com.vaadin.flow.data.binder

Interface Result<R>

Type Parameters:

R - the result value type

All Superinterfaces:

Serializable

public interface Result<R>
extends Serializable

Represents the result of an operation that might fail, such as type conversion. A result may contain either a value, signifying a successful operation, or an error message in case of a failure.

Result instances are created using the factory methods ok(Object) and error(String), denoting success and failure respectively.

Unless otherwise specified, Result method arguments cannot be null.

Method Summary

Modifier and Type	Method and Description
static <R> Result<R>	error(String message) Returns a failure result wrapping the given error message.
<S> Result<S>	flatMap(SerializableFunction<R,Result<S>> mapper) If this Result has a value, applies the given Result-returning function to the value.
Optional<String>	getMessage() Returns an Optional of the result message, or an empty Optional if none.
<X extends Throwable> R	getOrThrow(SerializableFunction<String,? extends X> exceptionProvider) Return the value, if the result denotes success, otherwise throw an exception to be created by the provided supplier.
void	handle(SerializableConsumer<R> ifOk, SerializableConsumer<String> ifError) Invokes either the first callback or the second one, depending on whether this Result denotes a success or a failure, respectively.
default void	ifError(SerializableConsumer<String> consumer) Applies the consumer if result is an error.
default void	ifOk(SerializableConsumer<R> consumer) Applies the consumer if result is not an error.
boolean	isError() Checks if the result denotes an error.
default <S> Result<S>	map(SerializableFunction<R,S> mapper) If this Result has a value, returns a Result of applying the given function to the value.
static <R> Result<R>	of(SerializableSupplier<R> supplier, SerializableFunction<Exception,String> onError) Returns a Result representing the result of invoking the given supplier.
static <R> Result<R>	ok(R value) Returns a successful result wrapping the given value.

Method Detail

ok

static <R> Result<R> ok(R value)

Returns a successful result wrapping the given value.

Type Parameters:

R - the result value type

Parameters:

value - the result value, can be null

Returns:

a successful result

error

static <R> Result<R> error(String message)

Returns a failure result wrapping the given error message.

Type Parameters:

R - the result value type

Parameters:

message - the error message

Returns:

a failure result

of

static <R> Result<R> of(SerializableSupplier<R> supplier,
                        SerializableFunction<Exception,String> onError)

Returns a Result representing the result of invoking the given supplier. If the supplier returns a value, returns a Result.ok of the value; if an exception is thrown, returns the message in a Result.error.

Type Parameters:

R - the result value type

Parameters:

supplier - the supplier to run

onError - the function to provide the error message

Returns:

the result of invoking the supplier

map

default <S> Result<S> map(SerializableFunction<R,S> mapper)

If this Result has a value, returns a Result of applying the given function to the value. Otherwise, returns a Result bearing the same error as this one. Note that any exceptions thrown by the mapping function are not wrapped but allowed to propagate.

Type Parameters:

S - the type of the mapped value

Parameters:

mapper - the mapping function

Returns:

the mapped result

flatMap

<S> Result<S> flatMap(SerializableFunction<R,Result<S>> mapper)

If this Result has a value, applies the given Result-returning function to the value. Otherwise, returns a Result bearing the same error as this one. Note that any exceptions thrown by the mapping function are not wrapped but allowed to propagate.

Type Parameters:

S - the type of the mapped value

Parameters:

mapper - the mapping function

Returns:

the mapped result

handle

void handle(SerializableConsumer<R> ifOk,
            SerializableConsumer<String> ifError)

Invokes either the first callback or the second one, depending on whether this Result denotes a success or a failure, respectively.

Parameters:

ifOk - the function to call if success

ifError - the function to call if failure

ifOk

default void ifOk(SerializableConsumer<R> consumer)

Applies the consumer if result is not an error.

Parameters:

consumer - consumer to apply in case it's not an error

ifError

default void ifError(SerializableConsumer<String> consumer)

Applies the consumer if result is an error.

Parameters:

consumer - consumer to apply in case it's an error

isError

boolean isError()

Checks if the result denotes an error.

Returns:

true if the result denotes an error, false otherwise

getMessage

Optional<String> getMessage()

Returns an Optional of the result message, or an empty Optional if none.

Returns:

the optional message

getOrThrow

<X extends Throwable> R getOrThrow(SerializableFunction<String,? extends X> exceptionProvider)
                            throws X extends Throwable

Return the value, if the result denotes success, otherwise throw an exception to be created by the provided supplier.

Type Parameters:

X - Type of the exception to be thrown

Parameters:

exceptionProvider - The provider which will return the exception to be thrown based on the given error message

Returns:

the value

Throws:

X - if this result denotes an error

X extends Throwable