Module io.helidon.common.mapper

Package io.helidon.common.mapper

Interface OptionalValue<T>

Type Parameters:

T - type of the value

All Superinterfaces:

Value<T>

All Known Subinterfaces:

ConfigValue<T>, ConfigValue<T>

public interface OptionalValue<T>
extends Value<T>

A typed value with support for mapping (conversion) to other types.

Method Summary

Modifier and Type	Method	Description
<N> OptionalValue<N>	as(GenericType<N> type)	Convert this value to a different type using a mapper.
<N> OptionalValue<N>	as(Class<N> type)	Convert this value to a different type using a mapper.
<N> OptionalValue<N>	as(Function<? super T,? extends N> mapper)	Convert this Value to a different type using a mapper function.
default OptionalValue<Boolean>	asBoolean()	Boolean typed value.
default OptionalValue<Double>	asDouble()	Double typed value.
default OptionalValue<Integer>	asInt()	Integer typed value.
default OptionalValue<Long>	asLong()	Long typed value.
default OptionalValue<String>	asString()	String typed value.
static <T> OptionalValue<T>	create(MapperManager mapperManager, String name, GenericType<T> type, String... qualifiers)	Create an empty value.
static <T> OptionalValue<T>	create(MapperManager mapperManager, String name, Class<T> type, String... qualifiers)	Create an empty value.
static <T> OptionalValue<T>	create(MapperManager mapperManager, String name, T value, GenericType<T> type, String... qualifiers)	Create a value backed by data.
static <T> OptionalValue<T>	create(MapperManager mapperManager, String name, T value, String... qualifiers)	Create a value backed by data.
T	get()	Typed value.
default void	ifPresent(Consumer<? super T> consumer)	If a value is present, invoke the specified consumer with the value, otherwise do nothing.
default void	ifPresentOrElse(Consumer<T> action, Runnable emptyAction)	If a value is present, performs the given action with the value, otherwise performs the given empty-based action.
default boolean	isEmpty()	Return false if there is a value present, otherwise true.
default boolean	isPresent()	Return true if there is a value present, otherwise false.
default <U> Optional<U>	map(Function<? super T,? extends U> mapper)	If a value is present, apply the provided mapping function to it, and if the result is non-null, return an Optional describing the result.
default Optional<T>	or(Supplier<? extends Optional<T>> supplier)	If the underlying Optional does not have a value, set it to the Optional produced by the supplying function.
default T	orElse(T other)	Return the value if present, otherwise return other.
default T	orElseGet(Supplier<? extends T> other)	Return the value if present, otherwise invoke other and return the result of that invocation.
default T	orElseThrow()	If a value is present, returns the value, otherwise throws NoSuchElementException.
default <X extends Throwable> T	orElseThrow(Supplier<? extends X> exceptionSupplier)	Return the contained value, if present, otherwise throw an exception to be created by the provided supplier.

Methods inherited from interface io.helidon.common.mapper.Value

asOptional, filter, flatMap, get, get, getBoolean, getDouble, getInt, getLong, getString, name, stream

Method Details

create

static <T> OptionalValue<T> create(MapperManager mapperManager,
 String name,
 Class<T> type,
 String... qualifiers)

Create an empty value. Empty value is not backed by data and all of its methods consider it is empty.

Type Parameters:

T - type of the value

Parameters:

mapperManager - mapper manager to use for mapping types

name - name of the value

type - type of the value, to correctly handle mapping exceptions

qualifiers - qualifiers of the mapper

Returns:

an empty value

create

static <T> OptionalValue<T> create(MapperManager mapperManager,
 String name,
 GenericType<T> type,
 String... qualifiers)

Create an empty value. Empty value is not backed by data and all of its methods consider it is empty.

Type Parameters:

T - type of the value

Parameters:

mapperManager - mapper manager to use for mapping types

name - name of the value

type - type of the value, to correctly handle mapping exceptions

qualifiers - qualifiers of the mapper

Returns:

an empty value

create

static <T> OptionalValue<T> create(MapperManager mapperManager,
 String name,
 T value,
 String... qualifiers)

Create a value backed by data. The type of the value is "guessed" from the instance provided.

Type Parameters:

T - type of the value

Parameters:

mapperManager - mapper manager to use for mapping types

name - name of the value

value - value, must not be null

qualifiers - qualifiers of the mapper

Returns:

a value backed by data

create

static <T> OptionalValue<T> create(MapperManager mapperManager,
 String name,
 T value,
 GenericType<T> type,
 String... qualifiers)

Create a value backed by data.

Type Parameters:

T - type of the value

Parameters:

mapperManager - mapper manager to use for mapping types

name - name of the value

value - value, must not be null

type - a more precise type that could be guessed form an instance

qualifiers - qualifiers of the mapper

Returns:

a value backed by data

as

<N> OptionalValue<N> as(Class<N> type)

Description copied from interface: Value

Convert this value to a different type using a mapper.

Specified by:

as in interface Value<T>

Type Parameters:

N - type we expect

Parameters:

type - type to convert to

Returns:

converted value

as

<N> OptionalValue<N> as(GenericType<N> type)

Description copied from interface: Value

Convert this value to a different type using a mapper.

