T
- the type of the input to the functionR
- the type of the result of the function@FunctionalInterface public interface Function<T,R>
Represents a function that accepts one argument and produces a result.
This is a functional interface whose functional method is apply(Object)
.
R apply(T t)
Applies this function to the given argument.
t
- the function argumentdefault <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.
V
- the type of input to the before
function, and to the composed functionbefore
- the function to apply before this function is appliedbefore
function and then applies this functionNullPointerException
- if before is nullandThen(Function)
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.
V
- the type of output of the after
function, and of the composed functionafter
- the function to apply after this function is appliedafter
functionNullPointerException
- if after is nullcompose(Function)
static <T> Function<T,T> identity()
Returns a function that always returns its input argument.
T
- the type of the input and output objects to the function
© 1993–2017, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.