org.n52.janmayen

Class Optionals

java.lang.Object

org.n52.janmayen.Optionals

public final class Optionals
extends Object

Utility functions for Optional.

Method Summary

Modifier and Type	Method and Description
static boolean	any(Iterable<Optional<?>> optionals) Checks if any of the optionals is present.
static boolean	any(Optional<?>... optionals) Checks if any of the optionals is present.
static boolean	any(Stream<Optional<?>> optionals) Checks if any of the optionals is present.
static <U> Optional<U>	ifPresentOrElse(Optional<U> optional, Consumer<U> consumer, Runnable ifNotPresent) Feeds {code optional}'s value to consumer if it is present or else runs ifNotPresent.
static <U,T> Optional<U>	mapOrElse(Optional<T> optional, Function<? super T,? extends U> mapper, Runnable ifNotPresent) Maps the optional using mapper if it is present or runs ifNotPresent.
static <U extends Comparable<? super U>> Comparator<Optional<U>>	nullsFirst() Creates a comparator to sort by the optional's value, nulls first.
static <U> Comparator<Optional<U>>	nullsFirst(Comparator<? super U> comparator) Creates a comparator wrapping comparator to sort by the optional's value, nulls first.
static <U extends Comparable<? super U>> Comparator<Optional<U>>	nullsLast() Creates a comparator to sort by the optional's value, nulls last.
static <U> Comparator<Optional<U>>	nullsLast(Comparator<? super U> comparator) Creates a comparator wrapping comparator to sort by the optional's value, nulls last.
static <U> Optional<U>	or(Optional<U>... optionals) Gets the first value of the first optional that is present.
static <U> Optional<U>	or(Optional<U> a, Optional<U> b) Gets the value of a if it is present or else the value of b.
static <U> Optional<U>	or(Optional<U> a, Supplier<Optional<U>> b) Gets the value of a if it is present or else the value of b.
static <U> Optional<U>	or(Stream<Supplier<Optional<U>>> optionals) Gets the first value of the first optional that is present.
static <U> Optional<U>	or(Supplier<Optional<U>>... optionals) Gets the first value of the first optional that is present.
static <U> U	orElseNull(Optional<U> optional) Gets the value of optional if it is present, null otherwise.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

any

public static boolean any(Optional<?>... optionals)

Checks if any of the optionals is present.

Parameters:

optionals - the optionals

Returns:

if at least one is present

any

public static boolean any(Iterable<Optional<?>> optionals)

Checks if any of the optionals is present.

Parameters:

optionals - the optionals

Returns:

if at least one is present

any

public static boolean any(Stream<Optional<?>> optionals)

Checks if any of the optionals is present.

Parameters:

optionals - the optionals

Returns:

if at least one is present

nullsLast

public static <U> Comparator<Optional<U>> nullsLast(Comparator<? super U> comparator)

Creates a comparator wrapping comparator to sort by the optional's value, nulls last.

Type Parameters:

U - the optional's type

Parameters:

comparator - the comparator

Returns:

the new comparator

nullsLast

public static <U extends Comparable<? super U>> Comparator<Optional<U>> nullsLast()

Creates a comparator to sort by the optional's value, nulls last.

Type Parameters:

U - the optional's type

Returns:

the new comparator

nullsFirst

public static <U> Comparator<Optional<U>> nullsFirst(Comparator<? super U> comparator)

Creates a comparator wrapping comparator to sort by the optional's value, nulls first.

Type Parameters:

U - the optional's type

Parameters:

comparator - the comparator

Returns:

the new comparator

nullsFirst

public static <U extends Comparable<? super U>> Comparator<Optional<U>> nullsFirst()

Creates a comparator to sort by the optional's value, nulls first.

Type Parameters:

U - the optional's type

Returns:

the new comparator

orElseNull

public static <U> U orElseNull(Optional<U> optional)

Gets the value of optional if it is present, null otherwise.

Type Parameters:

U - the optional's type

Parameters:

optional - the optional

Returns:

the optional's value or null

ifPresentOrElse

public static <U> Optional<U> ifPresentOrElse(Optional<U> optional,
                                              Consumer<U> consumer,
                                              Runnable ifNotPresent)

Feeds {code optional}'s value to consumer if it is present or else runs ifNotPresent.

Type Parameters:

U - the optional's type

Parameters:

optional - the optional

consumer - the consumer

ifNotPresent - the runnable

Returns:

the optional

mapOrElse

public static <U,T> Optional<U> mapOrElse(Optional<T> optional,
                                          Function<? super T,? extends U> mapper,
                                          Runnable ifNotPresent)

Maps the optional using mapper if it is present or runs ifNotPresent.

Type Parameters:

T - the resulting optional's type

U - the optional's type

Parameters:

optional - the optinal

mapper - the mapper

ifNotPresent - the runnable

Returns:

the new optional

or

public static <U> Optional<U> or(Optional<U> a,
                                 Supplier<Optional<U>> b)

Gets the value of a if it is present or else the value of b.

Type Parameters:

U - the optional's type

Parameters:

a - the first optional

b - a supplier for the second optional

Returns:

the value

or

public static <U> Optional<U> or(Optional<U> a,
                                 Optional<U> b)

Gets the value of a if it is present or else the value of b.

Type Parameters:

U - the optional's type

Parameters:

a - the first optional

b - a the second optional

Returns:

the value

or

@SafeVarargs
public static <U> Optional<U> or(Optional<U>... optionals)

Gets the first value of the first optional that is present.

Type Parameters:

U - the optional's type

Parameters:

optionals - the optionals

Returns:

the first present value

or

@SafeVarargs
public static <U> Optional<U> or(Supplier<Optional<U>>... optionals)

Gets the first value of the first optional that is present.

Type Parameters:

U - the optional's type

Parameters:

optionals - the optionals

Returns:

the first present value

or

public static <U> Optional<U> or(Stream<Supplier<Optional<U>>> optionals)

Gets the first value of the first optional that is present.

Type Parameters:

U - the optional's type

Parameters:

optionals - the optionals

Returns:

the first present value