Function1 (Javaslang 2.0.1 API)

Type Parameters:

T1 - argument 1 of the function

R - return type of the function

All Superinterfaces:

Function<T1,R>, Serializable, λ<R>

All Known Subinterfaces:

IndexedSeq<T>, LinearSeq<T>, List<T>, Map<K,V>, Seq<T>, Set<T>, SortedMap<K,V>, SortedSet<T>, Stream<T>

All Known Implementing Classes:

Array, CharSeq, HashMap, HashSet, LinkedHashMap, LinkedHashSet, List.Cons, List.Nil, Queue, Stream.Cons, Stream.Empty, TreeMap, TreeSet, Vector

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
```
@FunctionalInterface
public interface Function1<T1,R>
extends λ<R>, Function<T1,R>
```
Represents a function with one argument.

Since:

1.1.0

Author:

Daniel Dietrich

Nested Class Summary
- Nested classes/interfaces inherited from interface javaslang.λ
  λ.Memoized

Field Summary

Fields
Modifier and Type Field and Description

static long serialVersionUID
The serial version uid.

Fields
Modifier and Type	Field and Description
`static long`	`serialVersionUID` The serial version uid.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`default <V> Function1<T1,V>`	`andThen(Function<? super R,? extends V> after)` Returns a composed function that first applies this Function1 to the given argument and then applies Function `after` to the result.
`R`	`apply(T1 t1)` Applies this function to one argument and returns the result.
`default int`	`arity()`
`default <V> Function1<V,R>`	`compose(Function<? super V,? extends T1> before)` Returns a composed function that first applies the Function `before` the given argument and then applies this Function1 to the result.
`default Function1<T1,R>`	`curried()` Returns a curried version of this function.
`static <T> Function1<T,T>`	`identity()` Returns the identity Function1, i.e.
`static <T1,R> Function1<T1,Option<R>>`	`lift(Function1<T1,R> partialFunction)` Lifts the given `partialFunction` into a total function that returns an `Option` result.
`default Function1<T1,R>`	`memoized()` Returns a memoizing version of this function, which computes the return value for given arguments only one time.
`static <T1,R> Function1<T1,R>`	`of(Function1<T1,R> methodReference)` Creates a `Function1` based on method reference lambda expression Examples (w.l.o.g.
`default Function1<T1,R>`	`reversed()` Returns a reversed version of this function.
`default Function1<Tuple1<T1>,R>`	`tupled()` Returns a tupled version of this function.

Methods inherited from interface javaslang.λ
isMemoized

- Field Detail
  - serialVersionUID
```
static final long serialVersionUID
```
    The serial version uid.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - of
```
static <T1,R> Function1<T1,R> of(Function1<T1,R> methodReference)
```
    Creates a Function1 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
 
```
    Type Parameters:
    
    R - return type
    
    T1 - 1st argument
    
    Parameters:
    
    methodReference - (typically) a method reference, e.g. Type::method
    
    Returns:
    
    a Function1
  - lift
```
static <T1,R> Function1<T1,Option<R>> lift(Function1<T1,R> partialFunction)
```
    Lifts the given partialFunction into a total function that returns an Option result.
    
    Type Parameters:
    
    R - return type
    
    T1 - 1st argument
    
    Parameters:
    
    partialFunction - a function that is not defined for all values of the domain (e.g. by throwing)
    
    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.
  - identity
```
static <T> Function1<T,T> identity()
```
    Returns the identity Function1, i.e. the function that returns its input.
    
    Specified by:
    
    identity in interface Function<T1,R>
    
    Type Parameters:
    
    T - argument type (and return type) of the identity function
    
    Returns:
    
    the identity Function1
  - apply
```
R apply(T1 t1)
```
    Applies this function to one argument and returns the result.
    
    Specified by:
    
    apply in interface Function<T1,R>
    
    Parameters:
    
    t1 - argument 1
    
    Returns:
    
    the result of function application
  - arity
```
default int arity()
```
    Specified by:
    
    arity in interface λ<R>
    
    Returns:
    
    the number of function arguments.
    
    See Also:
    
    Arity
  - curried
```
default Function1<T1,R> curried()
```
    Description copied from interface: λ
    
    Returns a curried version of this function.
    
    Specified by:
    
    curried in interface λ<R>
    
    Returns:
    
    a curried function equivalent to this.
  - tupled
```
default Function1<Tuple1<T1>,R> tupled()
```
    Description copied from interface: λ
    
    Returns a tupled version of this function.
    
    Specified by:
    
    tupled in interface λ<R>
    
    Returns:
    
    a tupled function equivalent to this.
  - reversed
```
default Function1<T1,R> reversed()
```
    Description copied from interface: λ
    
    Returns a reversed version of this function. This may be useful in a recursive context.
    
    Specified by:
    
    reversed in interface λ<R>
    
    Returns:
    
    a reversed function equivalent to this.
  - memoized
```
default Function1<T1,R> memoized()
```
    Description copied from interface: λ
    
    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.
    
    Specified by:
    
    memoized in interface λ<R>
    
    Returns:
    
    a memoizing function equivalent to this.
  - andThen
```
default <V> Function1<T1,V> andThen(Function<? super R,? extends V> after)
```
    Returns a composed function that first applies this Function1 to the given argument and then applies Function after to the result.
    
    Specified by:
    
    andThen in interface Function<T1,R>
    
    Type Parameters:
    
    V - return type of after
    
    Parameters:
    
    after - the function applied after this
    
    Returns:
    
    a function composed of this and after
    
    Throws:
    
    NullPointerException - if after is null
  - compose
```
default <V> Function1<V,R> compose(Function<? super V,? extends T1> before)
```
    Returns a composed function that first applies the Function before the given argument and then applies this Function1 to the result.
    
    Specified by:
    
    compose in interface Function<T1,R>
    
    Type Parameters:
    
    V - argument type of before
    
    Parameters:
    
    before - the function applied before this
    
    Returns:
    
    a function composed of before and this
    
    Throws:
    
    NullPointerException - if before is null

Interface Function1<T1,R>

Nested Class Summary

Nested classes/interfaces inherited from interface javaslang.λ

Field Summary

Method Summary

Methods inherited from interface javaslang.λ

Field Detail

serialVersionUID

Method Detail

of

lift

identity

apply

arity

curried

tupled

reversed

memoized

andThen

compose