Creating the Socket Class to Send and Receive Messages

The SocketClass.java file opens the socket to establish a connection with the Jabber server, to send and receive messages between an end user and the Jabber server. Listing 2-4 shows the contents of the SocketClass.java file:

Listing 2-4: The SocketClass.java File

 /*Imports required util classes*/ import java.util.*; /*Imports required io classes*/ import java.io.*; /*Imports required net classes*/ import java.net.*; /*Imports required swing classes*/ import javax.swing.*; /* class SocketClass-This class is used to open a socket and sends and receives Jabber messages. Constructor: SocketClass-This constructor creates GUI. sendername: This method is called to substracte sender name from input message. checkForError: This method is called to check whether the input string contains an error message or not. sendXMLToJabber: This method is called to send XML message to Jabber server. closeConnection: This method is called to close client socket. run: This method is called to listen server response sended by jabber server. */ class SocketClass implements Runnable {    /*Declares objects of Vector class.*/    Vector tagvactor;    /*Declares objects of PrintWriter class.*/    PrintWriter out = null;    /*     Declares objects of BufferedReader class.    */    BufferedReader in = null;    Socket clientsocket;    Thread inputmessagethread;    /*Declares objects of String class.*/    String errortype;    String resource="Home";    String username="";    String password="";    String sendername="";    String  recevername="";    String registrationstring;    String servermessage="";    String ipaddress="";    String endtagstr="";    /*Declares object of UserLogin class.*/    UserLogin userloginhandler;    /*Declares object of JabberClient class.*/    JabberClient jabberclient;    int portno;    int wait=1000;    public boolean isConnected=false;    public SocketClass(JabberClient jc)    {       jabberclient=jc;    }    /*    isConnected: This method is called retrieve socket state.    Parameter: N/A    Return Value: boolean    */    public boolean isConnected()    {       return isConnected;    }    /*    setUserLoginHandler: This method is called to set handler of the object of UserLogin class.    Parameter: userlogin-Object of UserLogin  class.    Return Value: N/A    */    public void setUserLoginHandler(UserLogin userlogin)    {       userloginhandler=userlogin;    }    /*    socketoOpenClass: This method is called to open a socket and gets input and output streams.    Parameter: ipaddress-Object of String class, portno, wait    Return Value: N/A    */    public void socketoOpenClass(String ipaddress, int portno, int wait)    {       this.ipaddress=ipaddress;       this.portno=portno;       this.wait=wait;       openPort(ipaddress,portno,wait);       if (clientsocket!=null)       {          isConnected=true;       }       else       { JOptionPane.showMessageDialog(null, "Server not found.", "Error", JOptionPane.PLAIN_MESSAGE);       return;       }       try       {          out = new PrintWriter(clientsocket.getOutputStream(), true);          in = new BufferedReader(new InputStreamReader(clientsocket.getInputStream()));       }       catch(Exception e)       {          e.printStackTrace();       }       inputmessagethread=new Thread(this);                inputmessagethread.start();    }    /*    sendSessionStartMessage: This method is called to create a XML message string.    Parameter: N/A    Return Value: String    */    public String sendSessionStartMessage()    {       String sessionStratString;       sessionStratString="<?xml version=\"1.0\"   encoding=\"UTF-8\" ?>\n";       sessionStratString=sessionStratString+" <stream:stream";       sessionStratString=sessionStratString+" to= \""+ipaddress +"\"";       sessionStratString=sessionStratString+"  xmlns=\"jabber:client\"";       sessionStratString=sessionStratString+" xmlns:stream=\"http://etherx.jabber.org/streams\">";       return sessionStratString;    }    /*    sendAuthorized:  This method is called to create a XML message string.    Parameter: ipaddress - Object of String class, portno, wait    Return Value: N/A    */    public String sendAuthorized()    {       String authentication;       authentication="<iq type=\"set\" id=\"1\">";       authentication=authentication+" <query xmlns=\"jabber:iq:auth\">";       authentication=authentication+" <username>"+username+"</username>";       authentication=authentication+" <password>"+password+"</password>";       authentication=authentication+" <resource>"+resource+"</resource> ";       authentication=authentication+" </query> ";       authentication=authentication+"</iq>";                         return authentication;    }    /*    sendRegistration:  This method is called to create a XML message string.    Parameter: ipaddress - Object of String class, portno, wait    Return Value: N/A    */    public String sendRegistration()    {       String registrationstr="";       registrationstr="<iq type='set' to='"+username+".localhost' id='1'>";       registrationstr=registrationstr+"<query xmlns='jabber:iq:register'>";       registrationstr=registrationstr+"<username>"+username+"</username>";       registrationstr=registrationstr+"<password>"+password+"</password>";       registrationstr=registrationstr+"</query></iq>";       return registrationstr;    }    /*    setUserNameAndPassword:  This method is called to set user name, password and servername    Parameter: username - Object of String class, password - Object of  String class, servername -    Object of  String class.    