@GwtCompatible public interface Function<F,T>
The Functions
class provides common functions and related utilites.
See the Guava User Guide article on the use of Function
.
@Nullable T apply(@Nullable F input)
input
. This method is generally
expected, but not absolutely required, to have the following properties:
Objects.equal
(a, b)
implies that Objects.equal(function.apply(a),
function.apply(b))
.
NullPointerException
- if input
is null and this function does not accept null
argumentsboolean equals(@Nullable Object object)
Most implementations will have no reason to override the behavior of Object.equals(java.lang.Object)
.
However, an implementation may also choose to return true
whenever object
is a
Function
that it considers interchangeable with this one. "Interchangeable"
typically means that Objects.equal(this.apply(f), that.apply(f))
is true for all
f
of type F
. Note that a false
result from this method does not imply
that the functions are known not to be interchangeable.
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