How to have multiple keys for hashmap - hashmap

Question

private void createRooms()
{
myNeighbor = new HashMap <String, Room> ();
crumbs = new Item("Crumbs", "small crumbs of some kind of food", 100);
eggs = new Item("Raw Eggs", "a couple of raw eggs still contained within their egg shells", 1100);
cellPhone = new Item("Cell Phone", "Mike's cell phone he must have forgotten here...", 0);
textBooks = new Item("Textbooks", "Jay's textbooks, because he can't use his bedroom to store his stuff", 0);
poptarts = new Item("Pop Tarts", "an un-opened box of chocolate pop tarts that someone must have left behind...", 1500);
pizzaRolls = new Item("Pizza Rolls", "cooked steaming pizza rolls piled high", 2000);
clothes = new Item("Clothes", "clothes, a lot of clothes all over the floor and all over the room, who knows if they're clean or not...", 0);
// miningTools = new Item("Mining Tools", "pickaxes, drills, and everything else you need to extract rocks and minerals from the earth's crust", 100);
chips = new Item("Chips", "chip bag hidden away that is only half full now", 400);
hallway = new Room("in a dark hallway with crumbs scattered over the ground", crumbs);
kitchen = new Room("in a kitchen with raw eggs lying on the counter tops", eggs);
bathroom = new Room("in a bathroom with a stand up shower, a washer, a drier, and Mike's cell phone left behind laying on the counter", cellPhone);
livingRoom = new Room("in a living room with Jay's textbooks all over the room", textBooks);
upstairsLobby = new Room("in a lobby at the top of the stairs with a box of pop tarts on the ground", poptarts);
blakesRoom = new Room("in a dark room with towers of pizza rolls covering the desk and scattered across the bed", pizzaRolls);
jaysRoom = new Room("in a cluttered room with clothes covering every inch of the floor and nothing hanging on the walls", clothes);
mikesRoom = new Room("in a bed room with mining tools and a bag of chips hidden underneath a pillow on the bed", chips);
hallway.addNeighbor("north", kitchen);
hallway.addNeighbor("west", upstairsLobby);
hallway.addNeighbor("east", livingRoom);
kitchen.addNeighbor("west", bathroom);
kitchen.addNeighbor("south", hallway);
bathroom.addNeighbor("east", kitchen);
livingRoom.addNeighbor("west", hallway);
upstairsLobby.addNeighbor("north", jaysRoom);
upstairsLobby.addNeighbor("west", blakesRoom);
upstairsLobby.addNeighbor("east", mikesRoom);
upstairsLobby.addNeighbor("south", hallway);
blakesRoom.addNeighbor("east", upstairsLobby);
jaysRoom.addNeighbor("south", upstairsLobby);
mikesRoom.addNeighbor("west", upstairsLobby);
}
Room class
import java.util.HashMap;
/**
* Write a description of class Room here.
*
* #author (Christopher a date)
*/
public class Room
{
private String description;
private Item item;
private HashMap <String, Room> myNeighbor;
public Room (String pDescription)
{
description = pDescription;
item = null;
HashMap <String, Room> myNeighbor = new HashMap <String, Room> ();
}
public Room (String pDescription, Item pItem)
{
description = pDescription;
item = pItem;
}
public String getDescription()
{
return description;
}
public Item getItem()
{
return item;
}
public void addItem(Item i)
{
item = i;
}
public boolean hasItem()
{
if (item != null)
return true;
else
return false;
}
public void addNeighbor(String pDirection, Room r)
{
myNeighbor = new HashMap <String, Room> ();
myNeighbor.put(pDirection, r);
}
public Room getNeighbor(String pDirection)
{
Room next = myNeighbor.get(pDirection);
if(next != null){
return next;
}
else{
return null;
}
}
public Item removeItem()
{
Item temp;
temp = item;
item = null;
return temp;
}
public String getLongDescription()
{
String part1 = "You are " + description;
String part2 = "You see ";
if(item != null){
return part1 + "" + part2 + "" + item.getDescription() + "" + item.getCalories();
}
return part1;
}
}
Long story short, the point of this is to add Rooms and be able to naviage them and pick up items and drop them. It has just been brought to my attention as I try to run the program that I can't have multiple north/south/east/west keys. How can I get around this so I can make this work?

Answer 1

It wont allow me to comment so...
I am not sure what your ROOM class looks like but I am guessing it is intialized with a hasmap in the constuctor, and ahs a method called addNeighbor to actuallymodify this hash map?
----EDIT-----
Seeing your AddNeighbor method shows that you create a new hasmap every time you add a neighbor to the hashmap. There is no need and you alraedy craeted MyNeighbor in the constuctor, now you can just "put" they new key, value combination in the hash map
Just remove the line to create a new hasmap every time.

Answer 2

Assuming that you want to be able to write:
Room targetRoom = currentRoom.neighbour("north");
then you need to change your design.
The neighbours need to be member (ivars) of a room, like this for example:
class Room;
typedef HashMap<string, Room*> NeighbouringRooms;
public class Room {
...
public NeighbouringRooms const& neighbour() const {
return _neighbours;
}
private NeighbouringRooms neighbours;
}
(I've omitted some details inside the class, like adding a neighbour to a room.)
Now, since there are only 4 possible directions (N, S, E, W), an array of neighbours for each room would do the trick as well.
public class Room {
public Room neighbours[4];
...
}
Room room;
room.neighbour[north] = ... ;