chatclient.java

The chat room application that using JAVA to development.

/////////////////////////////////////////
// Java Programming Course, job-1
// Date: 2008/3/31
/////////////////////////////////////////
import java.io.*;
import java.net.*;
import java.util.StringTokenizer;


public class ChatClient implements Runnable
{
    static Socket clientSocket = null;
    static PrintStream os = null;
    static InputStreamReader bReader = null;
    static BufferedReader is = null;
    static InputStreamReader inputReader = null;
    static BufferedReader inputLine = null;
    static boolean closed = false;
    static boolean getName = false;
    static String userName = null;
    static boolean busy = false;
    
    
    public static void main(String[] args) 
    {
        // The default port	
	    int port_number=8000;
        String host="localhost";
        String userInput;
 
	    if (args.length < 2)
	    {
		    System.out.println("Usage: java ChatClient [ServerName] [PortNumber]  \n"+
				                "Now using default setting --> host="+host+", port_number="+port_number);
	    } 
	    else 
	    {
		    host=args[0];
		    port_number=Integer.valueOf(args[1]).intValue();
	    }
	    
	    // Initialization section:
	    try 
	    {
            inputReader = new InputStreamReader(System.in);
            inputLine = new BufferedReader(inputReader);            
            clientSocket = new Socket(host, port_number);
            os = new PrintStream(clientSocket.getOutputStream());
            bReader = new InputStreamReader(clientSocket.getInputStream());
            is = new BufferedReader(bReader);      
        }
        catch (UnknownHostException e) {
            reconnect();
        }
        catch (IOException e) {
            reconnect();
        }
            
	    // If everything has been initialized then we want to write some data
	    // to the socket we have opened a connection to on port port_number
        if (clientSocket != null && os != null && is != null) 
        {
            try 
            {
		        // Create a thread to read from the server
                new Thread(new ChatClient()).start();
		
		        while (!closed) 
		        {
		            userInput = inputLine.readLine();
		            
		            if (getName)
		            {
		                String s = "> ";
		                if (userInput != null)
		                {
			                userName = userInput;
			                userName = userName.concat(s);
			                getName = false;
			            }
			            else
			            {
			            	break;	
			            }	
		            }
		            
		            if (!busy)
                        os.println(userInput); 
                }

		        os.close();
		        is.close();
		        clientSocket.close();   
            } 
            catch (IOException e) {
                System.err.println("IOException:  " + e);
            }
        }
    }
    
    
    //
    // Read string from ChatServer side, and print to ChatClient's console.
    //
    public void run()
    {		
	    String responseLine, outresponse;
	    boolean ln = false;
	    
	    // Keep on reading from the socket till we receive the "Bye" from the server,
	    // once we received that then we want to break.
	    try
	    { 
	        while ((responseLine = is.readLine()) != null) 
	        {
	            if (responseLine.startsWith("Username")) {
	                System.out.print(responseLine);
	                getName = true;
	            }
	            else {
    	            if (userName != null && responseLine.startsWith(userName)) {    
    		            System.out.print(responseLine);
    		            ln = true;
    		        }
    		        else if (responseLine.startsWith("kick ")) {
    		            System.out.println("kick by someone, bye!");
    		            os.println("client end"); 
    		            os.close();
				        is.close();
				        clientSocket.close();  
    		            System.exit(0);
    		        }
    		        else if (responseLine.startsWith("[busy]")) {
    		            busy = true;
    		        }
    		        else if (responseLine.startsWith("[nonbusy]")) {
    		            busy = false;
    		        }
    		        else {
    		            if (ln) {
    		                System.out.println();
    		                ln = false;
    		            }
    		            
    		            System.out.println(responseLine);
    		        }
		        }
		        
		        if (responseLine.indexOf("*** Bye") != -1)
		        {
		        	os.close();
				    is.close();
				    clientSocket.close();  
    		        System.exit(0);
		        }    
	        }
            closed = true;
	    } 
	    catch (IOException e) {
	        System.err.println("IOException:  " + e);
	    }
    }
    
    
    // 
    // If connection failed using this function to do the reconnection. 
    // Command: "/connect hostname portnumber " 
    //
    public static void reconnect()
    {
        String response;
        
        System.err.println("**** The server does not exist. Please type different domain and/or port.");

        try
        {
            while ((response = inputLine.readLine()) != null)
            {
                if (response.indexOf("/connect ") != -1)
                {
                    StringTokenizer st = new StringTokenizer(response);
                    String _host = null;
                    String _port = null;
                    int pn = 0;
                    
                	_host = st.nextToken();
                	_host = st.nextToken();
                	_port = st.nextToken();
                   
                    if (_host != null && _port != null)
		                pn=Integer.valueOf(_port).intValue();
		            else
		                continue;
		            
		            try {
		                clientSocket = new Socket(_host, pn);
		                os = new PrintStream(clientSocket.getOutputStream());
                        bReader = new InputStreamReader(clientSocket.getInputStream());
            			is = new BufferedReader(bReader);
                    }
                    catch (UnknownHostException e) {
                    	System.out.println("**** The server does not exist. Please type different domain and/or port.");
                        continue;
                    }
                    catch (ConnectException e) {
                    	System.out.println("**** The server does not exist. Please type different domain and/or port.");
                    	continue;
                    }
                    if (clientSocket != null && os != null && is != null)
		            	break;
		        }
            }
        } 
        catch (IOException ee) {
            System.err.println("IOException:  " + ee);
        }
    }
}