Type Parameters:

T - see Function

R - see Function

All Superinterfaces:

Function<T,Optional<R>>

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
```
@FunctionalInterface
public interface OptionalFunction<T,R>
extends Function<T,Optional<R>>
```
Variation of Function that returns Optional instead of the raw value. OptionalFunction is typically obtained from ExceptionHandler.function(Function), in which case its return value is empty when the underlying Function throws an exception. See noexception tutorial.

See Also:

ExceptionHandler.function(Function), Function

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`Optional<R>`	`apply(T t)`	Variation of `Function.apply(Object)` that returns `Optional`.
`default Function<T,R>`	`orElse(R result)`	Converts this `OptionalFunction` to plain `Function` using default value.
`default Function<T,R>`	`orElseGet(Supplier<R> source)`	Converts this `OptionalFunction` to plain `Function` using fallback `Supplier`.

Methods inherited from interface java.util.function.Function
andThen, compose

- Method Detail
  - apply
```
Optional<R> apply(T t)
```
    Variation of Function.apply(Object) that returns Optional. If this OptionalFunction is obtained from ExceptionHandler.function(Function), the Optional will be empty only if the underlying Function throws. Otherwise the returned Optional just wraps the return value of underlying Function (possibly null).
    
    Specified by:
    
    apply in interface Function<T,R>
    
    Parameters:
    
    t - see Function.apply(Object)
    
    Returns:
    
    Optional typically wrapping return value of Function.apply(Object), or an empty Optional (typically signifying an exception)
    
    See Also:
    
    ExceptionHandler.function(Function), Function.apply(Object)
  - orElse
```
default Function<T,R> orElse(R result)
```
    Converts this OptionalFunction to plain Function using default value. The returned Function will unwrap present value from the Optional if possible, or return result if the Optional is empty.
    
    Parameters:
    
    result - default value to return instead of an empty Optional
    
    Returns:
    
    plain Function that either unwraps Optional or returns default value
    
    See Also:
    
    orElseGet(Supplier), Optional.orElse(Object)
  - orElseGet
```
default Function<T,R> orElseGet(Supplier<R> source)
```
    Converts this OptionalFunction to plain Function using fallback Supplier. The returned Function will unwrap present value from the Optional if possible, or fall back to calling source if the Optional is empty.
    
    Parameters:
    
    source - Supplier to query for fallback value when Optional is empty
    
    Returns:
    
    plain Function that either unwraps Optional or falls back to source
    
    See Also:
    
    orElse(Object), Optional.orElseGet(Supplier)

Interface OptionalFunction<T,​R>

Method Summary

Methods inherited from interface java.util.function.Function

Method Detail

apply

orElse

orElseGet

Interface OptionalFunction<T,R>