cyclops

Class CompletableFutures.Instances

java.lang.Object

cyclops.CompletableFutures.Instances

Enclosing class:

CompletableFutures

public static class CompletableFutures.Instances
extends java.lang.Object

Companion class for creating Type Class instances for working with CompletableFutures

Constructor Summary

Constructors

Constructor and Description
Instances()

Method Summary

Modifier and Type	Method and Description
static <T,R> Applicative<CompletableFutureKind.µ>	applicative() import static com.aol.cyclops.hkt.jdk.CompletableFutureKind.widen; import static com.aol.cyclops.util.function.Lambda.l1; CompletableFutures.applicative() .ap(widen(asCompletableFuture(l1(this::multiplyByTwo))),widen(asCompletableFuture(3))); //[6]
static <T> Comonad<CompletableFutureKind.µ>	comonad()
static <T> Foldable<CompletableFutureKind.µ>	foldable() int sum = CompletableFutures.foldable() .foldLeft(0, (a,b)->a+b, CompletableFutureKind.widen(CompletableFuture.completedFuture(3))); //3
static <T,R> Functor<CompletableFutureKind.µ>	functor() Transform a future, mulitplying every element by 2
static <T,R> Monad<CompletableFutureKind.µ>	monad() import static com.aol.cyclops.hkt.jdk.CompletableFutureKind.widen; CompletableFutureKind<Integer> future = CompletableFutures.monad() .flatMap(i->widen(CompletableFutureX.range(0,i)), widen(CompletableFuture.completedFuture(3))) .convert(CompletableFutureKind::narrowK);
static <T> MonadPlus<CompletableFutureKind.µ>	monadPlus() CompletableFutureKind<Integer> future = CompletableFutures.<Integer>monadPlus() .plus(CompletableFutureKind.widen(CompletableFuture.completedFuture()), CompletableFutureKind.widen(CompletableFuture.completedFuture(10))) .convert(CompletableFutureKind::narrowK); //CompletableFuture.completedFuture(10))
static <T> MonadPlus<CompletableFutureKind.µ>	monadPlus(Monoid<CompletableFutureKind<T>> m) Monoid<CompletableFutureKind<Integer>> m = Monoid.of(CompletableFutureKind.widen(CompletableFuture.completedFuture()), (a,b)->a.isEmpty() ? b : a); CompletableFutureKind<Integer> future = CompletableFutures.<Integer>monadPlus(m) .plus(CompletableFutureKind.widen(CompletableFuture.completedFuture(5)), CompletableFutureKind.widen(CompletableFuture.completedFuture(10))) .convert(CompletableFutureKind::narrowK); //CompletableFuture.completedFuture(5))
static <T,R> MonadZero<CompletableFutureKind.µ>	monadZero() CompletableFutureKind<String> future = CompletableFutures.unit() .unit("hello") .transform(h->CompletableFutures.monadZero().filter((String t)->t.startsWith("he"), h)) .convert(CompletableFutureKind::narrowK); //CompletableFuture.completedFuture("hello"));
static <C2,T> Traverse<CompletableFutureKind.µ>	traverse()
static <T> Pure<CompletableFutureKind.µ>	unit() CompletableFutureKind<String> future = CompletableFutures.unit() .unit("hello") .convert(CompletableFutureKind::narrowK); //CompletableFuture.completedFuture("hello"))

Methods inherited from class java.lang.Object

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

Constructor Detail

Instances

public Instances()

Method Detail

functor

public static <T,R> Functor<CompletableFutureKind.µ> functor()

Transform a future, mulitplying every element by 2

 
  CompletableFutureKind<Integer> future = CompletableFutures.functor().map(i->i*2, CompletableFutureKind.widen(CompletableFuture.completedFuture(1,2,3));

  //[2,4,6]


 
 

An example fluent api working with CompletableFutures

 
   CompletableFutureKind<Integer> future = CompletableFutures.unit()
        .unit("hello")
        .transform(h->CompletableFutures.functor().map((String v) ->v.length(), h))
        .convert(CompletableFutureKind::narrowK);

 
 

Returns:

A functor for CompletableFutures

unit

public static <T> Pure<CompletableFutureKind.µ> unit()

 
 CompletableFutureKind<String> future = CompletableFutures.unit()
        .unit("hello")
        .convert(CompletableFutureKind::narrowK);

        //CompletableFuture.completedFuture("hello"))

