OptionalBoolean

OptionalBoolean.java

public enum OptionalBoolean
{
    TRUE(Boolean.TRUE),
    FALSE(Boolean.FALSE),
    EMPTY(null);

    private final Boolean value;

    private OptionalBoolean(Boolean value)
    {
        this.value = value;
    }

    public static OptionalBoolean ofNullable(Boolean value)
    {
        return value == null ? EMPTY : of(value.booleanValue());
    }

    public static OptionalBoolean of(boolean value)
    {
        return value ? TRUE : FALSE;
    }

    public <T> Optional<T> mapTrue(Supplier<T> mapper)
    {
        Objects.requireNonNull(mapper);
        if (this == TRUE)
            return Optional.ofNullable(mapper.get());
        else
            return Optional.empty();
    }

    public <T> Optional<T> mapFalse(Supplier<T> mapper)
    {
        Objects.requireNonNull(mapper);
        if (this == FALSE)
            return Optional.ofNullable(mapper.get());
        else
            return Optional.empty();
    }

    public OptionalBoolean ifTrue(Runnable runnable)
    {
        if (this == TRUE)
            runnable.run();
        return this;
    }

    public OptionalBoolean ifFalse(Runnable runnable)
    {
        if (this == FALSE)
            runnable.run();
        return this;
    }

    public OptionalBoolean ifAbsent(Runnable runnable)
    {
        if (this == EMPTY)
            runnable.run();
        return this;
    }

    public boolean orElse(boolean fallback)
    {
        return this != EMPTY ? value : fallback;
    }

    public boolean orElseGet(BooleanSupplier fallbackSupplier)
    {
        return this != EMPTY ? value : fallbackSupplier.getAsBoolean();
    }

    public <X extends Throwable> boolean orElseThrow(Supplier<? extends X> exceptionSupplier) throws X
    {
        if (this != EMPTY)
            return value;
        else
            throw exceptionSupplier.get();
    }
}