org.dmfs.optional

Interface Optional<T>

Type Parameters:

T - the type of the value.

All Known Implementing Classes:

Absent, First, Mapped, NullSafe, Present

public interface Optional<T>

An optional value. In contrast to Java's Optional this an interface, so custom implementations can be developed.

Method Summary

Modifier and Type	Method and Description
boolean	isPresent() Returns whether the optional value is present.
T	value() Returns the optional value.
T	value(T defaultValue) Returns the optional value or the given default value if the optional value is not present.

Method Detail

isPresent

boolean isPresent()

Returns whether the optional value is present.

Returns:

true if the value is present, false otherwise.

value

T value(T defaultValue)

Returns the optional value or the given default value if the optional value is not present.

Parameters:

defaultValue - The value to return if the optional value is not present.

Returns:

The optional value or the default value.

value

T value()
 throws java.util.NoSuchElementException

Returns the optional value.

Returns:

The value.

Throws:

java.util.NoSuchElementException - if the optional value is not present.