informclient.java

一个实现网络会议的软件.包含三个包.其中一个包需JMF的支持.

/*
 * Author: Naizheng Bian
 * Version:1.0
 * Date: 11/01/2001
 */


package serverPackage;

import java.util.*;
import java.io.*;
//import java.awt.*;
//import java.net.*;
import mediaPackage.*;
//import serverPackage.*;

/**
 * This Class informs other users about the events
 */
public class InformClient {
	
    /**
	 * This method informs other users about a event
	 * @param type The type of the event
	 * @param msg The chat message to be delivered
	 * @param userList The hashtable of the current logined users' configs
	 * @param outputStreamTable The hashtable of users' outputStreams
	 * @param UserConfig The config of the user who wants to inform others
	 * @return The vector of crashed users
	 */
    public Vector informUser(int type, String msg,Hashtable usersList, Hashtable outputStreamTable,
							UserConfig userConfig) {
    	Vector failedUsers = null;
        Enumeration e = usersList.elements();
        while (e.hasMoreElements()) {
             	UserConfig next = (UserConfig) e.nextElement();
		if (userConfig != null){
			if(next.getUserName().equals(userConfig.getUserName())) {
             			continue;
             		}
		}			 
		try {
			 try{				 
				String userName = next.getUserName();
				ObjectOutputStream ostream = 
				(ObjectOutputStream)outputStreamTable.get(userName);
              		 	ostream.writeObject(new Integer(type));
				if(type == Constants.LOGIN_USER)
					ostream.writeObject(userConfig);
				else if(type == Constants.LOGOUT_USER){
					ostream.writeObject(userConfig.getUserName());
				}
				else if(type == Constants.PUBLIC_CHAT){
					 ostream.writeObject(msg);
					 ostream.writeObject(userConfig.getUserName());						
					 ostream.writeObject(next.getUserName());
				}
				else if(type == Constants.PRIVATE_CHAT){
					 ostream.writeObject(msg);
					 ostream.writeObject(userConfig.getUserName());						 
					 ostream.writeObject(next.getUserName());
				}
				else if(type == Constants.START_SESSION ){
					 ;
				}
              	     		ostream.flush();
				ostream.reset();
			}catch(IOException ie ){
			}
               	}catch (Exception ee) {
			System.out.println("Exception");
                	if (failedUsers == null)
			 	failedUsers = new Vector();					
              		failedUsers.add(next.getUserName());
			System.out.println("failed user is:"+ next.getUserName());
              	}	
         }         
         return failedUsers;
    }	
	
	/**
	 * This method informs another user saying YES
	 * @param contentManagerList The table of contents (Redundant)
	 * @param usersList The list of other users
	 * @param strURL The new URL that was added
	 * @return The list of users that cannot be informed (assumed crashed)
	 */
	public Vector addToContentManager(Hashtable contentManagerList, Hashtable usersList,String strURL, 
									   Hashtable outputStreamTable) {
		 Vector crashedUsers = null;		
		 Enumeration e = usersList.elements();
		 while (e.hasMoreElements()) {
              	 UserConfig uList = (UserConfig) e.nextElement();
              	 try {
			String userName = uList.getUserName();
			ObjectOutputStream ostream = (ObjectOutputStream)outputStreamTable.get(userName);
              		ostream.writeObject(new Integer(Constants.UPDATE_CONTENT_MANAGER));
              		ostream.writeObject(strURL);
              		ostream.flush();
              	}catch (IOException ie) {
              		if (crashedUsers == null) {
              			crashedUsers = new Vector();
              	}
              	crashedUsers.add(uList.getUserName());              	
              }
         }
         
         return crashedUsers;
	}
	
	/**
	 * This method informs users about a URL being changed by the presenter
	 * @param contentManagerList The contents of the ContentManager (Redundant)
	 * @param usersList The list of other users
	 * @return The list of users that cannot be informed (assumed crashed)
	 */
	public Vector notifyURLChanged(Hashtable contentManagerList, Hashtable usersList, String newURL,
									Hashtable outputStreamTable)  
	{
		Vector crashedUsers = null;
		String key = getFileName(newURL);
	    	String strURL = (String) contentManagerList.get(key);     
		Enumeration e = usersList.elements();
		while (e.hasMoreElements()) 
		{
			UserConfig uList = (UserConfig) e.nextElement();
			int curUserCategory = uList.getUserCategory();			
			if (curUserCategory == Constants.USER)
			{
				try 
				{
					String userName = uList.getUserName();
					ObjectOutputStream ostream = 
							(ObjectOutputStream)outputStreamTable.get(userName);
					ostream.writeObject(new Integer(Constants.URL_CHANGED));
					ostream.writeObject(strURL);
					ostream.flush();
				}catch (IOException ie) 
				{
              			if (crashedUsers == null) {
              				crashedUsers = new Vector();
              			}
              			crashedUsers.add(uList.getUserName());
				}
			}
		}
		return crashedUsers;
	}
	
	/**
	 * This private method extract the name of the file from the URL
	 * @param urlStr The URL from which name has to be extracted
	 * @return The extracted name
	 */
	private String getFileName(String urlStr)
	{
		if (urlStr == "" || urlStr == null)
		{
			showMessage("In ReceiveFile class: URL is empty.");
			return null;
		}
		
		int nameStartIndex = urlStr.lastIndexOf("/");
		if(nameStartIndex == -1)
			nameStartIndex = urlStr.lastIndexOf("\\");		
		if(nameStartIndex == -1)
			nameStartIndex = urlStr.lastIndexOf("//");
		
		String fileName = null;
		if(nameStartIndex != -1)
			fileName = urlStr.substring(nameStartIndex + 1);
		else
		{
			showMessage("URL form error: " + urlStr 
						+ "\n URL should be in the form of protocol://Path/FileName");
		}
		return fileName;
	}
	
	/**
	 * This is a utility method that shows messages
	 * @param msg The messages to be shown
	 */
	private void showMessage(String msg)
	{
		System.err.println("UserManager: " + msg);
	}	

}