Looking to be able to send data to ONE Connection

[john price]

I am looking to be able to send data to ONE connection. Here is what I have (it works fine) to send to all connected clients...

private void tellEveryone(String message) {
Iterator it = clientOutputStreams.iterator();
	while(it.hasNext()) {
		try {
		PrintWriter writer = (PrintWriter) it.next();
		writer.println(message);
		writer.flush();
		}
		catch(Exception ex) {
		ex.printStackTrace();
		}
	}
	}

I am looking to find how to make a separate method on how to send to one. If you could help, that would be great... I need to know how to do the comment below...

private void tellUser(String message, SocketAddress sockaddr) {
try {
//Writer.printTo(sockaddr, message)
}
catch (Exception ex) {
ex.printStackTrace();
}
}

Thanks,
cc11rocks

[Rob Spoor]

You need a mapping from client addresses to PrintWriters. I'm guessing that right know, clientOutputStreams is a Collection, List or Set. Perhaps a Map<SocketAddress,PrintWriter> is a better idea. Line 2 of your first method requires only minimal change:

//Iterator it = clientOutputStreams.iterator();
Iterator it = clientOutputStreams.values().iterator();

Line 3 of the second method becomes the following:

//Writer.printTo(sockaddr, message)  
PrintWriter writer = clientOutputStreams.get(sockaddr);
if (writer != null)
{
    writer.println(message);
}

[john price]

clientOutputStreams currently is an ArrayList...
Your answer seems so simple. Still trying to figure it out lol :P
cc11rocks

[john price]

Been thinking about it...If I could get this to work (Maybe you could suggest something?) :

private void tellUser(String message, ArrayList array) {
Iterator it = array.iterator();
try {
PrintWriter writer = (PrintWriter) it.next();
writer.println(message);
writer.flush();
}
catch (Exception exaf) {
exaf.printStackTrace();
}
}

I just have to find a way to get the array variable right... If you would like me to post the full server code, I can and will. It's less than 200 lines, including GUI code, etc. I can probably shorten it (to show you what I am doing) to 100 or less.
Thanks,
cc11rocks

EDIT: Got this working. Basically they can message themselves from this. I just need to make the ArrayList global (I know there is no global in Java, but I can't think of the word)? Then, remove everything from the ArrayList and add the one I want? This seems inefficienct. If this isn't do-able, go ahead and tell me. Thank you!

[Rob Spoor]

You lost me there. Can you please add your new code, as it's not too long?

[john price]

Took out the Unnecessary stuff...

try {
	ServerSocket serverSock = new ServerSocket(5000);
		while(true) {
		Socket clientSocket = serverSock.accept();
		PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());
		clientOutputStreams.add(writer);
		Thread t = new Thread(new ClientHandler(clientSocket, writer));
		t.start();
		System.out.println("got a connection");
		}
	}
	catch(Exception ex) {
	System.out.println("From System");
	ex.printStackTrace();
	}

public class ClientHandler implements Runnable {
		BufferedReader reader;
		Socket sock;
		public ClientHandler(Socket clientSocket, PrintWriter writer) {
			try {
			ArrayList userList = new ArrayList();
			userList.add(writer);
			tellUser("Hello world", userList); //This is where they can talk to themselves.  Only this user can see this message.  I added a working method below....
				sock = clientSocket;
				InputStreamReader isReader = new InputStreamReader(sock.getInputStream());
				reader = new BufferedReader(isReader);
				}
			catch(Exception ex) {
				ex.printStackTrace();
			}
		}
	public void run() {
	String message;
		try {
			while ((message = reader.readLine()) != null) {
			checkIP(sock.getRemoteSocketAddress());   //This checks the bad IP addresses in an ArrayList...
			if (checked_Baggage) {
			input.setText(input.getText() + "\n" + sock.getRemoteSocketAddress() + " : " + message);
			input.setCaretPosition(input.getDocument().getLength());
			if (message.startsWith("talkMyself") {
			tellUser(message, userList);
			}
			else {
				test(message); //This is a filter (for words I don't want people using).  If it passes, it sends it to everyone...
			}
		}
}
		}
		catch(Exception ex) {
		ex.printStackTrace();
		}
	}
	}

So if I could figure out someway to do this NOT in local variables, I would be able to do the PM's.

EDIT : Guess I should add the method tellUser...

private void tellUser(String message, ArrayList array) {
Iterator it = array.iterator();
try {
PrintWriter writer = (PrintWriter) it.next();
writer.println(message);
writer.flush();
}
catch (Exception exaf) {
exaf.printStackTrace();
}
}

[john price]

So basically, I've got half of the PM done. I would send the message back to the "host" of the message. And the other person. I/we have to figure out the other person. I have no clue. I've tried to think this out, but idk. I don't use lists very much and I'm not very familiar with maps, etc so maybe this is why I'm having trouble. There has to be a solution to this...
cc11rocks

[Paul Clapham]

john price wrote: I don't use lists very much and I'm not very familiar with maps, etc so maybe this is why I'm having trouble. There has to be a solution to this...

