OpenJDK 27 · java.util.function.Function · APIdia, the JavaDoc alternative

Method Summary

Modifier and Type	Method and Description
public default < the type of output of the `after` function, and of the composed function V> Function<T, V>	Returns: a composed function that first applies this function and then applies the `after` function andThen(Function<? super R, ? extends V> the function to apply after this function is applied after) Returns a composed function that first applies this function to its input, and then applies the `after` function to the result.
public R	Returns: the function result apply(T the function argument t) Applies this function to the given argument.
public default < the type of input to the `before` function, and to the composed function V> Function<V, R>	Returns: a composed function that first applies the `before` function and then applies this function compose(Function<? super V, ? extends T> the function to apply before this function is applied before) Returns a composed function that first applies the `before` function to its input, and then applies this function to the result.
public static < the type of the input and output objects to the function T> Function<T, T>	Returns: a function that always returns its input argument identity() Returns a function that always returns its input argument.

Method Detail

andThen back to summary

andThen	back to summary
public default <V> Function<T, V> andThen(Function<? super R, ? extends V> after) Returns a composed function that first applies this function to its input, and then applies the `after` function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the composed function. Parameters <V> the type of output of the `after` function, and of the composed function after:Function<? super R, ? extends V> the function to apply after this function is applied Returns:Function<T, V> a composed function that first applies this function and then applies the `after` function Exceptions NullPointerException: if after is null See Also `compose(Function)`

public default <V> Function<T, V> andThen(Function<? super R, ? extends V> after)

Returns a composed function that first applies this function to its input, and then applies the after function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the composed function.

Parameters

<V>: the type of output of the after function, and of the composed function
after:Function<? super R, ? extends V>: the function to apply after this function is applied

Returns:Function<T, V>

a composed function that first applies this function and then applies the after function

Exceptions

NullPointerException:: if after is null

See Also

compose(Function)

apply	back to summary
public R apply(T t) Applies this function to the given argument. Parameters t:T the function argument Returns:R the function result

apply

back to summary

public R apply(T t)

Applies this function to the given argument.

Parameters

t:T: the function argument

Returns:R

the function result

compose back to summary

compose	back to summary
public default <V> Function<V, R> compose(Function<? super V, ? extends T> before) Returns a composed function that first applies the `before` function to its input, and then applies this function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the composed function. Parameters <V> the type of input to the `before` function, and to the composed function before:Function<? super V, ? extends T> the function to apply before this function is applied Returns:Function<V, R> a composed function that first applies the `before` function and then applies this function Exceptions NullPointerException: if before is null See Also `andThen(Function)`

public default <V> Function<V, R> compose(Function<? super V, ? extends T> before)

Returns a composed function that first applies the before function to its input, and then applies this function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the composed function.

Parameters

<V>: the type of input to the before function, and to the composed function
before:Function<? super V, ? extends T>: the function to apply before this function is applied

Returns:Function<V, R>

a composed function that first applies the before function and then applies this function

Exceptions

NullPointerException:: if before is null

See Also

andThen(Function)

identity	back to summary
public static <T> Function<T, T> identity() Returns a function that always returns its input argument. Parameters <T> the type of the input and output objects to the function Returns:Function<T, T> a function that always returns its input argument

identity

back to summary

public static <T> Function<T, T> identity()

Returns a function that always returns its input argument.

Parameters

<T>: the type of the input and output objects to the function

Returns:Function<T, T>

a function that always returns its input argument

public Interface Function<T, R>

Method Summary

Method Detail