import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.function.Function;

class Teddy {
    private final String name;

    Teddy(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return String.format("{ Teddy: %s }", this.name);
    }
}

class Box<T> {
    private T value;

    Box() {
        this.value = null;
    }

    Box(T value) {
        this.value = value;
    }

    public void add(T thing) {
        if (this.value != null) {
            System.out.println("No empty space for you!");
        } else {
            this.value = thing;
        }
    }

    public static <T> Box<T> of(T thing){
        return new Box<>(thing);
    }

    public static <T extends Number> Box<T> ofNumber(T thing){
        return new Box<>(thing);
    }

    @Override
    public String toString() {
        if (this.value == (null)) {
            return "[]";
        }
        return String.format("[%s]", this.value);
    }

    public <R> Box<R> manipulate(Function<T,R> transform){
        R result = transform.apply(this.value);
        return new Box<>(result);
    }
}

public class GenericsBruhh {
    public static void main(String[] args) {
        Box<Integer> integerBox = Box.ofNumber(1);
        Function<Integer, Double> incOnePointOne = (v) -> v + 1.1;
        Box<Double> doubleBox = integerBox.manipulate(incOnePointOne);
        System.out.println(new Box<>(doubleBox));
    }
}