Type Parameters:

R - see DoubleFunction

All Superinterfaces:

DoubleFunction<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 OptionalDoubleFunction<R>
extends DoubleFunction<Optional<R>>
```
Variation of DoubleFunction that returns Optional instead of the raw value. OptionalDoubleFunction is typically obtained from ExceptionHandler.fromDoubleFunction(DoubleFunction), in which case its return value is empty when the underlying DoubleFunction throws an exception. See noexception tutorial.

See Also:

ExceptionHandler.fromDoubleFunction(DoubleFunction), DoubleFunction

Method Summary

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

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

Interface OptionalDoubleFunction<R>

Method Summary

Method Detail

apply

orElse

orElseGet