fj.control.parallel

Class Callables

java.lang.Object

fj.control.parallel.Callables

public final class Callables
extends java.lang.Object

Monadic functions and conversion methods for java.util.concurrent.Callable.

Method Summary

Modifier and Type	Method and Description
static <A,B> java.util.concurrent.Callable<B>	apply(java.util.concurrent.Callable<A> ca, java.util.concurrent.Callable<F<A,B>> cf) Performs function application within a callable (applicative functor pattern).
static <A,B> F<F<A,B>,F<A,java.util.concurrent.Callable<B>>>	arrow() Provides a transformation from a function to a Callable-valued function that is equivalent to it.
static <A,B,C> java.util.concurrent.Callable<C>	bind(java.util.concurrent.Callable<A> ca, java.util.concurrent.Callable<B> cb, F<A,F<B,C>> f) Binds the given function to the values in the given callables with a final join.
static <A,B> java.util.concurrent.Callable<B>	bind(java.util.concurrent.Callable<A> a, F<A,java.util.concurrent.Callable<B>> f) Binds the given function to the value in a Callable with a final join.
static <A> F<A,java.util.concurrent.Callable<A>>	callable() Provides a transformation from a value to a Callable that completely preserves that value.
static <A> java.util.concurrent.Callable<A>	callable(A a) Returns a callable that completely preserves the argument.
static <A> java.util.concurrent.Callable<A>	callable(java.lang.Exception e) Returns a callable that throws the given exception.
static <A,B> F<A,java.util.concurrent.Callable<B>>	callable(F<A,B> f) Wraps a given function's return value in a Callable.
static <A> F<java.util.concurrent.Callable<A>,P1<Either<java.lang.Exception,A>>>	either() Returns a transformation from a Callable to an Either.
static <A> P1<Either<java.lang.Exception,A>>	either(java.util.concurrent.Callable<A> a) Turns the given Callable into either an exception or the value in the Callable.
static <A,B> F<java.util.concurrent.Callable<A>,java.util.concurrent.Callable<B>>	fmap(F<A,B> f) Lifts any function to a function on Callables.
static <A> F<P1<Either<java.lang.Exception,A>>,java.util.concurrent.Callable<A>>	fromEither() Returns a transformation from an Either to a Callable.
static <A> java.util.concurrent.Callable<A>	fromEither(F0<Either<java.lang.Exception,A>> e) Turns a given Either value into the equivalent Callable.
static <A> F<P1<Option<A>>,java.util.concurrent.Callable<A>>	fromOption() Returns a transformation from an optional value to a Callable
static <A> java.util.concurrent.Callable<A>	fromOption(F0<Option<A>> o) Turns an optional value into a Callable.
static <A> java.util.concurrent.Callable<A>	join(java.util.concurrent.Callable<java.util.concurrent.Callable<A>> a) Joins a Callable of a Callable with a bind operation.
static <A,B,C> F<java.util.concurrent.Callable<A>,F<java.util.concurrent.Callable<B>,java.util.concurrent.Callable<C>>>	liftM2(F<A,F<B,C>> f) Promotes a function of arity-2 to a function on callables.
static <A> F<java.util.concurrent.Callable<A>,java.util.concurrent.Callable<A>>	normalise() A first-class version of the normalise function.
static <A> java.util.concurrent.Callable<A>	normalise(java.util.concurrent.Callable<A> a) Normalises the given Callable by calling it and wrapping the result in a new Callable.
static <A> F<java.util.concurrent.Callable<A>,P1<Option<A>>>	option() Returns a transformation from a Callable to an optional value.
static <A> P1<Option<A>>	option(java.util.concurrent.Callable<A> a) Turns the given Callable into an optional value.
static <A> F<List<java.util.concurrent.Callable<A>>,java.util.concurrent.Callable<List<A>>>	sequence_() A first-class version of the sequence method.
static <A> java.util.concurrent.Callable<List<A>>	sequence(List<java.util.concurrent.Callable<A>> as) Turns a List of Callables into a single Callable of a List.

Methods inherited from class java.lang.Object

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

Method Detail

callable

public static <A> java.util.concurrent.Callable<A> callable(A a)

Returns a callable that completely preserves the argument. The unit function for Callables.

Parameters:

a - A value to preserve in a Callable

Returns:

A Callable that yields the argument when called.

callable

public static <A> java.util.concurrent.Callable<A> callable(java.lang.Exception e)

Returns a callable that throws the given exception. The unit function for Callables.

Parameters:

e - The exception to throw when the Callable is called.

Returns:

A callable that always throws the given exception.

callable

public static <A> F<A,java.util.concurrent.Callable<A>> callable()

Provides a transformation from a value to a Callable that completely preserves that value.

Returns:

A function from a value to a Callable that completely preserves that value.

callable

public static <A,B> F<A,java.util.concurrent.Callable<B>> callable(F<A,B> f)

Wraps a given function's return value in a Callable. The Kleisli arrow for Callables.

Parameters:

f - The function whose return value to wrap in a Callable.

Returns:

The equivalent function whose return value is wrapped in a Callable.

arrow

public static <A,B> F<F<A,B>,F<A,java.util.concurrent.Callable<B>>> arrow()

Provides a transformation from a function to a Callable-valued function that is equivalent to it. The first-class Kleisli arrow for Callables.