Return Value: N/A    */    public void setUserNameAndPassword(String username, String password, String servername)    {       this.username=username;       this.password=password;       this.ipaddress=servername;    }    /*    openPort:  This method is called to open a client socket.    Parameter: ipaddress - Object of String class, portno, timeinsec    Return Value: N/A    */    private void openPort(String ipaddress,int portno,int timeinsec)    {       String host;       if (ipaddress.trim()=="")       {          System.out.println("No IP Address Specified.");       }       else       {          SocketOpener sc=new SocketOpener(); Clientsocket=sc.openSocket(ipaddress,portno,timeinsec);       }    }    /*    run:  This method is called to listen server   response sended by jabber server    Parameter: N/A    Return Value: N/A    */    public void run()    {       int i=0;       String errororwarning="";       String errorstring="";       String inputstring="";       boolean starttag=false;       boolean endtag=false;       boolean startwritting=false;       String messagebody="";       String tagentity="";       Vector tagvactor;       tagvactor=new Vector();       int vactorindex=0;       int starttagsing=0;       while (true)       {          try          {             i=in.read();             if (i==-1)             {                break;             }             else             {                inputstring=inputstring+(char)i;                ervermessage=servermessage+(char)i;                if ((char)i=='<')                {                   starttag=true;                   starttagsing=1;                   stagentity="";                }                else                {                   if ((char)i=='/' && starttag==true)                   {                      if (starttagsing==1)                      {                         starttag=false;                         endtag=true;                         startwritting=false;                         vactorindex=vactorindex-1;                         if (vactorindex>=0) agvactor.removeElementAt(vactorindex);                      }                      tagentity=tagentity+(char)i;                   }                   else                   {                   starttagsing=0;                   if((char)i=='>')                {                   jabberclient.setServerResponse(servermessage);                   servermessage="";                   if (endtag&&endtagstr.equals("stream:stream"))                   {                      jabberclient.setStatusLabel("Logged Off");                      jabberclient.setStatus("notconnected");                      jabberclient.disableAndEnableMenuItems(true);                   }                   if (endtag)                   {                      endtagstr="";                      endtag=false;                   }                   if (starttag)                   {                      if (tagentity.endsWith("/"))                      { tagentity=tagentity.substring(0,tagentity.leng  th()-1);                      }                      sendername(tagentity);                      if (tagentity.equals("remove"))                      {jabberclient.setStatusLabel("Not Connected");                      jabberclient.setStatus(""); jabberclient.disableAndEnableMenuItems(true);                      } errorstring=checkForError(tagentity);                      if (errorstring.equals("unauthorized"))                      {                         jabberclient.setStatus(""); JOptionPane.showMessageDialog(null, "User name or                         password is invalid.", "Error",JOptionPane.PLAIN_MESSAGE);                      }                      if (errorstring.equals("user exists"))                      {                         if (jabberclient.getStatus().equals("waitforreg"))                         {                            jabberclient.setStatus("");                            JOptionPane.showMessageDialog(null,"User ID already exists, Please choose                            other User ID.", "Error", JOptionPane.PLAIN_MESSAGE);                         }                      }                      if (errorstring.equals("User not exists.")&&messagebody.equals(""))                      {                         jabberclient.setStatusLabel(" Room does not exist");                         JOptionPane.showMessageDialog(null,"Room does not                         exist.","Error",JOptionPane.PLAIN_MESSAGE);                      }                   else if (errorstring.equals("User notexists.")&&(!messagebody.equals("")))                   {                      messagebody="";                      JOptionPane.showMessageDialog(null,"User dose not                      exists.","Error",JOptionPane.PLAIN_MESSAGE);                   }                   if (tagentity.equals("feature var='http://jabber.org/protocol/muc'"))                   {                      sendXMLToJabber("<presence from='"+username+"@conference."+ipaddress+"/Home'                      to='"+jabberclient.getRoomName()+"@conference."+ipaddress+"/"+username+"'/>");                   }                   if (tagentity.indexOf("type='result'")!