com.jnape.palatable.lambda.optics.lenses

Class CollectionLens

java.lang.Object

com.jnape.palatable.lambda.optics.lenses.CollectionLens

public final class CollectionLens
extends Object

Lenses that operate on Collections.

Method Summary

Modifier and Type	Method and Description
static <X,CX extends Collection<X>> Lens.Simple<CX,CX>	asCopy(Fn1<? super CX,? extends CX> copyFn) Convenience static factory method for creating a lens that focuses on a copy of a Collection, given a function that creates the copy.
static <X,CX extends Collection<X>> Lens.Simple<CX,Set<X>>	asSet(Fn1<? super CX,? extends CX> copyFn) Convenience static factory method for creating a lens that focuses on an arbitrary Collection as a Set.
static <X,CX extends Collection<X>> Lens.Simple<CX,Stream<X>>	asStream(Fn1<? super CX,? extends CX> copyFn) Convenience static factory method for creating a lens that focuses on a Collection as a Stream.

Methods inherited from class java.lang.Object

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

Method Detail

asCopy

public static <X,CX extends Collection<X>> Lens.Simple<CX,CX> asCopy(Fn1<? super CX,? extends CX> copyFn)

Convenience static factory method for creating a lens that focuses on a copy of a Collection, given a function that creates the copy. Useful for composition to avoid mutating a Collection reference.

Type Parameters:

X - the collection element type

CX - the type of the collection

Parameters:

copyFn - the copying function

Returns:

a lens that focuses on a copy of CX

asSet

public static <X,CX extends Collection<X>> Lens.Simple<CX,Set<X>> asSet(Fn1<? super CX,? extends CX> copyFn)

Convenience static factory method for creating a lens that focuses on an arbitrary Collection as a Set.

Type Parameters:

X - the collection element type

CX - the type of the collection

Parameters:

copyFn - the copying function

Returns:

a lens that focuses on a Collection as a Set

asStream

public static <X,CX extends Collection<X>> Lens.Simple<CX,Stream<X>> asStream(Fn1<? super CX,? extends CX> copyFn)

Convenience static factory method for creating a lens that focuses on a Collection as a Stream.

Note that this lens is effectively lawful, though difficult to prove given the intrinsically stateful and inequitable nature of Stream.

Type Parameters:

X - the collection element type

CX - the type of the collection

Parameters:

copyFn - the copying function

Returns:

a lens that focuses on a Collection as a stream.