co.unruly.control.result

Interface Transformers

public interface Transformers

A collection of functions which take a Result and return a Result.

Method Summary

Modifier and Type	Method and Description
static <IS,OS,F,OF extends F> Function<Result<IS,F>,Result<OS,F>>	attempt(Function<IS,Result<OS,OF>> mappingFunction) Returns a function which takes a Result and, if it's a success, applies the provided function to that success - generating a new Result - and returns that Result.
static <S,F> Function<Result<S,F>,Result<F,S>>	invert() Returns a function which takes a Result, and converts failures to successes and vice versa.
static <S,F> Function<Result<Result<S,F>,F>,Result<S,F>>	mergeFailures() Returns a function which takes a Result whose success type is itself a Result, and merges the failure cases so we have a flat Result.
static <S,F1,F2> Function<Result<Result<S,F1>,F2>,Result<S,F1>>	mergeFailures(Function<F2,F1> failureMapper) Returns a function which takes a Result whose success type is itself a Result, and merges the failure cases so we have a flat Result.
static <S,IF,OF> Function<Result<S,IF>,Result<S,OF>>	onFailure(Function<IF,OF> mappingFunction) Returns a function which takes a Result and, if it's a failure, applies the provided function to that failure.
static <S,F> ConsumableFunction<Result<S,F>>	onFailureDo(Consumer<F> consumer) Returns a consumer which takes a Result and, if it's a failure, passes it to the provided consumer
static <IS,OS,F> Function<Result<IS,F>,Result<OS,F>>	onSuccess(Function<IS,OS> mappingFunction) Returns a function which takes a Result and, if it's a success, applies the mapping value to that success, otherwise returning the original failure.
static <S,F> ConsumableFunction<Result<S,F>>	onSuccessDo(Consumer<S> consumer) Returns a Consumer which takes a Result and, if it's a Success, passes it to the provided consumer.
static <IS,OS,X extends Exception> Function<Result<IS,Exception>,Result<OS,Exception>>	onSuccessTry(ThrowingLambdas.ThrowingFunction<IS,OS,X> throwingFunction) Returns a function which takes a Result with an Exception failure type and, if it's a success, applies the mapping value to that success, returning a new success unless an exception is thrown, when it returns a failure of that exception.
static <IS,OS,F,X extends Exception> Function<Result<IS,F>,Result<OS,F>>	onSuccessTry(ThrowingLambdas.ThrowingFunction<IS,OS,X> throwingFunction, Function<Exception,F> exceptionMapper) Returns a function which takes a Result and, if it's a success, applies the mapping value to that success, returning a new success unless an exception is thrown, when it returns a failure of the exception-mapper applied to the exception.
static <S,IF,OF,OS extends S> Function<Result<S,IF>,Result<S,OF>>	recover(Function<IF,Result<OS,OF>> recoveryFunction) Returns a function which takes a Result and, if it's a failure, applies the provided function to that failure - generating a new Result - and returns that Result.
static <S,F> Function<Result<Stream<S>,F>,Stream<Result<S,F>>>	unwrapSuccesses() Takes a Result of a Stream as a success or a single failure, and returns a Stream of Results containing all the successes, or the single failure.

Method Detail

onSuccess

static <IS,OS,F> Function<Result<IS,F>,Result<OS,F>> onSuccess(Function<IS,OS> mappingFunction)

Returns a function which takes a Result and, if it's a success, applies the mapping value to that success, otherwise returning the original failure.

onSuccessDo

static <S,F> ConsumableFunction<Result<S,F>> onSuccessDo(Consumer<S> consumer)

Returns a Consumer which takes a Result and, if it's a Success, passes it to the provided consumer.

onSuccessTry

static <IS,OS,X extends Exception> Function<Result<IS,Exception>,Result<OS,Exception>> onSuccessTry(ThrowingLambdas.ThrowingFunction<IS,OS,X> throwingFunction)

Returns a function which takes a Result with an Exception failure type and, if it's a success, applies the mapping value to that success, returning a new success unless an exception is thrown, when it returns a failure of that exception. If the input was a failure, it returns that failure.

onSuccessTry

static <IS,OS,F,X extends Exception> Function<Result<IS,F>,Result<OS,F>> onSuccessTry(ThrowingLambdas.ThrowingFunction<IS,OS,X> throwingFunction,
                                                                                      Function<Exception,F> exceptionMapper)

Returns a function which takes a Result and, if it's a success, applies the mapping value to that success, returning a new success unless an exception is thrown, when it returns a failure of the exception-mapper applied to the exception. If the input was a failure, it returns that failure.

attempt

static <IS,OS,F,OF extends F> Function<Result<IS,F>,Result<OS,F>> attempt(Function<IS,Result<OS,OF>> mappingFunction)

Returns a function which takes a Result and, if it's a success, applies the provided function to that success - generating a new Result - and returns that Result. Otherwise, returns the original failure.

onFailure

static <S,IF,OF> Function<Result<S,IF>,Result<S,OF>> onFailure(Function<IF,OF> mappingFunction)

Returns a function which takes a Result and, if it's a failure, applies the provided function to that failure. Otherwise, returns the original success.

onFailureDo

static <S,F> ConsumableFunction<Result<S,F>> onFailureDo(Consumer<F> consumer)

Returns a consumer which takes a Result and, if it's a failure, passes it to the provided consumer

unwrapSuccesses

static <S,F> Function<Result<Stream<S>,F>,Stream<Result<S,F>>> unwrapSuccesses()

Takes a Result of a Stream as a success or a single failure, and returns a Stream of Results containing all the successes, or the single failure. The main use-case for this is to follow mapping over tryTo() on a function which was designed to be flat-mapped over.

recover

static <S,IF,OF,OS extends S> Function<Result<S,IF>,Result<S,OF>> recover(Function<IF,Result<OS,OF>> recoveryFunction)

Returns a function which takes a Result and, if it's a failure, applies the provided function to that failure - generating a new Result - and returns that Result. Otherwise, return the original success.

invert

static <S,F> Function<Result<S,F>,Result<F,S>> invert()

Returns a function which takes a Result, and converts failures to successes and vice versa.

mergeFailures

static <S,F> Function<Result<Result<S,F>,F>,Result<S,F>> mergeFailures()

Returns a function which takes a Result whose success type is itself a Result, and merges the failure cases so we have a flat Result. Note that *most of the time* this shouldn't be required, and indicates using onSuccess() when attempt() would be more appropriate. There are some situations though where we do end up with constructs like this: one example is when a function which returns a Result can throw exceptions (eg, when a Result-returning handler is passed into a database context). Passing that call into a tryTo() will yield a success type of the inner Result, wrapped in an outer Result for the tryTo(). If the failure types of the inner and outer failure types do not match, you'll need to either first convert the failures of the outer Result or use the overload which maps the failures of the inner Result.

mergeFailures

static <S,F1,F2> Function<Result<Result<S,F1>,F2>,Result<S,F1>> mergeFailures(Function<F2,F1> failureMapper)

Returns a function which takes a Result whose success type is itself a Result, and merges the failure cases so we have a flat Result. Note that *most of the time* this shouldn't be required, and indicates using onSuccess() when attempt() would be more appropriate. There are some situations though where we do end up with constructs like this: one example is when a function which returns a Result can throw exceptions (eg, when a Result-returning handler is passed into a database context). Passing that call into a tryTo() will yield a success type of the inner Result, wrapped in an outer Result for the tryTo(). In these cases, it's more likely the inner failure type is domain-specific, so the default approach is to map the outer failure to the inner failure and then merge.