@GwtCompatible public interface Function<F,T>
Functions class provides common functions and related utilities.
See the Guava User Guide article on the use of
This interface is now a legacy type. Use
java.util.function.Function (or the
appropriate primitive specialization such as
ToIntFunction) instead whenever possible.
Otherwise, at least reduce explicit dependencies on this type by using lambda expressions
or method references instead of classes, leaving your code easier to migrate in the future.
To use an existing function (say, named
function) in a context where the other
type of function is expected, use the method reference
function::apply. A future
com.google.common.base.Function will be made to extend
java.util.function.Function, making conversion code necessary only in one direction. At that
time, this interface will be officially discouraged.
@CanIgnoreReturnValue @NullableDecl T apply(@NullableDecl F input)
input. This method is generally expected, but not absolutely required, to have the following properties:
(a, b)implies that
inputis null and this function does not accept null arguments
boolean equals(@NullableDecl Object object)
Functionthat behaves identically to this function.
Warning: do not depend on the behavior of this method.
Function instances in this library have implemented this method to
recognize certain cases where distinct
Function instances would in fact behave
identically. However, as code migrates to
java.util.function, that behavior will
disappear. It is best not to depend on it.
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