import java.util.*;
// --------------------------------------------------
// By making this a class, you can easily add more information
// for each of your Chat room guests

class Chat {
   LinkedList m_lList = new LinkedList();
}
// --------------------------------------------------
class ChatArea{
// You could make this more dynamic, but it's a little
// simpler to keep the simple array approach

Chat chatArr[]= new Chat[100];
boolean stopFlag = false;

// Calling this routine should tell all of the chatserver
// threads to terminate

synchronized void setStopFlag()
   {
       stopFlag=true;
       notifyAll();
   }

// Add a new string to all linked lists
synchronized void putString(int index, String s)
   {
       for (int i= 0; i < chatArr.length; i++)
           if (chatArr[i] != null)
               chatArr[i].m_lList.addLast(s);
       notifyAll();
       System.out.println("putString: "+ s);
   }

// called to get the list of strings awaiting any given
// thread
synchronized String getStrings(int index)
   {
       int i, num;        
       String str;
       StringBuffer sb = new StringBuffer("");
       LinkedList lList;

       lList = chatArr[index].m_lList;
       num=lList.size();

       try{
           for (i=0; i < num; i++)
           {
               str = (String)lList.removeFirst();
               sb.append( str);
               sb.append("\n");
           }
       }
       catch (NoSuchElementException e)
       {
           System.out.println("Our List Count is Messed Up???");
       }
      
       return sb.toString();
   }

// called to wait for any new messages for a given thread

synchronized String waitForString(int index)
   {
       String str;

       do {
               str = getStrings(index);
               try {
                       if (str.length()== 0)               
                           wait(); 
                   }
                   catch (InterruptedException e)
                           {
                           System.out.println("Interrupted wait call");
                       }

               if (stopFlag)
                   return null;
       } while (str.length() == 0);
       return str;
   }
// Cread a new chat data structure
synchronized void addNewChat(int index)
   {
       chatArr[index] = new Chat();
   }

synchronized void removeChat(int index)
   {
       chatArr[index] = null;
   }


}