You seem to have identified the problem quite clearly. The solution should be equally clear, then. Learn about lists and maps. Here's a link to the Collections tutorial.

[john price]

The articles were very confusing for me. I am under the impression I am supposed to use a Map? And do you see the solution?
cc11rocks

[Paul Clapham]

john price wrote:The articles were very confusing for me.

Then keep reading until you aren't confused. This is a basic Java topic so you really should master it before trying to write non-trivial programs.

I am under the impression I am supposed to use a Map?

That's what Rob Spoor suggested, I haven't read the thread in detail but I would go along with that.

[john price]

Now that I've read the articles and seen his response, it makes sense. He's already given me the answer :P. I will read more though.
cc11rocks

[john price]

Think I got it now...

if (message.startsWith("PM")) {
				if (message.contains("\\")) {
					int where = message.lastIndexOf('\\');
					String PM_IP = message.substring(2, where);
					
					message = message.substring (1 + where, message.length());
					PM(PM_IP, "PM : " + message);
				}
			}

At the beginning of the program :

Map<String, PrintWriter> private_Message = new HashMap<String, PrintWriter>();

In the thread, in the run() method BEFORE the try statement...

String temp_String = sock.getRemoteSocketAddress().toString();
			int where_1 = temp_String.lastIndexOf(':');
			temp_String = temp_String.substring(0, where_1);
			private_Message.put(temp_String, globalWriter);

To make this user friendly, could I add a Map to it. Something like :

Map<String, String> userName_Connected_To_private_Message = new HashMap<String,String>();

Later...

String tempString = sock.getRemoteSocketAddress().toString();
			int where1 = tempString.lastIndexOf(':');
			tempString = tempString.substring(0, where1);
userName_Connected_To_private_Message.put(userName, tempString);

Would this work? How would I connect the HashMaps? Would I call the values() method? Then I use the get method for the string. Then, I use the values and then get method for the PrintWriter. Is there a better way to do this?
Thanks,
cc11rocks

[john price]

Believe I figured it out...

public class ClientHandler implements Runnable {
		BufferedReader reader;
		Socket sock;
		ArrayList userList;
		public ClientHandler(Socket clientSocket, PrintWriter writer) {
			try {
			userList = new ArrayList();
			userList.add(writer);
			tellUser("Hello world", userList);
				sock = clientSocket;
				InputStreamReader isReader = new InputStreamReader(sock.getInputStream());
				reader = new BufferedReader(isReader);
				globalWriter = writer;
				}
			catch(Exception ex) {
				ex.printStackTrace();
			}
		}
	public void run() {
	String message;
	String prev_Name = null;
	String stringName = null;
	System.out.println(sock.getRemoteSocketAddress());
			String temp_String = sock.getRemoteSocketAddress().toString();
			int where_1 = temp_String.lastIndexOf(':');
			temp_String = temp_String.substring(0, where_1);
			System.out.println(temp_String);
			private_Message.put(temp_String, globalWriter);
		try {
			while ((message = reader.readLine()) != null) {
			checkIP(sock.getRemoteSocketAddress()); 
			if (checked_Baggage) {
			else if (message.startsWith("talkMyself")) {
			tellUser(message, userList);
			}
			//else if (message.startsWith("PM")) {
			else if (message.startsWith("PM")) {
			String user_Name = null;
				if (message.contains("\\")) {
					int where = message.lastIndexOf('\\');
					String PM_IP = message.substring(2, where);
					try {user_Name = name.get(PM_IP);}
					catch (Exception adfa) {adfa.printStackTrace();}
					if (user_Name != null) {
					message = message.substring (1 + where, message.length());
					private_Message.get(user_Name);
					PM(user_Name, "PM : " + message);
					}
				}
			}
			else if (message.startsWith("setName")) {
				stringName = message.substring(7, message.length());
				if ((name.containsValue(prev_Name)) && (name.containsKey(prev_Name))) {
					try {
					name.remove(prev_Name);
					}
					catch (Exception exf) {
					exf.printStackTrace();
					}
				}
				prev_Name = stringName;
				System.out.println(stringName);
				name.put(stringName, temp_String);
			}
			else {
				test(message);
			}
		}
}
}
		catch(Exception ex) {
		ex.printStackTrace();
		}
	}
	}

PM(String sockaddr, String message) {}

private void PM(String sockaddr, String message) {
	Iterator it = private_Message.values().iterator(); 
	PrintWriter writer = private_Message.get(sockaddr);
if (writer != null)
{
    writer.println(message);
	writer.flush();
}
	}

To send the PM back to the user that sent it, call the tellUser() method with the "PM : " + message. It's actually not that hard... Thanks for helping guys! I really appreciate it!
cc11rocks

[john price]

I held off resolving this until I had tested it on at least 4 computers and at least 3 internet connections. Today, I have and it works beautifully (I MAY have changed it since then). Anyway, thank you guys for your help!

John Price

EDIT : Now that I think back, I did change it. I made it user friendly ("person@message"). I also made it send back to the person who sent it. I also formatted the message differently, but the general concept is the same, involving pretty much the same method.