com.landawn.abacus.util

Class u.Optional<T>

java.lang.Object

com.landawn.abacus.util.u.Optional<T>

Type Parameters:

T -

All Implemented Interfaces:

Immutable

Enclosing class:

u

@Immutable
public static final class u.Optional<T>
extends Object
implements Immutable

The Class Optional.

Field Summary

Fields

Modifier and Type	Field and Description
static u.Optional<Boolean>	FALSE Presents Boolean.FALSE.
static u.Optional<Boolean>	TRUE Presents Boolean.TRUE.

Method Summary

Modifier and Type	Method and Description
boolean	contains(T element)
static <T> u.Optional<T>	empty()
boolean	equals(Object obj)
<E extends Exception> u.Optional<T>	filter(Throwables.Predicate<? super T,E> predicate)
<U,E extends Exception> u.Optional<U>	flatMap(Throwables.Function<? super T,u.Optional<U>,E> mapper)
T	get()
int	hashCode()
<E extends Exception> u.Optional<T>	ifPresent(Throwables.Consumer<? super T,E> action)
<E extends Exception,E2 extends Exception> u.Optional<T>	ifPresentOrElse(Throwables.Consumer<? super T,E> action, Throwables.Runnable<E2> emptyAction) If present or else.
boolean	isEmpty() Checks if is empty.
boolean	isPresent() Checks if is present.
<U,E extends Exception> u.Nullable<U>	map(Throwables.Function<? super T,? extends U,E> mapper)
<E extends Exception> u.OptionalBoolean	mapToBoolean(Throwables.ToBooleanFunction<? super T,E> mapper) Map to boolean.
<E extends Exception> u.OptionalByte	mapToByte(Throwables.ToByteFunction<? super T,E> mapper) Map to byte.
<E extends Exception> u.OptionalChar	mapToChar(Throwables.ToCharFunction<? super T,E> mapper) Map to char.
<E extends Exception> u.OptionalDouble	mapToDouble(Throwables.ToDoubleFunction<? super T,E> mapper) Map to double.
<E extends Exception> u.OptionalFloat	mapToFloat(Throwables.ToFloatFunction<? super T,E> mapper) Map to float.
<E extends Exception> u.OptionalInt	mapToInt(Throwables.ToIntFunction<? super T,E> mapper) Map to int.
<E extends Exception> u.OptionalLong	mapToLong(Throwables.ToLongFunction<? super T,E> mapper) Map to long.
<U,E extends Exception> u.Optional<U>	mapToNonNull(Throwables.Function<? super T,? extends U,E> mapper)
<E extends Exception> u.OptionalShort	mapToShort(Throwables.ToShortFunction<? super T,E> mapper) Map to short.
static u.Optional<String>	of(String value)
static <T> u.Optional<T>	of(T value)
static u.Optional<String>	ofNullable(String value)
static <T> u.Optional<T>	ofNullable(T value)
<E extends Exception> u.Optional<T>	or(Throwables.Supplier<u.Optional<? extends T>,E> supplier)
T	orElse(T other)
<E extends Exception> T	orElseGet(Throwables.Supplier<? extends T,E> other) Or else get.
T	orElseThrow() Or else throw.
<X extends Throwable> T	orElseThrow(Supplier<? extends X> exceptionSupplier) Or else throw.
T	orNull()
ImmutableList<T>	toImmutableList() To immutable list.
ImmutableSet<T>	toImmutableSet() To immutable set.
List<T>	toList()
Set<T>	toSet()
String	toString()

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

TRUE

public static final u.Optional<Boolean> TRUE

Presents Boolean.TRUE.

FALSE

public static final u.Optional<Boolean> FALSE

Presents Boolean.FALSE.

Method Detail

empty

public static <T> u.Optional<T> empty()

Type Parameters:

T -

Returns:

of

public static u.Optional<String> of(String value)

of

public static <T> u.Optional<T> of(T value)

Type Parameters:

T -

Parameters:

value -

Returns:

ofNullable

public static u.Optional<String> ofNullable(String value)

ofNullable

public static <T> u.Optional<T> ofNullable(T value)

Type Parameters:

T -

Parameters:

value -

Returns:

get

public T get()
      throws NoSuchElementException

Returns:

Throws:

NoSuchElementException - the no such element exception

isPresent

public boolean isPresent()

Checks if is present.

Returns:

true, if is present

isEmpty

public boolean isEmpty()

Checks if is empty.

