Possible

Type Parameters:

T - the type of the possible value

All Known Subinterfaces:

Fulfillable<T>

All Known Implementing Classes:

AbstractDynamicPossible, Holder, Reference
```
public interface Possible<T>
```
A possible value. A value might be present, but it may not be. This interface provides basically the same API as Optional, but as an interface instead of a class. Other implementations are provided in this package, including ones that allow present null values and ones that are mutable.

Nested Class Summary

Nested Classes
Modifier and Type Interface and Description

static interface Possible.Visitor<T,R>
A visitor of possible values.

Nested Classes
Modifier and Type	Interface and Description
`static interface`	`Possible.Visitor<T,R>` A visitor of possible values.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`Set<T>`	`asSet()` Returns a view of this possible value as a set.
`Possible<T>`	`filter(Predicate<? super T> predicate)` Filters the current value per the specified predicate.
`<U> Possible<U>`	`flatMap(Function<? super T,? extends Possible<U>> function)`
`T`	`get()` Gets the contained value if present.
`void`	`ifPresent(Consumer<? super T> consumer)`
`boolean`	`isPresent()` Returns true if a value is present.
`<U> Possible<U>`	`map(Function<? super T,? extends U> function)` Returns the current possible value, transformed by the specified function, if present.
`static <T> Possible<T>`	`notNull(Possible<T> possible)` Converts a possible `null` value to an optional one.
`static <T> List<T>`	`nullIfNotPresent(Collection<? extends Possible<? extends T>> possibles)` Returns a list of the values, `null` if no value is present, from the specified collection of possible values.
`Possible<T>`	`or(Possible<T> alternate)` Returns the current possible value if present or the specified value if not.
`T`	`orElse(T alternate)` Gets the contained value if present or the specified value if not.
`T`	`orElseGet(Supplier<? extends T> supplier)`
`<X extends Throwable> T`	`orElseThrow(Supplier<? extends X> throwableSupplier)` Gets the contained value or gets an exception from the specified source and throws it
`static <T> List<T>`	`presentOnly(Collection<? extends Possible<? extends T>> possibles)` Returns a list of the present values from the specified collection of possible values.
`static <T> Possible<T>`	`snapshot(Possible<? extends T> possible)` Captures the current possible value into a new immutable possible value.
`<R> R`	`visit(Possible.Visitor<? super T,R> visitor)` Invokes the appropriate method on the specified visitor.

- Method Detail
 - isPresent
```
boolean isPresent()
```
 Returns true if a value is present.
 
 Returns:
 
 true if a value is present; false otherwise.
 - or
```
Possible<T> or(Possible<T> alternate)
```
 Returns the current possible value if present or the specified value if not.
 
 Parameters:
 
 alternate - an alternate value
 
 Returns:
 
 returns the current possible value if present or the alternate if not
 - map
```
 Possible map(Function<? super T,? extends U> function)
```
 Returns the current possible value, transformed by the specified function, if present.
 
 Parameters:
 
 function - the function used to transform the value
 
 Returns:
 
 returns the current value, transformed by the specified function, if present; otherwise returns a possible value that is absent
 - flatMap
```
 Possible flatMap(Function<? super T,? extends Possible> function)
```
 - filter
```
Possible<T> filter(Predicate<? super T> predicate)
```
 Filters the current value per the specified predicate. If a value is present and it matches the specified predicate then it is returned. Otherwise a possible value that is absent is returned.
 
 Parameters:
 
 predicate - the predicated used to test the value
 
 Returns:
 
 returns the current value if present and it matches the specified predicate; otherwise returns a possible value that is absent
 - get
```
T get()
```
 Gets the contained value if present.
 
 Returns:
 
 the contained value
 
 Throws:
 
 NoSuchElementException - if a value is not present
 - orElse
```
T orElse(T alternate)
```
 Gets the contained value if present or the specified value if not.
 
 Parameters:
 
 alternate - the alternate value
 
 Returns:
 
 the contained value if present or the alternate if not
 - orElseGet
```
T orElseGet(Supplier<? extends T> supplier)
```
 - orElseThrow
```
<X extends Throwable> T orElseThrow(Supplier<? extends X> throwableSupplier)
 throws X extends Throwable
```
 Gets the contained value or gets an exception from the specified source and throws it
 
 Parameters:
 
 throwableSupplier - a supplier of the exception to throw if a value is not present
 
 Returns:
 
 the contained value
 
 Throws:
 
 X - if a value is not present
 
 X extends Throwable
 - ifPresent
```
void ifPresent(Consumer<? super T> consumer)
```
 - asSet
```
Set<T> asSet()
```
 Returns a view of this possible value as a set. If a value is present, a singleton set with that value is returned. Otherwise, an empty set is returned.
 
 Returns:
 
 a singleton set with the contained value, if present; an empty set otherwise
 - visit
```
<R> R visit(Possible.Visitor<? super T,R> visitor)
```
 Invokes the appropriate method on the specified visitor. Returns the value that the visitor produces.
 
 Parameters:
 
 visitor - a visitor
 
 Returns:
 
 the value returned by the visitor
 - notNull
```
static <T> Possible<T> notNull(Possible<T> possible)
```
 Converts a possible null value to an optional one. If the given possible value is present but null, an absent value is returned.
 
 Parameters:
 
 possible - a possible value
 
 Returns:
 
 the possible value, but with null values treated as absent
 - presentOnly
```
static <T> List<T> presentOnly(Collection<? extends Possible<? extends T>> possibles)
```
 Returns a list of the present values from the specified collection of possible values. Possible values where no value is present are excluded. So the resulting list will have fewer elements than the specified collection in the event that not all values are present. The order of items in the list matches the iteration order of the specified collection. The returned list is a snapshot of the of the values present at the time this method is executed. If any of the input values are mutable and later become present or absent, that will never be reflected in the returned list.
 
 Parameters:
 
 possibles - a collection of possible values
 
 Returns:
 
 a list of present values
 - nullIfNotPresent
```
static <T> List<T> nullIfNotPresent(Collection<? extends Possible<? extends T>> possibles)
```
 Returns a list of the values, null if no value is present, from the specified collection of possible values. The resulting list will always have exactly the same number of elements as the specified collection, even if not all values are present. The order of items in the list matches the iteration order of the specified collection. The returned list is a snapshot of the of the values present at the time this method is executed. If any of the input values are mutable and later become present or absent, that will never be reflected in the returned list.
 
 Parameters:
 
 possibles - a collection of possible values
 
 Returns:
 
 a list of values extracted from the collection, null for objects where a value was not present
 - snapshot
```
static <T> Possible<T> snapshot(Possible<? extends T> possible)
```
 Captures the current possible value into a new immutable possible value. The returned object is an immutable copy of the specified value. If the specified object is mutable and later changes, those changes will not be reflected in the returned snapshot.
 
 Parameters:
 
 possible - a possible value
 
 Returns:
 
 an immutable snapshot of the possible value

Interface Possible<T>

Nested Class Summary

Method Summary

Method Detail

isPresent

or

map

flatMap

filter

get

orElse

orElseGet

orElseThrow

ifPresent

asSet

visit

notNull

presentOnly

nullIfNotPresent

snapshot