OptionalConsumerMain.java

import java.util.Optional;
import java.util.function.Consumer;

public class OptionalConsumerMain {

	public static void main(String[] args) {
		Optional<String> o = Optional.ofNullable(null);
		OptionalConsumer.of(o)
				.ifPresent(s -> System.out.println("isPresent " + s))
				.ifNotPresent(() -> System.out.println("! isPresent"));
	}

	static class OptionalConsumer<T> {
		private Optional<T> optional;

		private OptionalConsumer(Optional<T> optional) {
			this.optional = optional;
		}

		public static <T> OptionalConsumer<T> of(Optional<T> optional) {
			return new OptionalConsumer<>(optional);
		}

		public OptionalConsumer<T> ifPresent(Consumer<T> c) {
			optional.ifPresent(c);
			return this;
		}
		// did not like to use Runnable but I could not find any other alternative
		public OptionalConsumer<T> ifNotPresent(Runnable r) {
			if (!optional.isPresent())
				r.run();
			return this;
		}
	}
}