Package 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	Description
static final u.Optional<Boolean>	FALSE	Presents Boolean.FALSE.
static final u.Optional<Boolean>	TRUE	Presents Boolean.TRUE.

Method Summary

Modifier and Type	Method	Description
Optional<T>	__()	Deprecated. to be removed in future version.
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)
static <T> u.Optional<T>	from(Optional<T> op)
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<T>,E> supplier)
T	orElse(T other)
<E extends Exception> T	orElseGet(Throwables.Supplier<? extends T,E> other)	Or else get.
T	orElseNull()
T	orElseThrow()	Or else throw.
T	orElseThrow(String errorMessage)	Or else throw.
T	orElseThrow(String errorMessage, Object param)	Or else throw.
T	orElseThrow(String errorMessage, Object... params)	Or else throw.
T	orElseThrow(String errorMessage, Object param1, Object param2)	Or else throw.
T	orElseThrow(String errorMessage, Object param1, Object param2, Object param3)	Or else throw.
<X extends Throwable> T	orElseThrow(Supplier<? extends X> exceptionSupplier)	Or else throw.
T	orNull()	Deprecated. using orElseNull()
Stream<T>	stream()
ImmutableList<T>	toImmutableList()	To immutable list.
ImmutableSet<T>	toImmutableSet()	To immutable set.
Optional<T>	toJdkOptional()
List<T>	toList()
Set<T>	toSet()
String	toString()

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Details

TRUE

public static final u.Optional<Boolean> TRUE

Presents Boolean.TRUE.

FALSE

public static final u.Optional<Boolean> FALSE

Presents Boolean.FALSE.

Method Details

empty

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

Type Parameters:

T -

Returns:

of

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

Parameters:

value -

Returns:

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)

Parameters:

value -

Returns:

ofNullable

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

Type Parameters:

T -

Parameters:

value -

Returns:

from

public static <T> u.Optional<T> from(Optional<T> op)

Type Parameters:

T -

Parameters:

op -

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

Type Parameters:

E -

Parameters:

action -

Returns:

itself

Throws:

E - the e

ifPresentOrElse

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

If present or else.

Type Parameters:

E -

E2 -

Parameters:

action -

emptyAction -

Returns:

itself

Throws:

E - the e

E2 - the e2

filter

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

Type Parameters:

E -

Parameters:

predicate -

Returns:

Throws:

E - the e

map

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

Type Parameters:

U -

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

mapToNonNull

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

Type Parameters:

U -

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

mapToBoolean

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

Map to boolean.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

mapToChar

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

Map to char.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

mapToByte

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

Map to byte.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

mapToShort

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

Map to short.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

mapToInt

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

Map to int.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

mapToLong

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

Map to long.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

mapToFloat

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

Map to float.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

mapToDouble

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

Map to double.

Type Parameters:

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

flatMap

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

Type Parameters:

U -

E -

Parameters:

mapper -

Returns:

Throws:

E - the e

contains

public boolean contains(T element)

Parameters:

element -

Returns:

or

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

Type Parameters:

E -

Parameters:

supplier -

Returns:

Throws:

E - the e

orNull

@Deprecated
public T orNull()

Deprecated.

using orElseNull()

Returns:

orElseNull

public T orElseNull()

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

Or else get.

Type Parameters:

E -

Parameters:

other -

Returns:

Throws:

E - the e

orElseThrow

public T orElseThrow()
              throws NoSuchElementException

Or else throw.

Returns:

Throws:

NoSuchElementException - the no such element exception

orElseThrow

@Beta
public T orElseThrow(String errorMessage)
              throws NoSuchElementException

Or else throw.

Parameters:

errorMessage -

Returns:

Throws:

NoSuchElementException - the no such element exception

orElseThrow

@Beta
public T orElseThrow(String errorMessage,
 Object param)
              throws NoSuchElementException

Or else throw.

Parameters:

errorMessage -

param -

Returns:

Throws:

NoSuchElementException - the no such element exception

orElseThrow

@Beta
public T orElseThrow(String errorMessage,
 Object param1,
 Object param2)
              throws NoSuchElementException

Or else throw.

Parameters:

errorMessage -

param1 -

param2 -

Returns:

Throws:

NoSuchElementException - the no such element exception

orElseThrow

@Beta
public T orElseThrow(String errorMessage,
 Object param1,
 Object param2,
 Object param3)
              throws NoSuchElementException

Or else throw.

Parameters:

errorMessage -

param1 -

param2 -

param3 -

Returns:

Throws:

NoSuchElementException - the no such element exception

orElseThrow

@Beta
public T orElseThrow(String errorMessage,
 Object... params)
              throws NoSuchElementException

Or else throw.

Parameters:

errorMessage -

params -

Returns:

Throws:

NoSuchElementException - the no such element exception

orElseThrow

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

Or else throw.

Type Parameters:

X -

Parameters:

exceptionSupplier -

Returns:

Throws:

X - the x

stream

public Stream<T> stream()

Returns:

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:

toJdkOptional

public Optional<T> toJdkOptional()

Returns:

__

@Deprecated
public Optional<T> __()

Deprecated.

to be removed in future version.

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: