Класс: Классы "Док" и "Корабль".

package com.mycompany.Entitys;
 
import java.util.HashSet;
import java.util.Set;
 
public class NewMain {
    public static boolean razreshenie = true;
    public static void main(String[] args) {
        Doc doc1 = new Doc(3, "Caribic");
        Doc doc2 = new Doc(1, "Caribic bue");
        Ship pirate1 = new Ship(15, "Pirate Jack");
        Ship pirate2 = new Ship(10, "Pirate Jimmy");
        Ship pirate3 = new Ship(12, "Pirate Joe");
        Ship pirate4 = new Ship(8, "Pirate Jesy");
        System.out.println(doc1.setShip(pirate1));
        System.out.println(doc1.setShip(pirate2));
        System.out.println(doc1.setShip(pirate3));
        System.out.println(doc1.setShip(pirate4));
                
    }
}
class Doc {
 
    private int capacity;
    public String name;
    private Set<Ship> ships;
    
    public Doc() {
    }
    
    public Doc(int capacity, String name) {
        this.capacity = capacity;
        this.name = name;
        ships = new HashSet<>(this.capacity);
    }
    public String setShip(Ship sh) {
        if(capacity > ships.size()) {
            ships.add(sh);
        return "ship "+ sh.name +" is Doc";
        }
        else return "Doc is full";
    }
    public Set<Ship> getShip() {
        return ships;
    }
    
    public int getCapacity() {
        return capacity;
    }
 
    public void setCapacity(int capacity) {
        this.capacity = capacity;
    }
    
}
class Ship {
 
    public Ship() {
    }
    private int size;
    public String name;
 
    public Ship(int size, String name) {
        this.size = size;
        this.name = name;
    }
 
    public int getSize() {
        return size;
    }
 
    public void setSize(int size) {
        this.size = size;
    }
    
}

public interface Visitor {
}

public interface Authorizer extends Visitor {
    void authorize(CruiseShip ship);
}

public interface Dockable extends Visitor {
    void enter(Port port);
}

public class CruiseShip implements Dockable {
    private String name;
 
    private boolean isAuthorized;
 
    public CruiseShip(String name) {
        this.name = name;
    }
 
    public boolean isAuthorized() {
        return isAuthorized;
    }
 
    public void setAuthorized(boolean authorized) {
        isAuthorized = authorized;
    }
 
    public void requestAuthorization(Authorizer authorizer) {
        authorizer.authorize(this);
    }
 
    public String getName() {
        return name;
    }
 
    @Override
    public void enter(Port port) {
        requestAuthorization(port.getCaptain());
        port.tryAccept(this);
    }
}

public class Port {
    private List<CruiseShip> cruiseShips;
 
    private PortCaptain captain;
 
    public Port() {
        this.cruiseShips = new ArrayList<>();
        this.captain = new PortCaptain();
    }
 
    public void tryAccept(CruiseShip ship) {
        if (ship.isAuthorized()) {
            cruiseShips.add(ship);
            System.out.println(ship.getName() + " docked to pier " + cruiseShips.size());
        } else
            System.out.println(ship.getName() + " is not authorized to dock to pier " + (cruiseShips.size() + 1));
    }
 
    public PortCaptain getCaptain() {
        return captain;
    }
}

public class PortCaptain implements Authorizer {
    @Override
    public void authorize(CruiseShip ship) {
        ship.setAuthorized(Helper.randomBoolean());
    }
 
    private static class Helper {
        private static boolean randomBoolean() {
            return ThreadLocalRandom.current().nextBoolean();
        }
    }
}

public class Main {
    public static void main(String[] args) {
        CruiseShip queenMary = new CruiseShip("Queen Mary");
        CruiseShip princessAnastacia = new CruiseShip("Princess Ananstacia");
        CruiseShip stormbreaker = new CruiseShip("Stormbreaker");
 
        Port port = new Port();
 
        queenMary.enter(port);
        princessAnastacia.enter(port);
        stormbreaker.enter(port);
    }
}