Specified by:

as in interface Value<T>

Type Parameters:

N - type we expect

Parameters:

type - type to convert to

Returns:

converted value

as

<N> OptionalValue<N> as(Function<? super T,? extends N> mapper)

Description copied from interface: Value

Convert this Value to a different type using a mapper function.

Specified by:

as in interface Value<T>

Type Parameters:

N - type of the returned Value

Parameters:

mapper - mapper to map the type of this Value to a type of the returned Value

Returns:

a new value with the new type

get

T get()

Typed value.

Specified by:

get in interface Value<T>

Returns:

direct value converted to the expected type

Throws:

NoSuchElementException - or appropriate module specific exception if the value is not present

or

default Optional<T> or(Supplier<? extends Optional<T>> supplier)

If the underlying Optional does not have a value, set it to the Optional produced by the supplying function.

Parameters:

supplier - the supplying function that produces an Optional

Returns:

returns current value using Value.asOptional() if present, otherwise value produced by the supplying function.

Throws:

NullPointerException - if the supplying function is null or produces a null result

isPresent

default boolean isPresent()

Return true if there is a value present, otherwise false.

Copied from Optional. You can get real optional from Value.asOptional().

Returns:

true if there is a value present, otherwise false

See Also:

• Optional.isPresent()

isEmpty

default boolean isEmpty()

Return false if there is a value present, otherwise true.

Copied from Optional. You can get real optional from Value.asOptional().

Returns:

false if there is a value present, otherwise true

See Also:

• ()

ifPresentOrElse

default void ifPresentOrElse(Consumer<T> action,
 Runnable emptyAction)

If a value is present, performs the given action with the value, otherwise performs the given empty-based action.

Parameters:

action - the action to be performed, if a value is present

emptyAction - the empty-based action to be performed, if no value is present

Throws:

NullPointerException - if a value is present and the given action is null, or no value is present and the given empty-based action is null.

ifPresent

default void ifPresent(Consumer<? super T> consumer)

If a value is present, invoke the specified consumer with the value, otherwise do nothing.

Copied from Optional. You can get real optional from Value.asOptional().

Parameters:

consumer - block to be executed if a value is present

Throws:

NullPointerException - if value is present and consumer is null

See Also:

• Optional.ifPresent(Consumer)

map

default <U> Optional<U> map(Function<? super T,? extends U> mapper)

If a value is present, apply the provided mapping function to it, and if the result is non-null, return an Optional describing the result. Otherwise return an empty Optional.

Type Parameters:

U - The type of the result of the mapping function

Parameters:

mapper - a mapping function to apply to the value, if present

Returns:

an Optional describing the result of applying a mapping function to the value of this Optional, if a value is present, otherwise an empty Optional

Throws:

NullPointerException - if the mapping function is null

Copied from Optional. You can get real optional from Value.asOptional().

See Also:

• Optional.map(Function)

orElse

default T orElse(T other)

Return the value if present, otherwise return other.

Copied from Optional. You can get real optional from Value.asOptional().

Parameters:

other - the value to be returned if there is no value present, may be null

Returns:

the value, if present, otherwise other

See Also:

• Optional.orElse(Object)

orElseGet

default T orElseGet(Supplier<? extends T> other)

Return the value if present, otherwise invoke other and return the result of that invocation.

Copied from Optional. You can get real optional from Value.asOptional().

Parameters:

other - a Supplier whose result is returned if no value is present

Returns:

the value if present otherwise the result of other.get()

Throws:

NullPointerException - if value is not present and other is null

See Also:

• Optional.orElseGet(Supplier)

orElseThrow

default <X extends Throwable> T orElseThrow(Supplier<? extends X> exceptionSupplier)
                                     throws X

Return the contained value, if present, otherwise throw an exception to be created by the provided supplier.

Copied from Optional. You can get real optional from Value.asOptional().

Type Parameters:

X - Type of the exception to be thrown

Parameters:

exceptionSupplier - The supplier which will return the exception to be thrown

Returns:

the present value

Throws:

X - if there is no value present

NullPointerException - if no value is present and exceptionSupplier is null

See Also:

• Optional.orElseThrow(Supplier)

orElseThrow

default T orElseThrow()

If a value is present, returns the value, otherwise throws NoSuchElementException.

Returns:

the non-null value described by this value

Throws:

NoSuchElementException - if no value is present

asBoolean

default OptionalValue<Boolean> asBoolean()

Description copied from interface: Value

Boolean typed value.

Specified by:

asBoolean in interface Value<T>

Returns:

typed value

asString

default OptionalValue<String> asString()

Description copied from interface: Value

String typed value.

Specified by:

asString in interface Value<T>

Returns:

typed value

asInt

default OptionalValue<Integer> asInt()

Description copied from interface: Value

Integer typed value.

Specified by:

asInt in interface Value<T>

Returns:

typed value

asLong

default OptionalValue<Long> asLong()

Description copied from interface: Value

Long typed value.

Specified by:

asLong in interface Value<T>

Returns:

typed value

asDouble

default OptionalValue<Double> asDouble()

Description copied from interface: Value

Double typed value.

Specified by:

asDouble in interface Value<T>

Returns:

typed value