Package com.jnape.palatable.lambda.monoid.builtin

Class MergeHMaps

java.lang.Object

com.jnape.palatable.lambda.monoid.builtin.MergeHMaps

All Implemented Interfaces:

Fn1<HMap,Fn1<HMap,HMap>>, Fn2<HMap,HMap,HMap>, Applicative<Fn1<HMap,HMap>,Fn1<HMap,?>>, Cartesian<HMap,Fn1<HMap,HMap>,Fn1<?,?>>, Cocartesian<HMap,Fn1<HMap,HMap>,Fn1<?,?>>, Contravariant<HMap,Profunctor<?,Fn1<HMap,HMap>,Fn1<?,?>>>, Functor<Fn1<HMap,HMap>,Fn1<HMap,?>>, Profunctor<HMap,Fn1<HMap,HMap>,Fn1<?,?>>, Monad<Fn1<HMap,HMap>,Fn1<HMap,?>>, MonadReader<HMap,Fn1<HMap,HMap>,Fn1<HMap,?>>, MonadRec<Fn1<HMap,HMap>,Fn1<HMap,?>>, MonadWriter<HMap,Fn1<HMap,HMap>,Fn1<HMap,?>>, Monoid<HMap>, Semigroup<HMap>

public final class MergeHMaps
extends Object
implements Monoid<HMap>

A Monoid instance formed by merging HMaps using the chosen TypeSafeKey -> Semigroup mappings, defaulting to Last in case no Semigroup has been chosen for a given TypeSafeKey.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static interface	MergeHMaps.Φ<R>

Field Summary

Fields

Modifier and Type	Field	Description
private final Map<TypeSafeKey<?,?>,Fn2<HMap,HMap,HMap>>	bindings
private final MergeHMaps.Φ<Fn2<HMap,HMap,HMap>>	defaultBinding

Constructor Summary

Constructors

Modifier	Constructor	Description
private	MergeHMaps(Map<TypeSafeKey<?,?>,Fn2<HMap,HMap,HMap>> bindings, MergeHMaps.Φ<Fn2<HMap,HMap,HMap>> defaultBinding)

Method Summary

Modifier and Type	Method	Description
HMap	checkedApply(HMap x, HMap y)
<B> HMap	foldMap(Fn1<? super B,? extends HMap> fn, Iterable<B> bs)	Homomorphism combined with catamorphism.
HMap	identity()	The identity element of this monoid.
<A> MergeHMaps	key(TypeSafeKey<?,A> key, Semigroup<A> semigroup)
private static <A> Fn2<HMap,HMap,HMap>	merge(TypeSafeKey<?,A> key, Semigroup<Maybe<A>> semigroup)
static MergeHMaps	mergeHMaps()

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.jnape.palatable.lambda.functions.Fn1

andThen, carry, cartesian, censor, choose, cocartesian, diMap, diMapR, discardL, flatMap, fmap, lazyZip, listens, local, pure, self, thunk, toFunction, trampolineM, zip, zip

Methods inherited from interface com.jnape.palatable.lambda.functions.Fn2

apply, apply, checkedApply, compose, contraMap, diMapL, discardR, toBiFunction, uncurry, widen

Methods inherited from interface com.jnape.palatable.lambda.functor.Functor

coerce

Methods inherited from interface com.jnape.palatable.lambda.monoid.Monoid

flip, foldLeft, foldRight, reduceLeft, reduceRight

Field Details

bindings

private final Map<TypeSafeKey<?,?>,Fn2<HMap,HMap,HMap>> bindings

defaultBinding

private final MergeHMaps.Φ<Fn2<HMap,HMap,HMap>> defaultBinding

Constructor Details

MergeHMaps

private MergeHMaps(Map<TypeSafeKey<?,?>,Fn2<HMap,HMap,HMap>> bindings,
 MergeHMaps.Φ<Fn2<HMap,HMap,HMap>> defaultBinding)

Method Details

key

public <A> MergeHMaps key(TypeSafeKey<?,A> key,
 Semigroup<A> semigroup)

identity

public HMap identity()

Description copied from interface: Monoid

The identity element of this monoid.

Specified by:

identity in interface Monoid<HMap>

Returns:

the identity

checkedApply

public HMap checkedApply(HMap x,
 HMap y)
                  throws Throwable

Specified by:

checkedApply in interface Fn2<HMap,HMap,HMap>

Throws:

Throwable

foldMap

public <B> HMap foldMap(Fn1<? super B,? extends HMap> fn,
 Iterable<B> bs)

Description copied from interface: Monoid

Homomorphism combined with catamorphism. Convert an Iterable<B> to an Iterable<A> (that is, an Iterable of elements this monoid is formed over), then reduce the result from left to right. Under algebraic data types, this is isomorphic to a flatMap.

Specified by:

foldMap in interface Monoid<HMap>

Type Parameters:

B - the input Iterable element type

Parameters:

fn - the mapping function from A to B

bs - the Iterable of Bs

Returns:

the folded result under this Monoid

See Also:

• Map
• Monoid.reduceLeft(Iterable)

mergeHMaps

public static MergeHMaps mergeHMaps()

merge

private static <A> Fn2<HMap,HMap,HMap> merge(TypeSafeKey<?,A> key,
 Semigroup<Maybe<A>> semigroup)