 
 

Returns:

A factory for CompletableFutures

applicative

public static <T,R> Applicative<CompletableFutureKind.µ> applicative()

 
 import static com.aol.cyclops.hkt.jdk.CompletableFutureKind.widen;
 import static com.aol.cyclops.util.function.Lambda.l1;

        CompletableFutures.applicative()
        .ap(widen(asCompletableFuture(l1(this::multiplyByTwo))),widen(asCompletableFuture(3)));

 //[6]
 
 

Example fluent API

 
 CompletableFutureKind<Function<Integer,Integer>> futureFn =CompletableFutures.unit()
                                                  .unit(Lambda.l1((Integer i) ->i*2))
                                                  .convert(CompletableFutureKind::narrowK);

        CompletableFutureKind<Integer> future = CompletableFutures.unit()
        .unit("hello")
        .transform(h->CompletableFutures.functor().map((String v) ->v.length(), h))
        .transform(h->CompletableFutures.applicative().ap(futureFn, h))
        .convert(CompletableFutureKind::narrowK);

        //CompletableFuture.completedFuture("hello".length()*2))

 
 

Returns:

A zipper for CompletableFutures

monad

public static <T,R> Monad<CompletableFutureKind.µ> monad()

 
 import static com.aol.cyclops.hkt.jdk.CompletableFutureKind.widen;
 CompletableFutureKind<Integer> future  = CompletableFutures.monad()
        .flatMap(i->widen(CompletableFutureX.range(0,i)), widen(CompletableFuture.completedFuture(3)))
        .convert(CompletableFutureKind::narrowK);
 
 

Example fluent API

 
    CompletableFutureKind<Integer> future = CompletableFutures.unit()
        .unit("hello")
        .transform(h->CompletableFutures.monad().flatMap((String v) ->CompletableFutures.unit().unit(v.length()), h))
        .convert(CompletableFutureKind::narrowK);

        //CompletableFuture.completedFuture("hello".length())

 
 

Returns:

Type class with monad functions for CompletableFutures

monadZero

public static <T,R> MonadZero<CompletableFutureKind.µ> monadZero()

 
  CompletableFutureKind<String> future = CompletableFutures.unit()
        .unit("hello")
        .transform(h->CompletableFutures.monadZero().filter((String t)->t.startsWith("he"), h))
        .convert(CompletableFutureKind::narrowK);

        //CompletableFuture.completedFuture("hello"));

 
 

Returns:

A filterable monad (with default value)

monadPlus

public static <T> MonadPlus<CompletableFutureKind.µ> monadPlus()

 
  CompletableFutureKind<Integer> future = CompletableFutures.<Integer>monadPlus()
        .plus(CompletableFutureKind.widen(CompletableFuture.completedFuture()), CompletableFutureKind.widen(CompletableFuture.completedFuture(10)))
        .convert(CompletableFutureKind::narrowK);
        //CompletableFuture.completedFuture(10))

 
 

Returns:

Type class for combining CompletableFutures by concatenation

monadPlus

public static <T> MonadPlus<CompletableFutureKind.µ> monadPlus(Monoid<CompletableFutureKind<T>> m)

 
  Monoid<CompletableFutureKind<Integer>> m = Monoid.of(CompletableFutureKind.widen(CompletableFuture.completedFuture()), (a,b)->a.isEmpty() ? b : a);
        CompletableFutureKind<Integer> future = CompletableFutures.<Integer>monadPlus(m)
        .plus(CompletableFutureKind.widen(CompletableFuture.completedFuture(5)), CompletableFutureKind.widen(CompletableFuture.completedFuture(10)))
        .convert(CompletableFutureKind::narrowK);
        //CompletableFuture.completedFuture(5))

 
 

Parameters:

m - Monoid to use for combining CompletableFutures

Returns:

Type class for combining CompletableFutures

traverse

public static <C2,T> Traverse<CompletableFutureKind.µ> traverse()

Returns:

Type class for traversables with traverse / sequence operations

foldable

public static <T> Foldable<CompletableFutureKind.µ> foldable()

 
 int sum  = CompletableFutures.foldable()
        .foldLeft(0, (a,b)->a+b, CompletableFutureKind.widen(CompletableFuture.completedFuture(3)));

        //3

 
 

Returns:

Type class for folding / reduction operations

comonad

public static <T> Comonad<CompletableFutureKind.µ> comonad()