Package org.anchoranalysis.core.functional

Class OptionalFactory

Object

OptionalFactory

public class OptionalFactory
extends Object

Utility functions to create Optional from flags.

See OptionalUtilities for utility functions for already-instantiated Optionals.

Author:

Owen Feehan

Method Summary

Modifier and Type	Method	Description
static <T> Optional<T>	create(boolean flag, Supplier<T> supplier)	Creates only if a boolean flag is true, otherwise returns Optional.empty().
static <T> Optional<T>	create(boolean flag, T value)	Creates only if a boolean flag is true, otherwise returns Optional.empty().
static Optional<String>	create(String string)	Creates Optional.empty() for an empty string, or otherwise Optional.of().
static <T, E extends Exception> Optional<T>	createChecked(boolean flag, CheckedSupplier<T,E> supplier)	Like create(boolean, T) but accepts a supplier that throws a checked/exception.
static <T> Optional<T>	createFlat(boolean flag, Supplier<Optional<T>> valueIfFlagTrue)	Creates an Optional from a boolean flag and a supplier that returns an Optional.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

create

public static <T> Optional<T> create(boolean flag,
 T value)

Creates only if a boolean flag is true, otherwise returns Optional.empty().

Type Parameters:

T - type of optional

Parameters:

flag - boolean flag.

value - a value used only if flag is true.

Returns:

an optional that is defined or empty depending on the flag.

create

public static <T> Optional<T> create(boolean flag,
 Supplier<T> supplier)

Creates only if a boolean flag is true, otherwise returns Optional.empty().

Type Parameters:

T - type of optional

Parameters:

flag - boolean flag.

supplier - a function to create a value T only called if flag is true.

Returns:

an optional that is defined or empty depending on the flag.

createChecked

public static <T,
E extends Exception> Optional<T> createChecked(boolean flag,
 CheckedSupplier<T,E> supplier)
                                                          throws E

Like create(boolean, T) but accepts a supplier that throws a checked/exception.

Type Parameters:

T - type of optional

E - the checked exception

Parameters:

flag - boolean flag

supplier - a function to create a value T only called if flag is true

Returns:

an optional that is defined or empty depending on the flag

Throws:

E - if supplier throws it

create

public static Optional<String> create(String string)

Creates Optional.empty() for an empty string, or otherwise Optional.of().

Parameters:

string - the string (possibly empty or null).

Returns:

the optional.

createFlat

public static <T> Optional<T> createFlat(boolean flag,
 Supplier<Optional<T>> valueIfFlagTrue)

Creates an Optional from a boolean flag and a supplier that returns an Optional.

Type Parameters:

T - type in optional.

Parameters:

flag - iff true an populated optional is returned, otherwise Optional.empty().

valueIfFlagTrue - used to generate a positive value.

Returns:

a filled or empty optional depending on flag.