Optional (stream-lite API Documentation)

java.lang.Object
- com.annimon.stream.Optional<T>

Type Parameters:
T - the type of the inner value
```
public class Optional<T>
extends java.lang.Object
```
A container object which may or may not contain a non-null value.

Method Summary

Methods
Modifier and Type	Method and Description
`static <T> Optional<T>`	`empty()` Returns an empty `Optional`.
`boolean`	`equals(java.lang.Object obj)`
`Optional<T>`	`filter(Predicate<? super T> predicate)` Performs filtering on inner value if it is present.
`<U> Optional<U>`	`flatMap(Function<? super T,Optional<U>> mapper)` Invokes mapping function with `Optional` result if value is present.
`T`	`get()` Returns an inner value if present, otherwise throws `NoSuchElementException`.
`int`	`hashCode()`
`void`	`ifPresent(Consumer<? super T> consumer)` Invokes consumer function with value if present.
`void`	`ifPresentOrElse(Consumer<? super T> consumer, java.lang.Runnable emptyAction)` If a value is present, performs the given action with the value, otherwise performs the given empty-based action.
`boolean`	`isPresent()` Checks value present.
`<U> Optional<U>`	`map(Function<? super T,? extends U> mapper)` Invokes the given mapping function on inner value if present.
`static <T> Optional<T>`	`of(T value)` Returns an `Optional` with the specified present non-null value.
`static <T> Optional<T>`	`ofNullable(T value)` Returns an `Optional` with the specified value, or empty `Optional` if value is null.
`T`	`or(T other)` Returns inner value if present, otherwise returns `other`.
`T`	`orGet(Supplier<? extends T> other)` Returns inner value if present, otherwise returns value produced by supplier function.
`<X extends java.lang.Throwable> T`	`orThrow(Supplier<? extends X> exc)` Returns inner value if present, otherwise throws the exception provided by supplier function.
`Stream<T>`	`stream()` Wraps a value into `Stream` if present, otherwise returns an empty `Stream`.
`java.lang.String`	`toString()`

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Method Detail
 - of
```
public static <T> Optional<T> of(T value)
```
 Returns an Optional with the specified present non-null value.
 
 Type Parameters:
 T - the type of value
 Parameters:
 value - the value to be present, must be non-null
 
 Returns:
 an Optional
 
 Throws:
 
 java.lang.NullPointerException - if value is null
 See Also:
 ofNullable(java.lang.Object)
 - ofNullable
```
public static <T> Optional<T> ofNullable(T value)
```
 Returns an Optional with the specified value, or empty Optional if value is null.
 
 Type Parameters:
 T - the type of value
 Parameters:
 value - the value which can be null
 
 Returns:
 an Optional
 See Also:
 of(java.lang.Object)
 - empty
```
public static <T> Optional<T> empty()
```
 Returns an empty Optional.
 
 Type Parameters:
 T - the type of value
 
 Returns:
 an Optional
 - get
```
public T get()
```
 Returns an inner value if present, otherwise throws NoSuchElementException.
 
 Returns:
 the inner value of Optional
 
 Throws:
 
 java.util.NoSuchElementException - if value is not present
 - isPresent
```
public boolean isPresent()
```
 Checks value present.
 
 Returns:
 true if a value present, false otherwise
 - ifPresent
```
public void ifPresent(Consumer<? super T> consumer)
```
 Invokes consumer function with value if present.
 
 Parameters:
 consumer - the consumer function
 - ifPresentOrElse
```
public void ifPresentOrElse(Consumer<? super T> consumer,
 java.lang.Runnable emptyAction)
```
 If a value is present, performs the given action with the value, otherwise performs the given empty-based action.
 
 Parameters:
 consumer - the consumer function to be executed, if a value is present
 emptyAction - the empty-based action to be performed, if no value is present
 
 Throws:
 
 java.lang.NullPointerException - if a value is present and the given consumer function is null, or no value is present and the given empty-based action is null.
 - filter
```
public Optional<T> filter(Predicate<? super T> predicate)
```
 Performs filtering on inner value if it is present.
 
 Parameters:
 predicate - a predicate function
 
 Returns:
 this Optional if the value is present and matches predicate, otherwise an empty Optional
 - map
```
public  Optional map(Function<? super T,? extends U> mapper)
```
 Invokes the given mapping function on inner value if present.
 
 Type Parameters:
 U - the type of result value
 Parameters:
 mapper - mapping function
 
 Returns:
 an Optional with transformed value if present, otherwise an empty Optional
 
 Throws:
 
 java.lang.NullPointerException - if value is present and mapper is null
 - flatMap
```
public  Optional flatMap(Function<? super T,Optional> mapper)
```
 Invokes mapping function with Optional result if value is present.
 
 Type Parameters:
 U - the type of result value
 Parameters:
 mapper - mapping function
 
 Returns:
 an Optional with transformed value if present, otherwise an empty Optional
 - stream
```
public Stream<T> stream()
```
 Wraps a value into Stream if present, otherwise returns an empty Stream.
 
 Returns:
 the optional value as a Stream
 - or
```
public T or(T other)
```
 Returns inner value if present, otherwise returns other.
 
 Parameters:
 other - the value to be returned if inner value is not present
 
 Returns:
 inner value if present, otherwise other
 - orGet
```
public T orGet(Supplier<? extends T> other)
```
 Returns inner value if present, otherwise returns value produced by supplier function.
 
 Parameters:
 other - supplier function that produces value if inner value is not present
 
 Returns:
 inner value if present, otherwise value produced by supplier function
 - orThrow
```
public <X extends java.lang.Throwable> T orThrow(Supplier<? extends X> exc)
 throws X extends java.lang.Throwable
```
 Returns inner value if present, otherwise throws the exception provided by supplier function.
 
 Type Parameters:
 X - the type of exception to be thrown
 Parameters:
 exc - supplier function that produces an exception to be thrown
 
 Returns:
 inner value if present
 
 Throws:
 
 X - if inner value is not present
 
 X extends java.lang.Throwable
 - equals
```
public boolean equals(java.lang.Object obj)
```
 Overrides:
 
 equals in class java.lang.Object
 - hashCode
```
public int hashCode()
```
 Overrides:
 
 hashCode in class java.lang.Object
 - toString
```
public java.lang.String toString()
```
 Overrides:
 
 toString in class java.lang.Object

Class Optional<T>

Method Summary

Methods inherited from class java.lang.Object

Method Detail

of

ofNullable

empty

get

isPresent

ifPresent

ifPresentOrElse

filter

map

flatMap

stream

or

orGet

orThrow

equals

hashCode

toString