Options (Functional Extensions Library 4.5.1 API)

java.lang.Object
- io.atlassian.fugue.Options

```
public class Options
extends Object
```
Utility methods for working with options.

Since:

1.1

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static <A,B> Option<B>`	`ap(Option<A> oa, Option<Function<A,B>> of)` Applies an option of A to an option of a function with input type A and result type B and return an option of B.
`static <A> Iterable<Option<A>>`	`filterNone(Iterable<Option<A>> options)` Filter out undefined options.
`static <A> Option<A>`	`find(Iterable<Option<A>> options)` Find the first option that `isDefined`, or if there aren't any, then none.
`static <A> Iterable<A>`	`flatten(Iterable<Option<A>> options)` Flattens an `Iterable` of `options` into an iterable of the things, filtering out any nones.
`static <A,B> Function<Function<A,B>,Function<Option<A>,Option<B>>>`	`lift()` Returns a function that will lift a function that takes an A and returns a B into a function that takes an option of A and returns an option of B.
`static <A,B> Function<Option<A>,Option<B>>`	`lift(Function<A,B> f)` Lifts a function that takes an A and returns a B into a function that takes an option of A and returns an option of B.
`static <A> Predicate<Option<A>>`	`lift(Predicate<? super A> pred)` Lifts a predicate that takes an A into a predicate that takes an option of A.
`static <A,B,C> Function<BiFunction<A,B,C>,BiFunction<Option<A>,Option<B>,Option<C>>>`	`lift2()` Returns a function that will lift a function that takes an A and a B and returns a C into a function that takes an option of A and an option of B and returns an option of C.
`static <A,B,C> BiFunction<Option<A>,Option<B>,Option<C>>`	`lift2(BiFunction<A,B,C> f2)` Lifts a function that takes an A and a B and returns a C into a function that takes an option of A and an option of B and returns an option of C.
`static <A,B> Function<A,Option<B>>`	`nullSafe(Function<A,B> nullProducing)` Turn a null producing function into one that returns an option instead.
`static <A> Function<A,Option<A>>`	`toOption()` Function for wrapping values in a Some or None.
`static <AA,A extends AA> Option<AA>`	`upcast(Option<A> o)` Upcasts an `option` of type A to an option of its super type AA.

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

- Method Detail
 - find
```
public static <A> Option<A> find(Iterable<Option<A>> options)
```
 Find the first option that isDefined, or if there aren't any, then none.
 
 Type Parameters:
 
 A - the contained type
 
 Parameters:
 
 options - an Iterable of options to search through
 
 Returns:
 
 the first defined option, or none if there aren't any
 - upcast
```
public static <AA,A extends AA> Option<AA> upcast(Option<A> o)
```
 Upcasts an option of type A to an option of its super type AA.
 
 Type Parameters:
 
 AA - the super type of the contained type
 
 A - a A object.
 
 Parameters:
 
 o - the source option
 
 Returns:
 
 an option of the super type
 
 Since:
 
 2.0
 - lift
```
public static <A,B> Function<Option<A>,Option> lift(Function<A,B> f)
```
 Lifts a function that takes an A and returns a B into a function that takes an option of A and returns an option of B.
 
 Type Parameters:
 
 A - the input type of the original function
 
 B - the result type of the original function
 
 Parameters:
 
 f - the original function to be lifted, must not be null
 
 Returns:
 
 a function that takes an option of type A and returns an option of type B
 
 Since:
 
 2.0
 - lift
```
public static <A,B> Function<Function<A,B>,Function<Option<A>,Option>> lift()
```
 Returns a function that will lift a function that takes an A and returns a B into a function that takes an option of A and returns an option of B.
 
 Type Parameters:
 
 A - the input type of the function that can be lifted
 
 B - the result type of the function that can be lifted
 
 Returns:
 
 a function that can lift a function of input type A and result type B into Option
 
 Since:
 
 2.0
 - lift
```
public static <A> Predicate<Option<A>> lift(Predicate<? super A> pred)
```
 Lifts a predicate that takes an A into a predicate that takes an option of A.
 
 Type Parameters:
 
 A - the input type of the predicate
 
 Parameters:
 
 pred - the original predicate to be lifted, must not be null
 
 Returns:
 
 a predicate that takes an option of type A
 
 Since:
 
 2.2
 - ap
```
public static <A,B> Option ap(Option<A> oa,
 Option<Function<A,B>> of)
```
 Applies an option of A to an option of a function with input type A and result type B and return an option of B.
 
 Type Parameters:
 
 A - the input type of the function wrapped in the option 'of'
 
 B - the result type of the function wrapped in the option 'of'
 
 Parameters:
 
 oa - an option of the argument to the function
 
 of - an option of a function that takes an A and returns a B
 
 Returns:
 
 an option of B
 
 Since:
 
 2.0
 - lift2
```
public static <A,B,C> BiFunction<Option<A>,Option,Option<C>> lift2(BiFunction<A,B,C> f2)
```
 Lifts a function that takes an A and a B and returns a C into a function that takes an option of A and an option of B and returns an option of C.
 
 Type Parameters:
 
 A - the input type of the first argument of the original function
 
 B - the input type of the second argument of the original function
 
 C - the result type of the original function
 
 Parameters:
 
 f2 - the original function to be lifted
 
 Returns:
 
 a function that takes an option of type A and an option of B and returns an option of type C
 
 Since:
 
 2.0
 - lift2
```
public static <A,B,C> Function<BiFunction<A,B,C>,BiFunction<Option<A>,Option,Option<C>>> lift2()
```
 Returns a function that will lift a function that takes an A and a B and returns a C into a function that takes an option of A and an option of B and returns an option of C.
 
 Type Parameters:
 
 A - the input type of the first argument of the function that can be lifted
 
 B - the input type of the second argument of the function that can be lifted
 
 C - the result type of the function that can be lifted
 
 Returns:
 
 a function that can lift a function of input type A and B and result type C into Option
 
 Since:
 
 2.0
 - filterNone
```
public static <A> Iterable<Option<A>> filterNone(Iterable<Option<A>> options)
```
 Filter out undefined options.
 
 Type Parameters:
 
 A - the contained type
 
 Parameters:
 
 options - many options that may or may not be defined
 
 Returns:
 
 the filtered options
 - flatten
```
public static <A> Iterable<A> flatten(Iterable<Option<A>> options)
```
 Flattens an Iterable of options into an iterable of the things, filtering out any nones.
 
 Type Parameters:
 
 A - the contained type
 
 Parameters:
 
 options - the iterable of options
 
 Returns:
 
 an Iterable of the contained type
 - toOption
```
public static <A> Function<A,Option<A>> toOption()
```
 Function for wrapping values in a Some or None.
 
 Type Parameters:
 
 A - the contained type
 
 Returns:
 
 a Function to wrap values
 
 Since:
 
 3.0
 - nullSafe
```
public static <A,B> Function<A,Option> nullSafe(Function<A,B> nullProducing)
```
 Turn a null producing function into one that returns an option instead.
 
 Type Parameters:
 
 A - input type to the function.
 
 B - output type of the function.
 
 Parameters:
 
 nullProducing - the function that may return null
 
 Returns:
 
 a function that turns nulls into None, and wraps non-null values in Some.
 
 Since:
 
 3.0

Class Options

Method Summary

Methods inherited from class java.lang.Object

Method Detail

find

upcast

lift

lift

lift

ap

lift2

lift2

filterNone

flatten

toOption

nullSafe