javascalautils

Class None<T>

java.lang.Object

javascalautils.None<T>

Type Parameters:

T - The type of the value represented by this instance

All Implemented Interfaces:

Serializable, Iterable<T>, Option<T>

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

Represents an empty Option.

Since:

1.0

Author:

Peter Nerg

See Also:

Serialized Form

Field Summary

Fields inherited from interface javascalautils.Option

DEFAULT_NONE

Constructor Summary

Constructors

Constructor and Description
None()

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object other) Always returns true as None is stateless comparing it to some other None is therefore always the same.
boolean	exists(java.util.function.Predicate<T> p) Always returns false.
T	get() Always throws NoSuchElementException since None cannot hold any value.
T	getOrElse(java.util.function.Supplier<T> s) Always the value provided by the supplier.
int	hashCode() Always returns 0 as None is stateless and has no value.
<R> Option<R>	map(java.util.function.Function<T,R> f) Always returns this.
Option<T>	orElse(java.util.function.Supplier<Option<T>> s) Always the value provided by the supplier.
java.util.stream.Stream<T>	stream() Always returns an empty stream.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface javascalautils.Option

apply, asOptional, contains, count, empty, filter, filterNot, forall, isDefined, isEmpty, iterator, ofOptional, orNull

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

None

public None()

Method Detail

get

public T get()

Always throws NoSuchElementException since None cannot hold any value.

Specified by:

get in interface Option<T>

Returns:

The value of the Option

getOrElse

public T getOrElse(java.util.function.Supplier<T> s)

Always the value provided by the supplier.

Specified by:

getOrElse in interface Option<T>

Parameters:

s - The supplier to use in case this is a None

Returns:

The value of the Option or the value provided by the supplier

exists

public boolean exists(java.util.function.Predicate<T> p)

Always returns false.

Specified by:

exists in interface Option<T>

Parameters:

p - The predicate

Returns:

If the predicate matches

map

public <R> Option<R> map(java.util.function.Function<T,R> f)

Always returns this.

Specified by:

map in interface Option<T>

Type Parameters:

R - The type for the return value from the function

Parameters:

f - The function to use

Returns:

The Option containing the mapped value

orElse

public Option<T> orElse(java.util.function.Supplier<Option<T>> s)

Always the value provided by the supplier.

Specified by:

orElse in interface Option<T>

Parameters:

s - The supplier to use in case of None

Returns:

The value provided by the supplier

stream

public java.util.stream.Stream<T> stream()

Always returns an empty stream.

Specified by:

stream in interface Option<T>

Returns:

Empty stream

equals

public boolean equals(Object other)

Always returns true as None is stateless comparing it to some other None is therefore always the same.

Overrides:

equals in class Object

Parameters:

other - The other object to compare to

hashCode

public int hashCode()

Always returns 0 as None is stateless and has no value.

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object