Interface Result<T extends @UnknownNullability Object>

Type Parameters:

T - the type, can be nullable.

All Known Implementing Classes:

Result.Error, Result.Ok

public sealed interface Result<T extends @UnknownNullability Object>
permits Result.Ok<T>, Result.Error<T>

Results are used in Encoder and Decoder to primarily function as a way of passing back exceptions as values.
They have two states Result.Ok and Result.Error, you can use pattern matching to extract the values or use some of the helper methods provided like orElseThrow() or mapResult(Function).
To construct simply just do new Result.Ok<>(value) and new Result.Error<>("Error message!")
You should not rely on the identity of results as they are value candidates.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static final record	Result.Error<T>	Represents the Result was a failure.
static final record	Result.Ok<T extends @UnknownNullability Object>	Represents the Result was successful.

Method Summary

Modifier and Type	Method	Description
default <S> Result.Error<S>	cast()	Casts the error to any type if present.
default <S extends @UnknownNullability Object> Result<S>	map(Function<T, Result<S>> mapper)	Map the Result.Ok result into the mapper function that creates a new result.
default Result<T>	mapError(Function<String,String> mapper)	Maps the Result.Error result to the mapper function and creates a new Result.Error result Otherwise, returns Result.Ok.
default <S extends @UnknownNullability Object> Result<S>	mapResult(Function<T,S> mapper)	Maps the Result.Ok result to the mapper function and creates a new Result.Ok result Otherwise, returns the error.
default @UnknownNullability T	orElse(@UnknownNullability T other)	If the resultant is not Result.Ok, returns the other value
default T	orElseThrow()	Attempts to get the value inside Result.Ok or throws.
default T	orElseThrow(String message)	Attempts to get the value inside Result.Ok or throws.

Method Details

map

@Contract(pure=true)
default <S extends @UnknownNullability Object>
Result<S> map(Function<T, Result<S>> mapper)

Map the Result.Ok result into the mapper function that creates a new result. Otherwise, returns the error.

Type Parameters:

S - the type of the result.

Parameters:

mapper - the new result

Returns:

the new result or the error.

mapResult

@Contract(pure=true)
default <S extends @UnknownNullability Object>
Result<S> mapResult(Function<T,S> mapper)

Maps the Result.Ok result to the mapper function and creates a new Result.Ok result Otherwise, returns the error.
Similar to map(Function) but instead constructs the result instead.

Type Parameters:

S - the type of the result.

Parameters:

mapper - the new result

Returns:

the new result or the error.

mapError

@Contract(pure=true)
default Result<T> mapError(Function<String,String> mapper)

Maps the Result.Error result to the mapper function and creates a new Result.Error result Otherwise, returns Result.Ok.
Similar to map(Function) but instead constructs the result instead.

Parameters:

mapper - the new result

Returns:

the new result or the error.

orElse

@Contract(pure=true)
default @UnknownNullability T orElse(@UnknownNullability T other)

If the resultant is not Result.Ok, returns the other value

Parameters:

other - value to be returned

Returns:

the resultant

orElseThrow

@Contract(pure=true)
default T orElseThrow()

Attempts to get the value inside Result.Ok or throws.

Returns:

the value

Throws:

IllegalStateException - if this instance of Result.Error

orElseThrow

@Contract(pure=true)
default T orElseThrow(String message)

Attempts to get the value inside Result.Ok or throws.

Parameters:

message - the message prefix

Returns:

the value

Throws:

IllegalStateException - if this instance of Result.Error

cast

@Contract(pure=true)
default <S> Result.Error<S> cast()

Casts the error to any type if present.
Useful to return the error if it is not the correct type.

Type Parameters:

S - the new result type

Returns:

the error

Throws:

ClassCastException - if the result is not Result.Error