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I'm still learning swing and sockets both, so bear with me. To learn I'm making a chat client/server system. Right now, I'm working on the client. My classes are

  • Main (With the main method) code link
  • Window (Sets up Swing components) code link
  • ActLis(Handles all component action listeners from Window) code link
  • SocketManager(Manages my sockets) code link

I set up a SocketManager object in Main when the program runs, but then when ActLis needs to use that socket to send a message I don't know of a good way to get it from Main. Is what I'm doing completely ineffective and there is a better way to set it up, or is there a way to get my SocketManager object from my Main class that I don't know? (I realize there are other problems in my code, but I'm just trying to get sockets to work for a start, I'm having a hard time with them.)

user207421
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cgasser
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  • Just pass the `SocketManager` object to your `ActLis` class – Hunter McMillen May 13 '12 at 16:55
  • @HunterMcMillen Yes, but how would I do that? Every time I try I get a null pointer, because I need to create a **Main** object in **ActLis** to access **Main**'s **SocketManager** object. The **Main** object I create though is not the same one the **SocketManager** object had been set up in so it's null. – cgasser May 13 '12 at 17:06

2 Answers2

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You have a few options:

1) Have a ActLis object in the Main class and pass Main's reference to SocketManager to it

public class Main
{
   public static void main(String[] args)
   {
       ActList        a = new ActList(...);
       SocketManager sm = new SocketManager(...);

       a.sendMessageWithSocket(sm); //here you pass Main's reference to SocketManager 
   }                                //object to the ActLis class for use
}

2) Let the ActLis class have a reference to the SocketManager object, set in its constructor

public class ActLis
{
    private SocketManager sm;

    public ActLis(SocketManager sm)
    {
        this.sm = sm;
    }
}

These are probably the most simple ways to do this.

Hunter McMillen
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0

adding to Hunter McMillen's:

3) Make Main class, singleton. id est do not let more than one instance of it (If I've had understood your purpose, you don't need more than one instance of this class.) so just make a single instance of this class and keep its reference as a public static final field in it. (and of course don't let it be instantiated from outside this class:

    public class Main
    {
        public static final Main instance = new Main(/*args*/);

        private Main(/*args*/)
        {
            //blah blah
        }
    }

This way you can access your Socket field in Main form anywhere in your code with no problem.

Untitled
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