Chat

ChatClient.java

import java.net.*;
import java.io.*;

public class ChatClient {
	public static void main(String[] args) {
		if(args.length != 2){
			System.out.println("Usage : java ChatClient <username> <server-ip>");
			System.exit(1);
		}
		Socket sock = null;
		BufferedReader br = null;
		PrintWriter pw = null;
		boolean endflag = false;
		try{
			sock = new Socket(args[1], 10001);
			pw = new PrintWriter(new OutputStreamWriter(sock.getOutputStream()));
			br = new BufferedReader(new InputStreamReader(sock.getInputStream()));
			BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in));
			// send username.
			pw.println(args[0]);
			pw.flush();
			InputThread it = new InputThread(sock, br);
			it.start();
			String line = null;
			System.out.println("Welcome to OSS Chat, '" + args[0] + "'");
			System.out.println("(/usage) to know how to use");
			while((line = keyboard.readLine()) != null){
				pw.println(line);
				pw.flush();
				if(line.equals("/quit")){
					endflag = true;
					break;
				}
			}
			System.out.println("Connection closed.");
		}catch(Exception ex){
			if(!endflag)
				System.out.println(ex);
		}finally{
			try{
				if(pw != null)
					pw.close();
			}catch(Exception ex){}
			try{
				if(br != null)
					br.close();
			}catch(Exception ex){}
			try{
				if(sock != null)
					sock.close();
			}catch(Exception ex){}
		} // finally
	} // main
} // class

class InputThread extends Thread{
	private Socket sock = null;
	private BufferedReader br = null;
	public InputThread(Socket sock, BufferedReader br){
		this.sock = sock;
		this.br = br;
	}
	public void run(){
		try{
			String line = null;
			while((line = br.readLine()) != null){
				System.out.println(line);
			}
		}catch(Exception ex){
		}finally{
			try{
				if(br != null)
					br.close();
			}catch(Exception ex){}
			try{
				if(sock != null)
					sock.close();
			}catch(Exception ex){}
		}
	} // InputThread
}

ChatServer.java

import java.net.*;
import java.io.*;
import java.util.*;
import java.text.SimpleDateFormat;
import java.util.Date;

public class ChatServer {
	public static void main(String[] args) {
		try{
			@SuppressWarnings("resource")
			ServerSocket server = new ServerSocket(10001);
			System.out.println("Waiting connection...");
			HashMap<String, PrintWriter> hm = new HashMap<String, PrintWriter>();
			HashSet<String> hs = new HashSet<String>();
			while(true){
				Socket sock = server.accept();
				ChatThread chatthread = new ChatThread(sock, hm, hs);
				chatthread.start();
			} // while
		}catch(Exception e){
			System.out.println(e);
		}
	} // main
}

