Package io.vavr.control

Class Option.None<T>

java.lang.Object

io.vavr.control.Option.None<T>

Type Parameters:

T - The type of the optional value.

All Implemented Interfaces:

Option<T>, Value<T>, Serializable, Iterable<T>

Enclosing interface:

Option<T>

public static final class Option.None<T>
extends Object
implements Option<T>, Serializable

None is a singleton representation of the undefined Option.

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface io.vavr.control.Option

Option.None<T>, Option.Some<T>

Field Summary

Fields

Modifier and Type	Field	Description
private static final Option.None<?>	INSTANCE	The singleton instance of None.
private static final long	serialVersionUID

Constructor Summary

Constructors

Modifier	Constructor	Description
private	None()	Hidden constructor.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)	Clarifies that values have a proper equals() method implemented.
T	get()	Returns the value contained in this Some, or throws if this is None.
int	hashCode()	Clarifies that values have a proper hashCode() method implemented.
boolean	isEmpty()	Checks whether this Option is empty.
private Object	readResolve()	Instance control for object serialization.
String	stringPrefix()	Returns the name of this Value type, which is used by toString().
String	toString()	Clarifies that values have a proper toString() method implemented.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface io.vavr.control.Option

collect, filter, flatMap, fold, getOrElse, getOrElse, getOrElseThrow, isAsync, isDefined, isLazy, isSingleValued, iterator, map, mapTo, mapToVoid, mapTry, onEmpty, orElse, orElse, peek, transform

Methods inherited from interface io.vavr.Value

collect, collect, contains, corresponds, eq, exists, forAll, forEach, getOrElseTry, getOrNull, out, out, spliterator, stderr, stdout, toArray, toCharSeq, toCompletableFuture, toEither, toEither, toInvalid, toInvalid, toJavaArray, toJavaArray, toJavaArray, toJavaCollection, toJavaList, toJavaList, toJavaMap, toJavaMap, toJavaMap, toJavaOptional, toJavaParallelStream, toJavaSet, toJavaSet, toJavaStream, toLeft, toLeft, toLinkedMap, toLinkedMap, toLinkedSet, toList, toMap, toMap, toOption, toPriorityQueue, toPriorityQueue, toQueue, toRight, toRight, toSet, toSortedMap, toSortedMap, toSortedMap, toSortedMap, toSortedSet, toSortedSet, toStream, toTree, toTree, toTry, toTry, toValid, toValid, toValidation, toValidation, toVector

Field Details

serialVersionUID

private static final long serialVersionUID

See Also:

• Constant Field Values

INSTANCE

private static final Option.None<?> INSTANCE

The singleton instance of None.

Constructor Details

None

private None()

Hidden constructor.

Method Details

get

public T get()

Description copied from interface: Option

Returns the value contained in this Some, or throws if this is None.

Specified by:

get in interface Option<T>

Specified by:

get in interface Value<T>

Returns:

the contained value

isEmpty

public boolean isEmpty()

Description copied from interface: Option

Checks whether this Option is empty.

Specified by:

isEmpty in interface Option<T>

Specified by:

isEmpty in interface Value<T>

Returns:

true if this is None, false if this is Some

equals

public boolean equals(Object o)

Description copied from interface: Value

Clarifies that values have a proper equals() method implemented.

See Object.equals(Object).

Specified by:

equals in interface Option<T>

Specified by:

equals in interface Value<T>

Overrides:

equals in class Object

Parameters:

o - An object

Returns:

true, if this equals o, false otherwise

hashCode

public int hashCode()

Description copied from interface: Value

Clarifies that values have a proper hashCode() method implemented.

See Object.hashCode().

Specified by:

hashCode in interface Option<T>

Specified by:

hashCode in interface Value<T>

Overrides:

hashCode in class Object

Returns:

The hashcode of this object

stringPrefix

public String stringPrefix()

Description copied from interface: Value

Returns the name of this Value type, which is used by toString().

Specified by:

stringPrefix in interface Value<T>

Returns:

This type name.

toString

public String toString()

Description copied from interface: Value

Clarifies that values have a proper toString() method implemented.

See Object.toString().

Specified by:

toString in interface Option<T>

Specified by:

toString in interface Value<T>

Overrides:

toString in class Object

Returns:

A String representation of this object

readResolve

private Object readResolve()

Instance control for object serialization.

Returns:

The singleton instance of None.

See Also:

• Serializable