chore: create clean task branch

src/shoes/App.java

-package shoes;
-
-public class App {
-	public static void main(String[] args) throws BoxException {
-		Sneakers sneakers = new Sneakers("Blue Sneakers", 42.5);
-		Sneakers sneakers2 = new Sneakers("White Sneakers", 44.0);
-		Boots boots = new Boots("Brown Boots", 39.0);
-		Boots boots2 = new Boots("Black Boots", 37.5);
-
-		ShoeBox<Boots> sb1 = new ShoeBox<>();
-		ShoeBox<Sneakers> sb2 = new ShoeBox<>();
-		ShoeBox<Boots> sb3 = new ShoeBox<>();
-		ShoeBox<Sneakers> sb4 = new ShoeBox<>();
-		
-		sb1.putObjectInBox(boots);
-		sb2.putObjectInBox(sneakers);
-		sb3.putObjectInBox(boots2);
-		sb4.putObjectInBox(sneakers2);
-		
-		System.out.println(sb1);
-		System.out.println(sb2);
-		System.out.println("\n_____________________________________________\n");
-		
-		// task d)
-		System.out.println("Create shelf with x=3 y=5");
-		Shelf shelf = new Shelf(3,5);
-		
-		System.out.println("Leeres Regal:\n"+shelf);
-		
-		//Adding boxes to shelf
-		System.out.println("Add sb1 to 0/4");
-		shelf.addBox(0,4,sb1);
-		System.out.println("Add sb2 to 2/2");
-		shelf.addBox(2,2,sb2);
-		System.out.println("Add sb3 to 0/1");
-		shelf.addBox(0,1,sb3);
-		System.out.println("Add sb4 to 2/1");
-		shelf.addBox(2,1,sb4);
-		
-		System.out.println("\nContents of shelf:");
-		System.out.println(shelf);
-
-		//shelf.addBox(42, 32, sb1);  //IndexOutOfBoundsException
-		//System.out.println("Add sb2 to 2/2 to throw an Exception");
-		//shelf.addBox(2,2,sb2); //Exception
-		
-		//Removing boxes from shelf
-		System.out.println("Remove Box from 2/2");
-		shelf.removeBox(2, 2);
-
-		//shelf.removeBox(3, 5); //IndexOutOfBoundsException
-		//System.out.println("Remove Box from 2/2 to throw an Exception");
-		//shelf.removeBox(2, 2);  //Exception
-		
-		System.out.println("\nContents of shelf after removing:");
-		System.out.println(shelf);
-	}
-}

src/shoes/Boots.java

-package shoes;
-
-public class Boots extends Shoes {
-	public Boots(String name, double size) {
-		super(name, size);
-	}
-}

src/shoes/Box.java

-package shoes;
-
-public abstract class Box<T> {
-	private T content;
-
-	public Box() {
-		super();
-	}
-
-	public Box(T content) {
-		this.content = content;
-	}
-
-	public void putObjectInBox(T obj) throws BoxException {
-		if (content == null) {
-			content = obj;
-		} else {
-			throw new BoxException("Box is full!");
-		}
-	}
-
-	public T removeObjectInBox() {
-		T temp = content;
-		content = null;
-		return temp;
-	}
-
-	public T getObjectInBox() {
-		return content;
-	}
-
-	@Override
-	public String toString() {
-		return "[" + content + "]";
-	}
-}
\ No newline at end of file

src/shoes/BoxException.java

-package shoes;
-
-public class BoxException extends Exception {
-	public BoxException(String msg) {
-		super(msg);
-	}
-}

src/shoes/Shelf.java

-package shoes;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public class Shelf {
-	private ArrayList<ArrayList<ShoeBox<? extends Shoes>>> shelf;
-	private int height;
-	private int width;
-
-	public Shelf(int height, int width) {
-		this.height = height;
-		this.width = width;
-		shelf = new ArrayList<>();
-		for (int i = 0; i < height; i++) {
-			shelf.add(new ArrayList<ShoeBox<? extends Shoes>>());
-			for (int j = 0; j < width; j++) {
-				shelf.get(i).add(null); // add empty slots
-			}
-		}
-	}
-
-	public void addBox(int x, int y, ShoeBox<? extends Shoes> box) throws BoxException {
-		if (x < 0 || y < 0 || x >= this.height || y >= this.width)
-			throw new IndexOutOfBoundsException("There is no such place in the shelf!");
-		if (shelf.get(x).get(y) != null)
-			throw new BoxException("There is already a different box in " + x + "/" + y + "!");
-		shelf.get(x).set(y, box);
-	}
-
-	public void removeBox(int x, int y) throws BoxException {
-		if (x < 0 || y < 0 || x >= this.height || y >= this.width)
-			throw new IndexOutOfBoundsException("There is no such place in the shelf!");
-		if (shelf.get(x).get(y) == null)
-			throw new BoxException("No item to remove in " + x + "/" + y + "!");
-		shelf.get(x).set(y, null);
-	}
-
-	public ShoeBox<? extends Shoes> get(int x, int y) {
-		return shelf.get(x).get(y);
-	}
-
-	@Override
-	public String toString() {
-		StringBuilder sb = new StringBuilder();
-		for (List<ShoeBox<? extends Shoes>> shelfY : shelf) {
-			for (ShoeBox<? extends Shoes> box : shelfY) {
-				sb.append("|" + (box == null ? "----free----" : box.toString()) + "|");
-			}
-			sb.append('\n');
-
-		}
-		return sb.toString();
-	}
-}

src/shoes/ShoeBox.java

-package shoes;
-
-public class ShoeBox<T extends Shoes> extends Box<T> {
-	public ShoeBox() {
-		super();
-	}
-
-	public ShoeBox(T content) {
-		super(content);
-	}
-}

src/shoes/Shoes.java

-package shoes;
-
-public abstract class Shoes {
-	private String name;
-	private double size;	
-
-	public Shoes (String name, double size) {
-		this.name = name;
-		this.size = size;
-	}
-
-	@Override
-	public String toString() {
-		return "{" + name + ", " + size + "}";
-	}
-}

src/shoes/Sneakers.java

-package shoes;
-
-public class Sneakers extends Shoes {
-	public Sneakers(String name, double size) {
-		super(name, size);
-	}
-}