Question

I’m having some problems removing clients from a channellist.

This is the code i have at the moment:

Serverside:

private Hashtable<String, ArrayList<String>> channels = new Hashtable<String, ArrayList<String>>();

    public synchronized void logMeOut(String username) throws RemoteException {
        for(Client c : clients){
            if(c.findName().equals(username)){
                clients.remove(c);
                disconnectAllChans(username);
                System.out.println(username + " removed from clientlist.");
            }
        }
        updateJListForOnlineUsers(); //Callback for other clients to update the userlist.
    }

  public void disconnectAllChans(String username) throws RemoteException{
    for(Enumeration e = channels.elements(); e.hasMoreElements();){
        if(channels.contains(username)){
            channels.remove(username);
        }
    }
    updateJListForUsersInChannel();
    System.out.println("User " + username + " left all channel");
}

I have tried both if(channels.contains(username), and containsKey. None of them seems to do the work. When i leave the server, which runs the logout method, the client just hangs. I’m guessing its going on a foreverloop in that Enumeration loop.

EDIT: The client only hangs IF it has joined a channel. If the channellist for a user is empty, it quits right away.

Any ideas how the code should look?

**

Solution:

**

So yeah, i figured it out, but i wouldn’t have without you guys. Thanks

I just ran the disconnectmethod inside the disconnect all channels method which brainzzy posted. Heres the result:

@Override
public void disconnectChannel(String username, String channel) throws RemoteException{
    if(isUserInChannelX(username, channel)){
        channels.get(channel).remove(username);
        String message = "User " + username + " left the channel.";
        notifySelf(username, " You have left the channel " + channel);
        notifyChannelSystem(channel, "SYSTEM", message);
        updateJListForActiveChannels();
        if(channels.get(channel).isEmpty()){
            channels.remove(channel);
        } 
    }
}

public void disconnectAllChans(String username) throws RemoteException{
    for (String channel : channels.keySet()) {
    ArrayList<String> members = channels.get(channel);
        if (members.contains(username)) {
            disconnectChannel(username, channel);
            System.out.println("User " + username + " left channel " + channel);
        }
    }
    updateJListForUsersInChannel();
}

I feel kinda stupid ^^ Thanks people!

Answer 1

Replace the for with a foreach loop, makes it harder to make infinite loop errors like you’ve got yourself into by not handling the enumerator correctly:

for (String channel : channels.keySet()) {
    ArrayList<String> members = channels.get(channel);
    if (members.contains(username)) {
        members.remove(username);
    }
}

I think that’ll do what you want it to.