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
AbstractPartialFunction[A, B], PartialFunction[A, B], (A) ⇒ B, AnyRef, Any
Ordering
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  2. By Inheritance
Inherited
  1. JavaPartialFunction
  2. AbstractPartialFunction
  3. PartialFunction
  4. Function1
  5. AnyRef
  6. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. All

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: (B) ⇒ C): PartialFunction[A, C]
    Definition Classes
    PartialFunction → Function1
  2. final def apply(x: A): B
    Definition Classes
    JavaPartialFunction → AbstractPartialFunction → Function1
  3. final def applyOrElse[A1 <: A, B1 >: B](x: A1, default: (A1) ⇒ B1): B1
    Definition Classes
    JavaPartialFunction → PartialFunction
  4. def compose[A](g: (A) ⇒ A): (A) ⇒ B
    Definition Classes
    Function1
    Annotations
    @unspecialized()
  5. final def isDefinedAt(x: A): Boolean
    Definition Classes
    JavaPartialFunction → PartialFunction
  6. def lift: (A) ⇒ scala.Option[B]
    Definition Classes
    PartialFunction
  7. def orElse[A1 <: A, B1 >: B](that: PartialFunction[A1, B1]): PartialFunction[A1, B1]
    Definition Classes
    PartialFunction
  8. def runWith[U](action: (B) ⇒ U): (A) ⇒ Boolean
    Definition Classes
    PartialFunction
  9. def toString(): String
    Definition Classes
    Function1 → AnyRef → Any