Package com.vaadin.data

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:
    8.0

    • 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