This demonstrates the Decorator pattern using functional programming

Camera.java

import java.awt.*;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.stream.Stream;

public class Camera {

    private Function<Color, Color> filter;

    public Camera(){
        setFilters();
    }

    public void setFilters(final Function<Color, Color>... filters) {
        // orElseGet(Function::identity) is the same as orElse(color -> color). This is to say return the color that was passed into the function
        this.filter = Stream.of(filters)
                            .reduce((filter, next) -> filter.compose(next))
                            .orElseGet(Function::identity);
    }

    public Color capture(final Color inputColor) {
        final Color processedColor = filter.apply(inputColor);
        // ... more processing of color...
        return processedColor;
    }

    public static void main(String[] args) {
        final Camera camera = new Camera();
        final Consumer<String> printCaptured = (filterInfo) -> System.out.println(String.format("with %s: %s", filterInfo, camera.capture(new Color(200, 100, 200))));

        printCaptured.accept("no filter");

        camera.setFilters(Color::brighter);
        printCaptured.accept("brighter filter");

        camera.setFilters(Color::darker);
        printCaptured.accept("darker filter");

        camera.setFilters(Color::brighter, Color::darker);
        printCaptured.accept("brighter & darker filter");


    }
}