class ChatThread extends Thread{
	private Socket sock;
	private String id;
	private BufferedReader br;
	private HashMap<String, PrintWriter> hm;
	//private boolean initFlag = false;
	private HashSet<String> spamwords;
	SimpleDateFormat time = new SimpleDateFormat("hh:mm:ss");
	public ChatThread(Socket sock, HashMap<String, PrintWriter> hm, HashSet<String> hs){
		this.spamwords = hs;
		this.sock = sock;
		this.hm = hm;
		try{
			PrintWriter pw = new PrintWriter(new OutputStreamWriter(sock.getOutputStream()));
			br = new BufferedReader(new InputStreamReader(sock.getInputStream()));
			id = br.readLine();
			broadcast(id + " entered.");
			System.out.println("[" + time.format((new Date())) + "]"
      + "[Server] User (" + id + ") entered.");
			synchronized(hm){
				hm.put(this.id, pw);
			}
			//initFlag = true;
		}catch(Exception ex){
			System.out.println(ex);
		}
	} // Constructor
	public void run(){
		try{
			String line = null;
			while((line = br.readLine()) != null){
				if(line.equals("/quit"))
					break;
				if(line.indexOf("/to ") == 0){
					sendmsg(line);
				}
				else if(line.equals("/userlist")){
					send_userlist();
				}
				else if(line.equals("/spamlist")){
					send_spamlist(spamwords);
				}
				else if(line.indexOf("/addspam ") == 0){
					add_spam(line);
				}
				else if(line.equals("/usage")){
					usage();
				}
				else {
					broadcast(id + " : " + line);
				}
			}
		}catch(Exception ex){
			System.out.println(ex);
		}finally{
			synchronized(hm){
				hm.remove(id);
			}
			broadcast(id + " exited.");
			try{
				if(sock != null)
					sock.close();
			}catch(Exception ex){}
		}
	} // run
	public void sendmsg(String msg){
		int start = msg.indexOf(" ") +1;
		int end = msg.indexOf(" ", start);
		if(end != -1){
			String to = msg.substring(start, end);
			String msg2 = msg.substring(end+1);
			Object obj = hm.get(to);
			if(obj != null){
				PrintWriter pw = (PrintWriter)obj;
				String spamword = check_spamwords(msg, spamwords);
				if (null == spamword)
					pw.println("[" + time.format((new Date())) + "]"
          + id + " whisphered. : " + msg2);
				else {
					pw = hm.get(id);
					pw.println("[" + time.format((new Date())) + "]"
          + " '" + spamword + "' is a spamword!");
				}
				pw.flush();
			} // if
		}
	} // sendmsg
	public void broadcast(String msg){
		synchronized(hm){
			Collection<PrintWriter> collection = hm.values();
			Iterator<PrintWriter> iter = collection.iterator();
			while(iter.hasNext()){
				PrintWriter pw = (PrintWriter)iter.next();
				if (pw!=hm.get(id)) {
					String spamword = check_spamwords(msg, spamwords);
					if (null == spamword)
						pw.println("[" + time.format((new Date())) + "]" + msg);
					else {
						pw = hm.get(id);
						pw.println("[" + time.format((new Date())) + "]"
            + " '" + spamword + "' is a spamword!");
					}
					pw.flush();
				}
			}
		}
	} // broadcast
	public void send_userlist() {
		Set<String> set = hm.keySet();
		Iterator<String> iterator = set.iterator();
		PrintWriter pw = hm.get(id);
		int i = 1;
		while(iterator.hasNext()){
			String username = (String)iterator.next();
			pw.println("User#" + i + ": " + username);
			pw.flush();
			i++;
		}
	} // send_userlist
	
	public String check_spamwords(String str, HashSet<String> set) {
		Iterator<String> iterator = set.iterator();
		while (iterator.hasNext()) {
			String spam = (String)iterator.next();
			if (str.contains(spam)) {
				System.out.println("[" + time.format((new Date())) + "]" + 
        "[Server] User (" + id  + ") used a spamword '" + spam + "'.");
				return spam;
			}
		}
		return null;
	}
	
	public void send_spamlist(HashSet<String> set) {
		//Set<String> set = hm.keySet();
		Iterator<String> iterator = set.iterator();
		PrintWriter pw = hm.get(id);
		int i = 1;
		while (iterator.hasNext()){
			String spam = (String)iterator.next();
			pw.println(i + "#: " + spam);
			pw.flush();
			i++;
		}
	}
	
	public synchronized void add_spam(String word) {
		PrintWriter pw = hm.get(id);
		int start = word.indexOf(" ") +1;
		String spamword = word.substring(start);
		spamwords.add(spamword);
		pw.println("[" + time.format((new Date())) + "]" + " new spamword '"
    + spamword + "' is added to spamlist");
		pw.flush();
	}
	
	public void usage() {
		PrintWriter pw = hm.get(id);
		pw.println("\t[How to use OSS Chat]");
		pw.println("Type message to send message to another users\n
    (/userlist) to print userlist\n(/spamlist) to print spamlist\n(/addspam) to add spamword");
		pw.println("(/[username] msg) to send message to [username]");
		pw.flush();
	}
}