how to make an object migrate from one container object to another. (like software agent!)

Question

Suppose I have two objects of PARKING class that are respectively P1 and P2. PARKING class have unique identifier (UUID). I also have an object of class CAR which its name is mycar.

My car is currently built in P1 and now wants to migrate to P2.

Here is some code:

public class PARKING {

    public String ID = new String();
    ID  = UUID.randomUUID().toString();
    CAR car;

    public PARKING(CAR car) {
        this.car = car;
    }
    public PARKING (){

        }
    }


    public class CAR {

        public int ID;
        public String name = new String();

    }

    public static void main(String[] args) {
        CAR mycar = new CAR();
        PARKING P1 = new PARKING(mycar);
        PARKING P2 = new PARKING();   
    }    
}

Note that I don't want that P2 take mycar. I mean something like this P2.setCAR (P1.getCAR());

I want the car itself migrate from its current object which is P1 to another object which is P2.

I hope I have explained the problem clearly. Thanks in advance.

So you want to create a method that takes the parameters `PARKING p1, PARKING p2` that moves the cars in between? What's the issue you're having with making that method? — Draken, Apr 28 '16 at 13:12
Since it's `PARKING` that has a reference to `Car`, it's up to that class to handle the switch (either by the setter/getter combo you you described, or by other means). You can't have a `Car` switch parking lots without involvement of the Parking class. — Kayaman, Apr 28 '16 at 13:19

Draken · Answer 1 · 2016-04-28T13:50:24.870

If I've understood your query, it's quite simple what you want to do, here is an example method that can complete that:

public void moveCars(PARKING toMoveFrom, PARKING toMoveTo){
    //Checking a car can be moved from A to B
    if (toMoveFrom.car != null && toMoveTo.car == null){
        //Put car in B
        toMoveTo.car = toMoveFrom.car;
        //Remove car from A
        toMoveFrom.car = null;
    }
    else{
        //Either car blocking way or no car in original parking, handle error
    }
}

This is assuming you have made the PARKING.car property public or added a public getter/setter so you can access it. If however you want the car to be able to move itself, then you need to create a property on the Car class that stores the parking as well and change it via that instead. Choices, but that's up to you

how to make an object migrate from one container object to another. (like software agent!)

1 Answers1