akka.japi
Class JavaPartialFunction<A,B>
java.lang.Object
scala.runtime.AbstractPartialFunction<A,B>
akka.japi.JavaPartialFunction<A,B>
- All Implemented Interfaces:
- scala.Function1<A,B>, scala.PartialFunction<A,B>
public abstract class JavaPartialFunction<A,B>
- extends scala.runtime.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 PurePartialFunction.apply(x, true)
and if that
does not throw noMatch()
it will continue with calling
PurePartialFunction.apply(x, false)
.
Nested classes/interfaces inherited from interface scala.PartialFunction |
scala.PartialFunction.AndThen<A,B,C>, scala.PartialFunction.Lifted<A,B>, scala.PartialFunction.OrElse<A,B>, scala.PartialFunction.Unlifted<A,B> |
Methods inherited from class scala.runtime.AbstractPartialFunction |
andThen, apply$mcDD$sp, apply$mcDF$sp, apply$mcDI$sp, apply$mcDJ$sp, apply$mcFD$sp, apply$mcFF$sp, apply$mcFI$sp, apply$mcFJ$sp, apply$mcID$sp, apply$mcIF$sp, apply$mcII$sp, apply$mcIJ$sp, apply$mcJD$sp, apply$mcJF$sp, apply$mcJI$sp, apply$mcJJ$sp, apply$mcVD$sp, apply$mcVF$sp, apply$mcVI$sp, apply$mcVJ$sp, apply$mcZD$sp, apply$mcZF$sp, apply$mcZI$sp, apply$mcZJ$sp, compose, lift, orElse, runWith, toString |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
JavaPartialFunction
public JavaPartialFunction()
noMatch
public static final java.lang.RuntimeException noMatch()
apply
public abstract B apply(A x,
boolean isCheck)
isDefinedAt
public final boolean isDefinedAt(A x)
apply
public final B apply(A x)
- Specified by:
apply
in interface scala.Function1<A,B>
- Overrides:
apply
in class scala.runtime.AbstractPartialFunction<A,B>
applyOrElse
public final <A1 extends A,B1> B1 applyOrElse(A1 x,
scala.Function1<A1,B1> default_)
- Specified by:
applyOrElse
in interface scala.PartialFunction<A,B>
- Overrides:
applyOrElse
in class scala.runtime.AbstractPartialFunction<A,B>