Package com.google.common.base
Interface Function<F,T>
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- All Known Implementing Classes:
Converter
@GwtCompatible public interface Function<F,T>
Determines an output value based on an input value.The
Functions
class provides common functions and related utilites.See the Guava User Guide article on the use of
Function
.- Since:
- 2.0 (imported from Google Collections Library)
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description T
apply(F input)
Returns the result of applying this function toinput
.boolean
equals(java.lang.Object object)
Indicates whether another object is equal to this function.
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Method Detail
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apply
@Nullable T apply(@Nullable F input)
Returns the result of applying this function toinput
. This method is generally expected, but not absolutely required, to have the following properties:- Its execution does not cause any observable side effects.
- The computation is consistent with equals; that is,
Objects.equal
(a, b)
implies thatObjects.equal(function.apply(a), function.apply(b))
.
- Throws:
java.lang.NullPointerException
- ifinput
is null and this function does not accept null arguments
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equals
boolean equals(@Nullable java.lang.Object object)
Indicates whether another object is equal to this function.Most implementations will have no reason to override the behavior of
Object.equals(java.lang.Object)
. However, an implementation may also choose to returntrue
wheneverobject
is aFunction
that it considers interchangeable with this one. "Interchangeable" typically means thatObjects.equal(this.apply(f), that.apply(f))
is true for allf
of typeF
. Note that afalse
result from this method does not imply that the functions are known not to be interchangeable.- Overrides:
equals
in classjava.lang.Object
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