Returns:

true, if is empty

ifPresent

public <E extends Exception> u.Optional<T> ifPresent(Throwables.Consumer<? super T,E> action)
                                              throws E extends Exception

Type Parameters:

E -

Parameters:

action -

Returns:

itself

Throws:

E - the e

E extends Exception

ifPresentOrElse

public <E extends Exception,E2 extends Exception> u.Optional<T> ifPresentOrElse(Throwables.Consumer<? super T,E> action,
                                                                                Throwables.Runnable<E2> emptyAction)
                                                                         throws E extends Exception,
                                                                                E2 extends Exception

If present or else.

Type Parameters:

E -

E2 -

Parameters:

action -

emptyAction -

Returns:

itself

Throws:

E - the e

E2 - the e2

E extends Exception

filter

public <E extends Exception> u.Optional<T> filter(Throwables.Predicate<? super T,E> predicate)
                                           throws E extends Exception

Type Parameters:

E -

Parameters:

predicate -

Returns:

Throws:

E - the e

E extends Exception

map

public <U,E extends Exception> u.Nullable<U> map(Throwables.Function<? super T,? extends U,E> mapper)
                                          throws E extends Exception

Type Parameters:

U -

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

E extends Exception

mapToNonNull

public <U,E extends Exception> u.Optional<U> mapToNonNull(Throwables.Function<? super T,? extends U,E> mapper)
                                                   throws E extends Exception

Type Parameters:

U -

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

E extends Exception

mapToBoolean

public <E extends Exception> u.OptionalBoolean mapToBoolean(Throwables.ToBooleanFunction<? super T,E> mapper)
                                                     throws E extends Exception

Map to boolean.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

E extends Exception

mapToChar

public <E extends Exception> u.OptionalChar mapToChar(Throwables.ToCharFunction<? super T,E> mapper)
                                               throws E extends Exception

Map to char.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

E extends Exception

mapToByte

public <E extends Exception> u.OptionalByte mapToByte(Throwables.ToByteFunction<? super T,E> mapper)
                                               throws E extends Exception

Map to byte.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

E extends Exception

mapToShort

public <E extends Exception> u.OptionalShort mapToShort(Throwables.ToShortFunction<? super T,E> mapper)
                                                 throws E extends Exception

Map to short.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

E extends Exception

mapToInt

public <E extends Exception> u.OptionalInt mapToInt(Throwables.ToIntFunction<? super T,E> mapper)
                                             throws E extends Exception

Map to int.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

E extends Exception

mapToLong

public <E extends Exception> u.OptionalLong mapToLong(Throwables.ToLongFunction<? super T,E> mapper)
                                               throws E extends Exception

Map to long.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

E extends Exception

mapToFloat

public <E extends Exception> u.OptionalFloat mapToFloat(Throwables.ToFloatFunction<? super T,E> mapper)
                                                 throws E extends Exception

Map to float.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

E extends Exception

mapToDouble

public <E extends Exception> u.OptionalDouble mapToDouble(Throwables.ToDoubleFunction<? super T,E> mapper)
                                                   throws E extends Exception

Map to double.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

E extends Exception

flatMap

public <U,E extends Exception> u.Optional<U> flatMap(Throwables.Function<? super T,u.Optional<U>,E> mapper)
                                              throws E extends Exception

Type Parameters:

U -

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

E extends Exception

contains

public boolean contains(T element)

or

public <E extends Exception> u.Optional<T> or(Throwables.Supplier<u.Optional<? extends T>,E> supplier)
                                       throws E extends Exception

Type Parameters:

E -

Parameters:

supplier -

Returns:

Throws:

E - the e

E extends Exception

orNull

public T orNull()

Returns:

orElse

public T orElse(T other)

Parameters:

other -

Returns:

orElseGet

public <E extends Exception> T orElseGet(Throwables.Supplier<? extends T,E> other)
                                  throws E extends Exception

Or else get.

Type Parameters:

E -

Parameters:

other -

Returns:

Throws:

E - the e

E extends Exception

orElseThrow

public T orElseThrow()
              throws NoSuchElementException

Or else throw.

Returns:

Throws:

NoSuchElementException - the no such element exception

orElseThrow

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

Or else throw.

Type Parameters:

X -

Parameters:

exceptionSupplier -

Returns:

Throws:

X - the x

X extends Throwable

toList

public List<T> toList()

Returns:

toSet

public Set<T> toSet()

Returns:

toImmutableList

public ImmutableList<T> toImmutableList()

To immutable list.

Returns:

toImmutableSet

public ImmutableSet<T> toImmutableSet()

To immutable set.

Returns:

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

Parameters:

obj -

Returns:

hashCode

public int hashCode()

Overrides:

hashCode in class Object

Returns:

toString

public String toString()

Overrides:

toString in class Object

Returns: