chatgroup.java

java3D game engine design of the source [three-dimensionalvirtualrealitynetworkprogram] - "virtual

// ChatGroup.java
// Andrew Davison, June 2003 ([e-mail])

/* Maintains info about all the current clients.

  A single ChatGroup object is used by all the 
  ChatServerHandler threads, so methods which
  manipulate the chatPeople ArrayList must be synchronised
  so that concurrent updates are prevented.

  ChatGroup handles the addition/removal of client details,
  the answering of "who" messages, and the broadcasting of
  a message to all the clients.
*/

import java.io.*;
import java.util.*;


public class ChatGroup
{
  private ArrayList chatPeople;  // holds a list of Chatter objects

  public ChatGroup()
  {  chatPeople = new ArrayList();  }


  synchronized public void addPerson(String cliAddr, int port, 
									     PrintWriter out)
  // add a new Chatter object to the list
  { chatPeople.add( new Chatter(cliAddr, port, out));  
    broadcast("Welcome a new chatter ("+cliAddr+", "+port+")");
  }


  synchronized public void delPerson(String cliAddr, int port)
  // remove the Chatter object for this person
  { Chatter c;
    for(int i=0; i < chatPeople.size(); i++) {
      c = (Chatter) chatPeople.get(i);
      if (c.matches(cliAddr, port)) {
        chatPeople.remove(i);
        broadcast("("+cliAddr+", "+port+") has departed");
        break;
      }
    }
  }  // end of delPerson()


  synchronized public void broadcast(String msg)
  /* Send msg to all the clients, including back to the
     original sender. */
  {
    Chatter c;
    for(int i=0; i < chatPeople.size(); i++) {
      c = (Chatter) chatPeople.get(i);
      c.sendMessage(msg);
    }
  }  // end of broadcast()


  synchronized public String who()
  /*  Returns a string of who is currently logged on, in the form
        "WHO$$ cliAddr1 & port1 & ... cliAddrN & portN & "
  */
  { Chatter c;
    String whoList = "WHO$$ ";
    for(int i=0; i < chatPeople.size(); i++) {
      c = (Chatter) chatPeople.get(i);
      whoList += c.toString();
    }
    return whoList;
  }  // end of who()

}  // end of ChatGroup class