Class EitherLens
java.lang.Object
com.jnape.palatable.lambda.optics.lenses.EitherLens
Lenses for
Either
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionstatic <L,
R> Lens.Simple <Either<L, R>, Maybe<L>> _left()
Convenience static factory method for creating a lens over left values, wrapping them in aMaybe
.static <L,
R> Lens.Simple <Either<L, R>, Maybe<R>> _right()
Convenience static factory method for creating a lens over right values, wrapping them in aMaybe
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Constructor Details
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EitherLens
private EitherLens()
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Method Details
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_right
Convenience static factory method for creating a lens over right values, wrapping them in aMaybe
. When setting, aMaybe.nothing()
value means to leave theEither
unaltered, where as aMaybe.just(A)
value replaces the either with a right over theMaybe
.Note that this lens is NOT lawful, since "you get back what you put in" fails for
Maybe.nothing()
.- Type Parameters:
L
- the left parameter typeR
- the right parameter type- Returns:
- a lens that focuses on right values
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_left
Convenience static factory method for creating a lens over left values, wrapping them in aMaybe
. When setting, aMaybe.nothing()
value means to leave theEither
unaltered, where as aMaybe.just(A)
value replaces the either with a left over theMaybe
.Note that this lens is NOT lawful, since "you get back what you put in" fails for
Maybe.nothing()
.- Type Parameters:
L
- the left parameter typeR
- the right parameter type- Returns:
- a lens that focuses on left values
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