Java Design confusion

Question

I am having a bit of trouble with the design aspect of my JAVA program, there a couple of ways in which I have thought of doing, but I dont know which way is best, or if there is a better way to do it?. Below is an example of one way

 << ABSTRACT >>
 Rooms class
 extends extends extends
 Room TYPE U Connector X Connector U
 AGGREGATE walls - into each room type

The reason why I am getting a bit confused is that the 3 different types of rooms that I am using only differ in there property values(height,width etc..), but all have the same properties. Does this warrant creating a new class for EACH room type?.

Or should I do it the other way which is having the one rooms class and instantiating it three times for each room type and just changing its properties via setters and getters?.

because I would have to set each rooms properties and its aggregated wall properties which could get quite long!.

Any help is greatly appreciated.

• Dave Newton: Not sure if it's possible to answer in a meaningful way with the info given. If they're only different in size, it totally depends on how you want to identify/use them. It also sounds like you should have a ctor that takes dimensions rather than instantiating-then-setting.
• Chetan Kinger: You really need to explain your problem with more details if you want a good answer. Your question, as it stands, is almost impossible to understand. You should start by defining the problem : "Consider a house that has many rooms. Each room has different dimensions and different number of walls... I have come up with the following design and..". I hope this makes sense

Answer 1

If the rooms only differ by their property values, consider using a factory-style pattern. Here's a simple example:

class Room {
 // room properties
 int x, y, z;
 // constructor taking properties
 public Room (int x, int y, int z) {
 this.x = x;
 this.y = y;
 this.z = z;
 }
 // factory methods
 public static Room createRoomType1() {
 return new Room(100, 200, 300);
 }
 public static Room createRoomType2() {
 return new Room(400, 500, 600);
 }
}

The factory methods are like "preset" constructors for different types of rooms. This strikes a balance between repetition/property setting, and having too many classes.

• user969729: Yeah hmmm and what about say for the wall class when I instantiate say 4 walls for one room in the wall array list. Each wall might be a different size?. Can you have factory methods for those? like createroomType1 walls and then inside of that method instantiate the four walls that the room has?
• calebds: Whatever is common to all rooms, such as Wall instantiation, put into the Room constructor.