com.atlassian.util.concurrent
Class Functions

java.lang.Object
  com.atlassian.util.concurrent.Functions

public final class Functions
extends java.lang.Object

Method Summary

static <D,R> Function<D,R>	fromSupplier(Supplier<R> supplier) Get a function that uses the Supplier as a factory for all inputs.
static <T> Function<T,T>	identity() Get a function that always returns the input.
static <T,R> com.google.common.base.Function<T,R>	toGoogleFunction(Function<T,R> function) Map to a google-collections Function.
static <T,R> Function<T,R>	weakMemoize(Function<T,R> f) Get a function that weakly memoizes the output – ie.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

fromSupplier

public static <D,R> Function<D,R> fromSupplier(@NotNull
                                               Supplier<R> supplier)

Get a function that uses the Supplier as a factory for all inputs.

Type Parameters:

D - the key type, ignored

R - the result type

Parameters:

supplier - called for all inputs

Returns:

the function

identity

public static <T> Function<T,T> identity()

Get a function that always returns the input.

Type Parameters:

T - the type of the input and the output for the function.

Returns:

the identity function.

weakMemoize

public static <T,R> Function<T,R> weakMemoize(Function<T,R> f)

Get a function that weakly memoizes the output – ie. subsequent calls for the same input value will return the same reference if it has not been garbage collected because there are no external strong referrents to it.

Type Parameters:

T - the input or key type for the function. Must be a value (immutable) and have a well behaved hashcode implementation.

R - the output type of the for the function.

Parameters:

f - the function to call if the value is not already cached.

Returns:

the function that will .

toGoogleFunction

public static <T,R> com.google.common.base.Function<T,R> toGoogleFunction(Function<T,R> function)

Map to a google-collections Function.

Type Parameters:

T - input type

R - output type

Parameters:

function - the function to map

Returns:

the mapped function.