Opt (jaci-utils 0.4.0 API)

java.lang.Object
- com.github.ykrasik.jaci.util.opt.Opt<T>

Type Parameters:

T - Argument type.

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable<T>
```
public abstract class Opt<T>
extends java.lang.Object
implements java.lang.Iterable<T>, java.io.Serializable
```
Just like Java 8's or Guava's Optional. Uses a different name to avoid name confusion.

See Also:

Serialized Form

Constructor Summary

Constructors
Modifier Constructor and Description

protected Opt()

Constructors
Modifier	Constructor and Description
`protected`	`Opt()`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`static <T> Opt<T>`	`absent()`
`abstract boolean`	`exists(Pred<? super T> predicate)`
`abstract Opt<T>`	`filter(Pred<? super T> predicate)`
`abstract <V> Opt<V>`	`flatMap(Func<? super T,Opt<V>> function)`
`static <T> Opt<T>`	`fromCollection(java.util.Collection<T> col)` Create an `Opt` instance out of a `Collection`.
`abstract T`	`get()`
`abstract T`	`getOrElse(T defaultValue)`
`abstract T`	`getOrElseNull()`
`abstract boolean`	`isPresent()`
`java.util.Iterator<T>`	`iterator()`
`abstract <V> Opt<V>`	`map(Func<? super T,V> function)`
`static <T> Opt<T>`	`of(T value)`
`static <T> Opt<T>`	`ofNullable(T value)`
`abstract Opt<T>`	`orElse(Opt<? extends T> alternative)`
`abstract java.util.List<T>`	`toList()`
`abstract <K> java.util.Map<K,T>`	`toMap(K key)`
`abstract java.util.Set<T>`	`toSet()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.lang.Iterable
forEach, spliterator

- Constructor Detail
  - Opt
```
protected Opt()
```
- Method Detail
  - absent
```
public static <T> Opt<T> absent()
```
    Type Parameters:
    
    T - Absent value type.
    
    Returns:
    
    An empty Opt instance that contains no value.
  - of
```
public static <T> Opt<T> of(T value)
```
    Type Parameters:
    
    T - Value type.
    
    Parameters:
    
    value - Value to wrap in an Opt, must be non-null.
    
    Returns:
    
    A non-empty Opt instance with the given value.
    
    Throws:
    
    java.lang.NullPointerException - If value is null.
  - ofNullable
```
public static <T> Opt<T> ofNullable(T value)
```
    Type Parameters:
    
    T - Value type.
    
    Parameters:
    
    value - Possibly nullable value.
    
    Returns:
    
    A non-empty Opt if the value is non-null, or an empty one otherwise.
  - fromCollection
```
public static <T> Opt<T> fromCollection(java.util.Collection<T> col)
```
    Create an Opt instance out of a Collection. The collection's size may not be greater than 1. Returns a non-empty Opt with the collection's only element if the collection is non-empty, or an empty Opt otherwise.
    
    Type Parameters:
    
    T - Collection type.
    
    Parameters:
    
    col - Collection to extract an Opt out of. The collection's size may not be greater than 1.
    
    Returns:
    
    A non-empty Opt if the Collection has a single element, or an empty one otherwise.
    
    Throws:
    
    java.lang.IllegalArgumentException - If the collection's size is greater than 1.
  - isPresent
```
public abstract boolean isPresent()
```
    Returns:
    
    true if this Opt contains a value, otherwise false.
  - get
```
public abstract T get()
```
    Returns:
    
    This Opt's non-null value.
    
    Throws:
    
    java.util.NoSuchElementException - If this Opt is empty.
  - getOrElseNull
```
public abstract T getOrElseNull()
```
    Returns:
    
    This Opt's value if this Opt is non-empty, or null otherwise.
  - getOrElse
```
public abstract T getOrElse(T defaultValue)
```
    Parameters:
    
    defaultValue - Default value to return if this Opt is empty.
    
    Returns:
    
    This Opt's value if this Opt is non-empty, or defaultValue otherwise.
  - orElse
```
public abstract Opt<T> orElse(Opt<? extends T> alternative)
```
    Parameters:
    
    alternative - Alternative Opt to return if this Opt is empty.
    
    Returns:
    
    This Opt if it is non-empty, or the alternative Opt otherwise.
  - map
```
public abstract <V> Opt<V> map(Func<? super T,V> function)
```
    Type Parameters:
    
    V - Returned Opt type.
    
    Parameters:
    
    function - Function to apply to this Opt's value, if this Opt is non-empty. May return null, in which case an empty Opt will be returned.
    
    Returns:
    
    An Opt containing the result of applying function to this Opt's value if this Opt is non-empty, or an empty Opt otherwise.
  - flatMap
```
public abstract <V> Opt<V> flatMap(Func<? super T,Opt<V>> function)
```
    Type Parameters:
    
    V - Returned Opt type.
    
    Parameters:
    
    function - Function to apply to this Opt's value, if this Opt is non-empty. Different from map(Func) in that function must return an Opt.
    
    Returns:
    
    The Opt result of applying function to this Opt's value if this Opt is non-empty, or an empty Opt otherwise.
  - exists
```
public abstract boolean exists(Pred<? super T> predicate)
```
    Parameters:
    
    predicate - Predicate to apply to this Opt's value if this Opt is non-empty.
    
    Returns:
    
    true if this Opt is non-empty and applying the predicate to this Opt's value returns true, otherwise returns false.
  - filter
```
public abstract Opt<T> filter(Pred<? super T> predicate)
```
    Parameters:
    
    predicate - Predicate to apply to this Opt's value if this Opt is non-empty.
    
    Returns:
    
    This Opt if this Opt is non-empty and applying the predicate to it returns true, otherwise returns an empty Opt.
  - toList
```
public abstract java.util.List<T> toList()
```
    Returns:
    
    A singleton List containing this Opt's value if this Opt is non-empty, or an empty List otherwise.
  - toSet
```
public abstract java.util.Set<T> toSet()
```
    Returns:
    
    A singleton Set containing this Opt's value if this Opt is non-empty, or an empty Set otherwise.
  - toMap
```
public abstract <K> java.util.Map<K,T> toMap(K key)
```
    Type Parameters:
    
    K - Key type.
    
    Parameters:
    
    key - Key to use for mapping if this Opt is non-empty.
    
    Returns:
    
    A singleton Map containing a single mapping from the given key to this Opt's value if this Opt is non-empty, or an empty Map otherwise.
  - iterator
```
public final java.util.Iterator<T> iterator()
```
    Specified by:
    
    iterator in interface java.lang.Iterable<T>

Class Opt<T>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.lang.Iterable

Constructor Detail

Opt

Method Detail

absent

of

ofNullable

fromCollection

isPresent

get

getOrElseNull

getOrElse

orElse

map

flatMap

exists

filter

toList

toSet

toMap

iterator