Question

Im trying to apply the state pattern on a multi threaded application.The problem is that the compiler doesnt like the fact that my class extends Thread. Here is the code :

public class ConnectionHandler  extends Thread 
     private State lockedState;
     public ConnectionHandler(Socket socket){
     ...
     lockedState = new LockedState(this);
     }
     public State getState(){}
    public void setState(State state){}

{

public interface State  {
    public void PASSWD(String pass);
    public void ACCESS(String file);
    public void getDIR();
    public void QUIT();
}

public class LockedState implements State  {
    ConnectionHandler connectionHandler;
    public LockedState(ConnectionHandler handler){

        connectionHandler=handler;
    }
    public void PASSWD(String pass){
    public void ACCESS(String file){}
    public void getDIR(){}
    public void QUIT(){}
}

The error i get is on constructor of ConnectionHandler : incompatible types required java.lang.Thread.State found : Networks2.LockedState. When i remove the extends Thread from Connectionhandler it doesnt give any errors but thats not an option.
So the question : What should i do so that the compiler doesnt complain ? Thanks

Answer 1

I think extending java.lang.Thread is a very bad idea. I doubt that you’re going to provide behavior that’s worth an extension.

I’m betting that you really want to implement java.lang.Runnable and have it executed by java.lang.Thread.