Vavr 0.10.6 · io.vavr.Function0 · APIdia, the JavaDoc alternative

Modifier and Type	Field and Description
public static final long	serialVersionUID The serial version uid.

Method Summary

Modifier and Type	Method and Description
public default < return type of after V> Function0<V>	Returns: a function composed of this and after andThen(Function<? super R, ? extends V> the function applied after this after) Returns a composed function that first applies this Function0 to the given argument and then applies Function `after` to the result.
public R	Returns: the result of function application apply() Applies this function to no arguments and returns the result.
public default int	Returns: an int value >= 0 arity() Returns the number of function arguments.
public static < the result type R> Function0<R>	Returns: a function always returning the given value constant(R the value to be returned value) Returns a function that always returns the constant value that you give in parameter.
public default Function0<R>	Returns: a curried function equivalent to this. curried() Returns a curried version of this function.
public default R	Returns: the result of `apply()` get() Implements java.util.function.Supplier.get. Implementation of java.util.function.Supplier#get(), just calls apply().
public default boolean	Returns: true, if this function is memoizing, false otherwise isMemoized() Checks if this function is memoizing (= caching) computed values.
public static < return type R> Function0<Option<R>>	Returns: a function that applies arguments to the given `partialFunction` and returns `Some(result)` if the function is defined for the given arguments, and `None` otherwise. lift(Supplier<? extends R> a function that is not defined for all values of the domain (e.g. by throwing) partialFunction) Lifts the given `partialFunction` into a total function that returns an `Option` result.
public static < return type R> Function0<Try<R>>	Returns: a function that applies arguments to the given `partialFunction` and returns `Success(result)` if the function is defined for the given arguments, and `Failure(throwable)` otherwise. liftTry(Supplier<? extends R> a function that is not defined for all values of the domain (e.g. by throwing) partialFunction) Lifts the given `partialFunction` into a total function that returns an `Try` result.
public default Function0<R>	Returns: a memoizing function equivalent to this. memoized() Returns a memoizing version of this function, which computes the return value for given arguments only one time.
public static < return type R> Function0<R>	Returns: the given `f` instance as narrowed type `Function0<R>` narrow(Function0<? extends R> A `Function0` f) Narrows the given `Function0<?`
public static < return type R> Function0<R>	Returns: a `Function0` of(Function0<R> (typically) a method reference, e.g. `Type::method` methodReference) Creates a `Function0` based on method reference lambda expression
public default Function0<R>	Returns: a reversed function equivalent to this. reversed() Returns a reversed version of this function.
public default Function1<Tuple0, R>	Returns: a tupled function equivalent to this. tupled() Returns a tupled version of this function.

serialVersionUID	back to summary
public static final long serialVersionUID The serial version uid.

Method Detail

andThen back to summary

andThen	back to summary
public 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. Parameters <V> return type of after after:Function<? super R, ? extends V> the function applied after this Returns:Function0<V> a function composed of this and after Exceptions NullPointerException: if after is null

public 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.

Parameters

<V>: return type of after
after:Function<? super R, ? extends V>: the function applied after this

Returns:Function0<V>

a function composed of this and after

Exceptions

NullPointerException:: if after is null

apply	back to summary
public R apply() Applies this function to no arguments and returns the result. Returns:R the result of function application

apply

back to summary

public R apply()

Applies this function to no arguments and returns the result.

Returns:R: the result of function application

arity	back to summary
public default int arity() Returns the number of function arguments. Returns:int an int value >= 0 See Also Arity

arity

back to summary

public default int arity()

Returns the number of function arguments.

Returns:int: an int value >= 0
See Also: Arity

constant	back to summary
public static <R> Function0<R> constant(R value) Returns a function that always returns the constant value that you give in parameter. Parameters <R> the result type value:R the value to be returned Returns:Function0<R> a function always returning the given value

constant

back to summary

public static <R> Function0<R> constant(R value)

Returns a function that always returns the constant value that you give in parameter.

Parameters

<R>: the result type
value:R: the value to be returned

Returns:Function0<R>

a function always returning the given value

curried	back to summary
public default Function0<R> curried() Returns a curried version of this function. Returns:Function0<R> a curried function equivalent to this.

curried

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public default Function0<R> curried()

Returns a curried version of this function.

Returns:Function0<R>: a curried function equivalent to this.

get back to summary

get	back to summary
public default R get() Implements java.util.function.Supplier.get. Implementation of java.util.function.Supplier#get(), just calls apply(). Returns:R the result of `apply()` Annotations @Override

public default R get()

Implements java.util.function.Supplier.get.

Implementation of java.util.function.Supplier#get(), just calls apply().