=-1)                   {                      String status=jabberclient.getStatus();                      if (status.equals("waitforauth"))                      {                         jabberclient.setStatusLabel("User authenticated");                         jabberclient.setStatus("auth");                         jabberclient.disableAndEnableMenuItems(false);                      }                      if (status.equals("waitforreg"))                      {jabberclient.setStatusLabel("Registered");                      jabberclient.setStatus("reg");                      }                   }                   startwritting=true;                   tagvactor.insertElementAt(tagentity,vactorindex);                   vactorindex=vactorindex+1;                   starttag=false;                   }                }                else                {                                                                                  if (startwritting==true&&tagentity.trim().equals("body"))                   {                      messagebody=messagebody+(char)i;                   }                   if (starttag)                   {                      tagentity=tagentity+(char)i;                   }                   if (endtag)                   {                      endtagstr=endtagstr+(char)i;                   }                }             }          }       }     }     catch(IOException ie)     {     }   }   isConnected=false;   } /* closeConnection: This method is called to close client socket. Parameter: N/A Return Value: N/A */ public void closeConnection() {    try    {       out.close();       in.close();       clientsocket.close();    }    catch (IOException e)     {       System.out.println(e);    }    isConnected=false; } /* sendXMLToJabber: This method is called to send XML message to Jabber server. Parameter: outputmessage - Object of String class. Return Value: N/A */ public void sendXMLToJabber(String outputmessage) {    String[] tokenizerstring=outputmessage.split("\n");    for (int i=0;i<tokenizerstring.length;i++ )    {       try       {          out.println(tokenizerstring[i]);          out.flush();       }       catch(Exception e)       {          System.out.println("error");          return;       }       out.flush();    } } /* checkForError:  This method is called to check whether the input string contains an error message or not. Parameter: tagentity - Object of String class. Return Value: String */ public String checkForError(String tagentity) {    String error="";    String codeid="";    if ( tagentity.equals("error code='403' type='auth'"))    {       return "unauthorized";    }    if (tagentity.equals("error  code='404' type='cancel'"))    {       return "User not exists.";    }    if ((tagentity.indexOf("code='401'")>1)||(tagentity.indexOf("code=\"401\"")>1))    {       return "unauthorized";    }    if (tagentity.equals("error code='409' type='cancel'"))    {       return "user exists";    }    if ((tagentity.indexOf("code='409'")>1)||(tagentity.indexOf("code=\"409\"")>1))    {       return "user exists";    }    return error; } /* sendername: This method is called to  substracte sender name from input message. Parameter: tagentity - Object of String class. Return Value: N/A */ public void sendername(String tagentity) {    if (tagentity.startsWith("message"))    {       sendername="";       recevername=""; if(tagentity.indexOf("from=")>0&&tagentity.indxOf("to=")>0)       {          sendername=tagentity.substring(tagentity.indexOf("from=")+6,tagentity.indexOf("to=")-2);       }       if (tagentity.indexOf("to=")>0&&tagentity.indexOf("type=")>0)       { recevername=tagentity.substring(tagentity.indexOf("to=")+4,tagentity.indexOf("type=")-2);       }     }   } } class SocketOpener {    private Socket socket;    public Socket openSocket(String hostip,int portnumber, int timeinsec)    {       try       {          socket=new Socket(hostip,portnumber);       }       catch(IOException ie)       {          System.out.println("IE:::::::::: " +ie);       }       return getSocket();    }    public SocketOpener()    {    }    public Socket getSocket()    {       return socket;    } }; 

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In the above code, the constructor of the SocketClass class takes the object of the JabberClient class to invoke the methods of the JabberClient class.

The methods defined in Listing 2-4 are:

• sendername(): Retrieves the sender’s name from the input message received from the Jabber server.

• checkForError(): Checks whether or not the input string contains an error message.

• sendXMLToJabber(): Sends an XML message to the Jabber server.

• closeConnection(): Closes the client socket from the Jabber server.

• run(): Listens to the server response sent by the Jabber server.

• isConnected(): Determines whether or not a client socket is connected to the Jabber server.

• setUserLoginHandler(): Sets the handler of the object of the UserLogin class.

• socketoOpenClass(): Calls the openPort() method to open a client socket and gets input and output streams to send and receive messages.

• sendSessionStartMessage(): Creates an XML message string to initialize the session of an end user.

• sendAuthorized(): Creates an XML message string to authenticate the end users.

• sendRegistration(): Creates an XML message string to sign up for a new account with the Jabber server.

• setUserNameAndPassword(): Sets the user name, password, and Jabber server name.

• openPort(): Opens a client socket by using the IP address and port number of the Jabber server.