japi

Type Members

1. trait Creator[T] extends Serializable

   

   A constructor/factory, takes no parameters but creates a new value of type T every call.

   A constructor/factory, takes no parameters but creates a new value of type T every call.

   Annotations

   @SerialVersionUID()

2. trait Effect extends AnyRef

   

   An executable piece of code that takes no parameters and doesn't return any value.

3. trait Function[T, R] extends AnyRef

   

   A Function interface.

   A Function interface. Used to create first-class-functions is Java.

4. trait Function2[T1, T2, R] extends AnyRef

   

   A Function interface.

   A Function interface. Used to create 2-arg first-class-functions is Java.

5. class JAPI extends AnyRef

   

6. 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.

   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).

7. sealed abstract class Option[A] extends Iterable[A]

   

   This class represents optional values.

   This class represents optional values. Instances of Option are either instances of case class Some or it is case object None.

8. case class Pair[A, B](first: A, second: B) extends Product with Serializable

   

   Java API: Represents a tuple of two elements.

   Java API: Represents a tuple of two elements.

   Annotations

   @SerialVersionUID()

9. trait Predicate[T] extends AnyRef

   

   Java API: Defines a criteria and determines whether the parameter meets this criteria.

10. trait Procedure[T] extends AnyRef

    

    A Procedure is like a Function, but it doesn't produce a return value.