Referencing an Object Inside an Object
I am creating a game in Java and need to create a list of all of the rooms in it.
I have a 'Rooms' class that has the code for the room, i.e. room name, items in the room etc.
In the Room class I want to have a static ArrayList that has all of the room objects in the whole game in there. This is needed for a method I am working on.
I have created an ArrayList field:
private static ArrayList<Rooms> listOfRooms = new ArrayList<Rooms>();
In the initialisation of each instance of Rooms, I wish to add that instance to the listOfRooms ArrayList.
I assume you start with listOfRooms.add(), but what would you actually put in the parameter to add the current object to the list of Rooms objects?
java class
edited Nov 20 at 16:47
Andrea
4,48411743
asked Nov 20 at 16:38
Link
43119
add a comment |
I am creating a game in Java and need to create a list of all of the rooms in it.
I have a 'Rooms' class that has the code for the room, i.e. room name, items in the room etc.
In the Room class I want to have a static ArrayList that has all of the room objects in the whole game in there. This is needed for a method I am working on.
I have created an ArrayList field:
private static ArrayList<Rooms> listOfRooms = new ArrayList<Rooms>();
In the initialisation of each instance of Rooms, I wish to add that instance to the listOfRooms ArrayList.
I assume you start with listOfRooms.add(), but what would you actually put in the parameter to add the current object to the list of Rooms objects?
java class
edited Nov 20 at 16:47
Andrea
4,48411743
asked Nov 20 at 16:38
Link
43119
You need to get the static list and then add to it.
– Nicholas K
Nov 20 at 16:40
You'd better not use any collection as a static field, collections are mutable i.e. collie class able to modify internal state. If you really need a collection (I suppose you don't), try a singleton pattern. Enum singleton (Singleton of Bloch) choose is better. BTW, I suppose you've just need an enum.
– Victor Gubin
Nov 20 at 16:45
add a comment |
I am creating a game in Java and need to create a list of all of the rooms in it.
I have a 'Rooms' class that has the code for the room, i.e. room name, items in the room etc.
In the Room class I want to have a static ArrayList that has all of the room objects in the whole game in there. This is needed for a method I am working on.
I have created an ArrayList field:
private static ArrayList<Rooms> listOfRooms = new ArrayList<Rooms>();
In the initialisation of each instance of Rooms, I wish to add that instance to the listOfRooms ArrayList.
I assume you start with listOfRooms.add(), but what would you actually put in the parameter to add the current object to the list of Rooms objects?
java class
edited Nov 20 at 16:47
Andrea
4,48411743
asked Nov 20 at 16:38
Link
43119
I am creating a game in Java and need to create a list of all of the rooms in it.
I have a 'Rooms' class that has the code for the room, i.e. room name, items in the room etc.
In the Room class I want to have a static ArrayList that has all of the room objects in the whole game in there. This is needed for a method I am working on.
I have created an ArrayList field:
private static ArrayList<Rooms> listOfRooms = new ArrayList<Rooms>();
In the initialisation of each instance of Rooms, I wish to add that instance to the listOfRooms ArrayList.
I assume you start with listOfRooms.add(), but what would you actually put in the parameter to add the current object to the list of Rooms objects?
java class
java class
edited Nov 20 at 16:47
Andrea
4,48411743
asked Nov 20 at 16:38
Link
43119
edited Nov 20 at 16:47
Andrea
4,48411743
asked Nov 20 at 16:38
Link
43119
edited Nov 20 at 16:47
Andrea
4,48411743
edited Nov 20 at 16:47
Andrea
4,48411743
edited Nov 20 at 16:47
Andrea
4,48411743
4,48411743
asked Nov 20 at 16:38
Link
43119
asked Nov 20 at 16:38
Link
43119
asked Nov 20 at 16:38
Link
43119
43119
You need to get the static list and then add to it.
– Nicholas K
Nov 20 at 16:40
You'd better not use any collection as a static field, collections are mutable i.e. collie class able to modify internal state. If you really need a collection (I suppose you don't), try a singleton pattern. Enum singleton (Singleton of Bloch) choose is better. BTW, I suppose you've just need an enum.
– Victor Gubin
Nov 20 at 16:45
add a comment |
You need to get the static list and then add to it.
– Nicholas K
Nov 20 at 16:40
You'd better not use any collection as a static field, collections are mutable i.e. collie class able to modify internal state. If you really need a collection (I suppose you don't), try a singleton pattern. Enum singleton (Singleton of Bloch) choose is better. BTW, I suppose you've just need an enum.
– Victor Gubin
Nov 20 at 16:45
You need to get the static list and then add to it.
– Nicholas K
Nov 20 at 16:40
You need to get the static list and then add to it.
– Nicholas K
Nov 20 at 16:40
You'd better not use any collection as a static field, collections are mutable i.e. collie class able to modify internal state. If you really need a collection (I suppose you don't), try a singleton pattern. Enum singleton (Singleton of Bloch) choose is better. BTW, I suppose you've just need an enum.
– Victor Gubin
Nov 20 at 16:45
You'd better not use any collection as a static field, collections are mutable i.e. collie class able to modify internal state. If you really need a collection (I suppose you don't), try a singleton pattern. Enum singleton (Singleton of Bloch) choose is better. BTW, I suppose you've just need an enum.
