Package com.google.common.base

Interface Function<F,T>

All Known Subinterfaces:

LoadingCache<K,V>

All Known Implementing Classes:

AbstractLoadingCache, CacheLIRS, ForwardingLoadingCache, ForwardingLoadingCache.SimpleForwardingLoadingCache

@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)

Method Summary

Modifier and Type	Method	Description
T	apply(F input)	Returns the result of applying this function to input.
boolean	equals(java.lang.Object object)	Indicates whether another object is equal to this function.

Method Detail

apply

@Nullable
T apply(@Nullable
        F input)

Returns the result of applying this function to input. 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 that Objects.equal(function.apply(a), function.apply(b)).

Throws:

java.lang.NullPointerException - if input is null and this function does not accept null arguments

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 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.

Overrides:

equals in class java.lang.Object