R - return type of the function@FunctionalInterface public interface Function0<R> extends λ<R>, Supplier<R>
λ.Memoized| Modifier and Type | Field and Description |
|---|---|
static long |
serialVersionUID
The serial version uid.
|
| Modifier and Type | Method and Description |
|---|---|
default <V> Function0<V> |
andThen(Function<? super R,? extends V> after)
Returns a composed function that first applies this Function0 to the given argument and then applies
Function
after to the result. |
R |
apply()
Applies this function to no arguments and returns the result.
|
default int |
arity() |
default Function0<R> |
curried()
Returns a curried version of this function.
|
default R |
get()
Implementation of Supplier.get(), just calls apply().
|
static <R> Function0<Option<R>> |
lift(Function0<R> partialFunction)
Lifts the given
partialFunction into a total function that returns an Option result. |
default Function0<R> |
memoized()
Returns a memoizing version of this function, which computes the return value for given arguments only one time.
|
static <R> Function0<R> |
of(Function0<R> methodReference)
|
default Function0<R> |
reversed()
Returns a reversed version of this function.
|
default Function1<Tuple0,R> |
tupled()
Returns a tupled version of this function.
|
isMemoizedstatic final long serialVersionUID
static <R> Function0<R> of(Function0<R> methodReference)
Function0 based on
Examples (w.l.o.g. referring to Function1):
// using a lambda expression
Function1<Integer, Integer> add1 = Function1.of(i -> i + 1);
// using a method reference (, e.g. Integer method(Integer i) { return i + 1; })
Function1<Integer, Integer> add2 = Function1.of(this::method);
// using a lambda reference
Function1<Integer, Integer> add3 = Function1.of(add1::apply);
Caution: Reflection loses type information of lambda references.
// type of a lambda expression
Type<?, ?> type1 = add1.getType(); // (Integer) -> Integer
// type of a method reference
Type<?, ?> type2 = add2.getType(); // (Integer) -> Integer
// type of a lambda reference
Type<?, ?> type3 = add3.getType(); // (Object) -> Object
R - return typemethodReference - (typically) a method reference, e.g. Type::methodFunction0static <R> Function0<Option<R>> lift(Function0<R> partialFunction)
partialFunction into a total function that returns an Option result.R - return typepartialFunction - a function that is not defined for all values of the domain (e.g. by throwing)partialFunction and returns Some(result)
if the function is defined for the given arguments, and None otherwise.R apply()
default R get()
default int arity()
default Function0<R> curried()
λdefault Function1<Tuple0,R> tupled()
λdefault Function0<R> reversed()
λdefault Function0<R> memoized()
λ
Please note that memoizing functions do not permit null as single argument or return value.
default <V> Function0<V> andThen(Function<? super R,? extends V> after)
after to the result.V - return type of afterafter - the function applied after thisNullPointerException - if after is nullCopyright © 2016. All Rights Reserved.