Returns:

A transformation from a function to the equivalent Callable-valued function.

bind

public static <A,B> java.util.concurrent.Callable<B> bind(java.util.concurrent.Callable<A> a,
                                                          F<A,java.util.concurrent.Callable<B>> f)

Binds the given function to the value in a Callable with a final join.

Parameters:

a - A value in a Callable to which to apply a function.

f - A function to apply to the value in a Callable.

Returns:

The result of applying the function in the second argument to the value of the Callable in the first.

fmap

public static <A,B> F<java.util.concurrent.Callable<A>,java.util.concurrent.Callable<B>> fmap(F<A,B> f)

Lifts any function to a function on Callables.

Parameters:

f - A function to lift to a function on Callables.

Returns:

That function lifted to a function on Callables.

apply

public static <A,B> java.util.concurrent.Callable<B> apply(java.util.concurrent.Callable<A> ca,
                                                           java.util.concurrent.Callable<F<A,B>> cf)

Performs function application within a callable (applicative functor pattern).

Parameters:

ca - The callable to which to apply a function.

cf - The callable function to apply.

Returns:

A new callable after applying the given callable function to the first argument.

bind

public static <A,B,C> java.util.concurrent.Callable<C> bind(java.util.concurrent.Callable<A> ca,
                                                            java.util.concurrent.Callable<B> cb,
                                                            F<A,F<B,C>> f)

Binds the given function to the values in the given callables with a final join.

Parameters:

ca - A given callable to bind the given function with.

cb - A given callable to bind the given function with.

f - The function to apply to the values in the given callables.

Returns:

A new callable after performing the map, then final join.

join

public static <A> java.util.concurrent.Callable<A> join(java.util.concurrent.Callable<java.util.concurrent.Callable<A>> a)

Joins a Callable of a Callable with a bind operation.

Parameters:

a - The Callable of a Callable to join.

Returns:

A new Callable that is the join of the given Callable.

liftM2

public static <A,B,C> F<java.util.concurrent.Callable<A>,F<java.util.concurrent.Callable<B>,java.util.concurrent.Callable<C>>> liftM2(F<A,F<B,C>> f)

Promotes a function of arity-2 to a function on callables.

Parameters:

f - The function to promote.

Returns:

A function of arity-2 promoted to map over callables.

sequence

public static <A> java.util.concurrent.Callable<List<A>> sequence(List<java.util.concurrent.Callable<A>> as)

Turns a List of Callables into a single Callable of a List.

Parameters:

as - The list of callables to transform.

Returns:

A single callable for the given List.

sequence_

public static <A> F<List<java.util.concurrent.Callable<A>>,java.util.concurrent.Callable<List<A>>> sequence_()

A first-class version of the sequence method.

Returns:

A function from a List of Callables to a single Callable of a List.

option

public static <A> P1<Option<A>> option(java.util.concurrent.Callable<A> a)

Turns the given Callable into an optional value.

Parameters:

a - The callable to convert to an optional value.

Returns:

An optional value that yields the value in the Callable, or None if the Callable fails.

option

public static <A> F<java.util.concurrent.Callable<A>,P1<Option<A>>> option()

Returns a transformation from a Callable to an optional value.

Returns:

a function that turns a Callable into an optional value.

either

public static <A> P1<Either<java.lang.Exception,A>> either(java.util.concurrent.Callable<A> a)

Turns the given Callable into either an exception or the value in the Callable.

Parameters:

a - The callable to convert to an Either value.

Returns:

Either the value in the given Callable, or the Exception with which the Callable fails.

either

public static <A> F<java.util.concurrent.Callable<A>,P1<Either<java.lang.Exception,A>>> either()

Returns a transformation from a Callable to an Either.

Returns:

a function that turns a Callable into an Either.

fromEither

public static <A> java.util.concurrent.Callable<A> fromEither(F0<Either<java.lang.Exception,A>> e)

Turns a given Either value into the equivalent Callable.

Parameters:

e - Either an exception or a value to wrap in a Callable

Returns:

A Callable equivalent to the given Either value.

fromEither

public static <A> F<P1<Either<java.lang.Exception,A>>,java.util.concurrent.Callable<A>> fromEither()

Returns a transformation from an Either to a Callable.

Returns:

a function that turns an Either into a Callable.

fromOption

public static <A> java.util.concurrent.Callable<A> fromOption(F0<Option<A>> o)

Turns an optional value into a Callable.

Parameters:

o - An optional value to turn into a Callable.

Returns:

A Callable that yields some value or throws an exception in the case of no value.

fromOption

public static <A> F<P1<Option<A>>,java.util.concurrent.Callable<A>> fromOption()

Returns a transformation from an optional value to a Callable

Returns:

A function that turns an optional value into a Callable that yields some value or throws an exception in the case of no value.

normalise

public static <A> java.util.concurrent.Callable<A> normalise(java.util.concurrent.Callable<A> a)

Normalises the given Callable by calling it and wrapping the result in a new Callable. If the given Callable throws an Exception, the resulting Callable will throw that same Exception.

Parameters:

a - The callable to evaluate.

Returns:

A normalised callable that just returns the result of calling the given callable.

normalise

public static <A> F<java.util.concurrent.Callable<A>,java.util.concurrent.Callable<A>> normalise()

A first-class version of the normalise function.

Returns:

A function that normalises the given Callable by calling it and wrapping the result in a new Callable.