Interface Result.Binder<E>

Enclosing interface:

Result<E,T>

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public static interface Result.Binder<E>

The unwrapping handle passed to Result.binding(Function).

Calling on(Result) inside a binding block either returns the success value or aborts the whole block at the first Result.Err encountered.

Method Summary

Modifier and Type	Method	Description
default void	ensure(boolean condition, Supplier<? extends E> error)	Assert a condition with no value to bind: a guard, a permission check, an invariant.
<T> T	on(Result<E,T> result)	Unwrap a Result inside a binding block: returns the value if Result.Ok, otherwise short-circuits the enclosing block, which then evaluates to that Result.Err.
default <T> T	on(Optional<? extends T> maybe, Supplier<? extends E> ifEmpty)	Bind an Optional inside a binding block: a present value is returned, an empty Optional short-circuits the block with ifEmpty.get().

Method Details

on

<T> T on(Result<E,T> result)

Unwrap a Result inside a binding block: returns the value if Result.Ok, otherwise short-circuits the enclosing block, which then evaluates to that Result.Err. Only legal while the surrounding binding call is on the stack.

on

default <T> T on(Optional<? extends T> maybe,
 Supplier<? extends E> ifEmpty)

Bind an Optional inside a binding block: a present value is returned, an empty Optional short-circuits the block with ifEmpty.get(). Lets Optional- and Result-returning calls be sequenced together without bridging each one by hand.

var candidates = bind.on(NonEmptyList.fromList(xs), AppError.NoCandidates::new);

ensure

default void ensure(boolean condition,
 Supplier<? extends E> error)

Assert a condition with no value to bind: a guard, a permission check, an invariant. false short-circuits the enclosing block with the supplied error, exactly like binding an Err; true is a no-op.