– Victor Gubin
Nov 20 at 16:45
add a comment |
2 Answers
2
active
oldest
votes
You'd add this to the list; this being a reference to the current object (a Room in this case) being worked on:
listOfRooms.add(this);
Note though, having listOfRooms as a static member of the class is a bad idea. With this setup, you can only ever have one list, and anyone can alter the list however they want since it's public.
It would likely be much better to create something like a Hotel class and make it a member of that:
class Hotel {
ArrayList<Rooms> listOfRooms = new ArrayList<Rooms>();
}
Now you can at least have multiple hotels if necessary with separate lists of rooms, and to modify the rooms, code would at least require a reference to the hotel.
answered Nov 20 at 16:45
Carcigenicate
17.2k43058
add a comment |
Adding to what Carcigenicate said, it's always better to have more abstraction in object oriented programming.
For example, Hotel object has a Floor ArrayList in it. Each Floor object contains ArrayList of Room and so on.
answered Nov 20 at 16:51
Bhhargava Choppakatla
84
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
You'd add this to the list; this being a reference to the current object (a Room in this case) being worked on:
listOfRooms.add(this);
Note though, having listOfRooms as a static member of the class is a bad idea. With this setup, you can only ever have one list, and anyone can alter the list however they want since it's public.
It would likely be much better to create something like a Hotel class and make it a member of that:
class Hotel {
ArrayList<Rooms> listOfRooms = new ArrayList<Rooms>();
}
Now you can at least have multiple hotels if necessary with separate lists of rooms, and to modify the rooms, code would at least require a reference to the hotel.
answered Nov 20 at 16:45
Carcigenicate
17.2k43058
add a comment |
You'd add this to the list; this being a reference to the current object (a Room in this case) being worked on:
listOfRooms.add(this);
Note though, having listOfRooms as a static member of the class is a bad idea. With this setup, you can only ever have one list, and anyone can alter the list however they want since it's public.
It would likely be much better to create something like a Hotel class and make it a member of that:
class Hotel {
ArrayList<Rooms> listOfRooms = new ArrayList<Rooms>();
}
Now you can at least have multiple hotels if necessary with separate lists of rooms, and to modify the rooms, code would at least require a reference to the hotel.
answered Nov 20 at 16:45
Carcigenicate
17.2k43058
add a comment |
You'd add this to the list; this being a reference to the current object (a Room in this case) being worked on:
listOfRooms.add(this);
Note though, having listOfRooms as a static member of the class is a bad idea. With this setup, you can only ever have one list, and anyone can alter the list however they want since it's public.
It would likely be much better to create something like a Hotel class and make it a member of that:
class Hotel {
ArrayList<Rooms> listOfRooms = new ArrayList<Rooms>();
}
Now you can at least have multiple hotels if necessary with separate lists of rooms, and to modify the rooms, code would at least require a reference to the hotel.
answered Nov 20 at 16:45
Carcigenicate
17.2k43058
You'd add this to the list; this being a reference to the current object (a Room in this case) being worked on:
listOfRooms.add(this);
Note though, having listOfRooms as a static member of the class is a bad idea. With this setup, you can only ever have one list, and anyone can alter the list however they want since it's public.
It would likely be much better to create something like a Hotel class and make it a member of that:
class Hotel {
ArrayList<Rooms> listOfRooms = new ArrayList<Rooms>();
}
Now you can at least have multiple hotels if necessary with separate lists of rooms, and to modify the rooms, code would at least require a reference to the hotel.
answered Nov 20 at 16:45
Carcigenicate
17.2k43058
edited Nov 20 at 16:55
answered Nov 20 at 16:45
Carcigenicate
17.2k43058
answered Nov 20 at 16:45
Carcigenicate
17.2k43058
answered Nov 20 at 16:45
Carcigenicate
17.2k43058
17.2k43058
add a comment |
add a comment |
Adding to what Carcigenicate said, it's always better to have more abstraction in object oriented programming.
For example, Hotel object has a Floor ArrayList in it. Each Floor object contains ArrayList of Room and so on.
answered Nov 20 at 16:51
Bhhargava Choppakatla
84
add a comment |
Adding to what Carcigenicate said, it's always better to have more abstraction in object oriented programming.
For example, Hotel object has a Floor ArrayList in it. Each Floor object contains ArrayList of Room and so on.
answered Nov 20 at 16:51
Bhhargava Choppakatla
84
add a comment |
Adding to what Carcigenicate said, it's always better to have more abstraction in object oriented programming.
For example, Hotel object has a Floor ArrayList in it. Each Floor object contains ArrayList of Room and so on.
answered Nov 20 at 16:51
Bhhargava Choppakatla
84
Adding to what Carcigenicate said, it's always better to have more abstraction in object oriented programming.
For example, Hotel object has a Floor ArrayList in it. Each Floor object contains ArrayList of Room and so on.
answered Nov 20 at 16:51
Bhhargava Choppakatla
84
answered Nov 20 at 16:51
Bhhargava Choppakatla
84
answered Nov 20 at 16:51
Bhhargava Choppakatla
84
answered Nov 20 at 16:51
Bhhargava Choppakatla
84
84
add a comment |
add a comment |
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You need to get the static list and then add to it.
– Nicholas K
Nov 20 at 16:40
You'd better not use any collection as a static field, collections are mutable i.e. collie class able to modify internal state. If you really need a collection (I suppose you don't), try a singleton pattern. Enum singleton (Singleton of Bloch) choose is better. BTW, I suppose you've just need an enum.
– Victor Gubin
Nov 20 at 16:45