[B, C]): PartialFunction[A, C]
    Definition Classes
    PartialFunction
  2. def andThen[C](k: (B) => C): PartialFunction[A, C]
    Definition Classes
    PartialFunction → Function1
  3. final def apply(x: A): B
    Definition Classes
    JavaPartialFunction → AbstractPartialFunction → Function1
  4. final def applyOrElse[A1 <: A, B1 >: B](x: A1, default: (A1) => B1): B1
    Definition Classes
    JavaPartialFunction → PartialFunction
  5. def compose[R](k: PartialFunction[R, A]): PartialFunction[R, B]
    Definition Classes
    PartialFunction
  6. def compose[A](g: (A) => A): (A) => B
    Definition Classes
    Function1
    Annotations
    @unspecialized()
  7. def elementWise: ElementWiseExtractor[A, B]
    Definition Classes
    PartialFunction
  8. final def isDefinedAt(x: A): Boolean
    Definition Classes
    JavaPartialFunction → PartialFunction
  9. def lift: (A) => scala.Option[B]
    Definition Classes
    PartialFunction
  10. def orElse[A1 <: A, B1 >: B](that: PartialFunction[A1, B1]): PartialFunction[A1, B1]
    Definition Classes
    PartialFunction
  11. def runWith[U](action: (B) => U): (A) => Boolean
    Definition Classes
    PartialFunction
  12. def toString(): String
    Definition Classes
    Function1 → AnyRef → Any
  13. def unapply(a: A): scala.Option[B]
    Definition Classes
    PartialFunction
  14. def unlift: PartialFunction[A, B]
    Implicit
    This member is added by an implicit conversion from JavaPartialFunction[A, B] toUnliftOps[A, B] performed by method UnliftOps in scala.Function1.This conversion will take place only if B is a subclass of scala.Option[B] (B <: scala.Option[B]).
    Definition Classes
    UnliftOps