Java

edcasey15

I have two classes, Server and Handle. Handle is created by calling its constructor from within Server. I want Handle to be able to be able to access the states and call methods in Server.

I think I have to pass a reference to Handle that refers to Server but i am not sure exactly how to do this.

Please help

Ed

Dr Pepper

Declare a server object in the Handle class called parent of type server...

Server parent;

// Handle constructor:
public Handle(Server parent)
{
this.parent = parent;
}

Create a new handle in server as follows...

Handle handle = new Handle(this);

The instance of server is passed to the child (handle) and all of the variables/methods can be accessed as follows..

// In the handle class
parent.whateverInt = 1;
parent.setWhateverInt(1);
// etc...

All of the variables / methods you want to access in server from handle must be public AFAIK

OfflerCrocGod

Yep everything has to be public.....at that stage you may as well make everything static and just access stuff that way.

aidan_walsh

Originally posted by Dr Pepper
All of the variables / methods you want to access in server from handle must be public AFAIK

Unless you write Handle as a public inner class, in which case you could declare the methods private or protected. Then you would have to refer to Handle as Server.Handle if you want to work with it in another method.

Originally posted by OfflerCrocGod
at that stage you may as well make everything static and just access stuff that way.

Never, never make a method call static just for the sake of it... Firstly because of the overheads it causes with large classes, secondly, in this case, it just wouldn't be approporiate.

If hes going to be referencing one Server per handle class, the correct manner of going about it would be access\mutate methods.

Talliesin

Originally posted by doodle_sketch
Never, never make a method call static just for the sake of it... Firstly because of the overheads it causes with large classes, secondly, in this case, it just wouldn't be approporiate.

Do you know why static methods have more overhead in Java? This strikes me as curious because in C++ generally the opposite is true.
Is it related to Java being OO from the ground up (and static methods aren't very OO) where as C++ was more a matter of taking C and making it OO (among other changes)?

aidan_walsh

Don't quote me on this, but I think that every time a static method is called, the class gets re-cached instead of referencing a pre-cached object (which is what occurs in a normal access\mutate situation).

OfflerCrocGod

Originally posted by doodle_sketch
Never, never make a method call static just for the sake of it... Firstly because of the overheads it causes with large classes, secondly, in this case, it just wouldn't be approporiate.

If hes going to be referencing one Server per handle class, the correct manner of going about it would be access\mutate methods.

I know that's what I'd do, but in the context of this Q^ if the quick and nasty way works......use it, anyway the overhead I'd say (if this is being run on a PC - not PDA or Phone) would be minimal to unnoticable.

Hobbes

I guess it is based on what the PC is doing.

Gavin

Originally posted by edcasey15
I have two classes, Server and Handle. Handle is created by calling its constructor from within Server. I want Handle to be able to be able to access the states and call methods in Server.

I think I have to pass a reference to Handle that refers to Server but i am not sure exactly how to do this.

Please help

Ed

Another method, that may or may not be appropriate in your situation would be to create an Interface that the Server extends. Specify any methods that you wish Handle to be able to use (in the interface) and implement them in the Server. Create a variable of type this interface in the Handle then do the same as mentioned above. Create the Handle passing in the Server's this to it.

Handy way of seperating out the interface required.

Gav