Returns:R

the result of apply()

Annotations

@Override

isMemoized	back to summary
public default boolean isMemoized() Checks if this function is memoizing (= caching) computed values. Returns:boolean true, if this function is memoizing, false otherwise

isMemoized

back to summary

public default boolean isMemoized()

Checks if this function is memoizing (= caching) computed values.

Returns:boolean: true, if this function is memoizing, false otherwise

lift back to summary

lift	back to summary
public static <R> Function0<Option<R>> lift(Supplier<? extends R> partialFunction) Lifts the given `partialFunction` into a total function that returns an `Option` result. Parameters <R> return type partialFunction:Supplier<? extends R> a function that is not defined for all values of the domain (e.g. by throwing) Returns:Function0<Option<R>> a function that applies arguments to the given `partialFunction` and returns `Some(result)` if the function is defined for the given arguments, and `None` otherwise. Annotations @SuppressWarnings:RedundantTypeArguments

public static <R> Function0<Option<R>> lift(Supplier<? extends R> partialFunction)

Lifts the given partialFunction into a total function that returns an Option result.

Parameters

<R>: return type
partialFunction:Supplier<? extends R>: a function that is not defined for all values of the domain (e.g. by throwing)

Returns:Function0<Option<R>>

a function that applies arguments to the given partialFunction and returns Some(result) if the function is defined for the given arguments, and None otherwise.

Annotations

@SuppressWarnings:RedundantTypeArguments

liftTry back to summary

liftTry	back to summary
public static <R> Function0<Try<R>> liftTry(Supplier<? extends R> partialFunction) Lifts the given `partialFunction` into a total function that returns an `Try` result. Parameters <R> return type partialFunction:Supplier<? extends R> a function that is not defined for all values of the domain (e.g. by throwing) Returns:Function0<Try<R>> a function that applies arguments to the given `partialFunction` and returns `Success(result)` if the function is defined for the given arguments, and `Failure(throwable)` otherwise.

public static <R> Function0<Try<R>> liftTry(Supplier<? extends R> partialFunction)

Lifts the given partialFunction into a total function that returns an Try result.

Parameters

<R>: return type
partialFunction:Supplier<? extends R>: a function that is not defined for all values of the domain (e.g. by throwing)

Returns:Function0<Try<R>>

a function that applies arguments to the given partialFunction and returns Success(result) if the function is defined for the given arguments, and Failure(throwable) otherwise.

memoized back to summary

memoized	back to summary
public default Function0<R> memoized() Returns a memoizing version of this function, which computes the return value for given arguments only one time. On subsequent calls given the same arguments the memoized value is returned. Please note that memoizing functions do not permit `null` as single argument or return value. Returns:Function0<R> a memoizing function equivalent to this.

public default Function0<R> memoized()

Returns a memoizing version of this function, which computes the return value for given arguments only one time. On subsequent calls given the same arguments the memoized value is returned.

Please note that memoizing functions do not permit null as single argument or return value.

Returns:Function0<R>: a memoizing function equivalent to this.

narrow back to summary

narrow	back to summary
public static <R> Function0<R> narrow(Function0<? extends R> f) Narrows the given `Function0<? extends R>` to `Function0<R>` Parameters <R> return type f:Function0<? extends R> A `Function0` Returns:Function0<R> the given `f` instance as narrowed type `Function0<R>` Annotations @SuppressWarnings:unchecked

public static <R> Function0<R> narrow(Function0<? extends R> f)

Narrows the given Function0<? extends R> to Function0<R>

Parameters

<R>: return type
f:Function0<? extends R>: A Function0

Returns:Function0<R>

the given f instance as narrowed type Function0<R>

Annotations

@SuppressWarnings:unchecked

of back to summary

of	back to summary
public static <R> Function0<R> of(Function0<R> methodReference) Creates a `Function0` based on method reference lambda expression 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` Parameters <R> return type methodReference:Function0<R> (typically) a method reference, e.g. `Type::method` Returns:Function0<R> a `Function0`

public static <R> Function0<R> of(Function0<R> methodReference)

Creates a 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

Parameters

<R>: return type
methodReference:Function0<R>: (typically) a method reference, e.g. Type::method

Returns:Function0<R>

a Function0

reversed	back to summary
public default Function0<R> reversed() Returns a reversed version of this function. This may be useful in a recursive context. Returns:Function0<R> a reversed function equivalent to this.

reversed

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public default Function0<R> reversed()

Returns a reversed version of this function. This may be useful in a recursive context.

Returns:Function0<R>: a reversed function equivalent to this.

tupled	back to summary
public default Function1<Tuple0, R> tupled() Returns a tupled version of this function. Returns:Function1<Tuple0, R> a tupled function equivalent to this.

tupled

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public default Function1<Tuple0, R> tupled()

Returns a tupled version of this function.

Returns:Function1<Tuple0, R>: a tupled function equivalent to this.

public Interface Function0<R>

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