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.

Since:

1.0

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