com.dalsemi.shell.server
Class Server

java.lang.Object
  |
  +--java.lang.Thread
        |
        +--com.dalsemi.shell.server.Server

Direct Known Subclasses:

FTPServer, SerialServer, TelnetServer

public abstract class Server

extends Thread

A generic server. Servers will listen on some system resource for connection requests. When someone attempts to login, the server spins off a session to handle that login. Servers are designed to be multi-threaded, allowing multiple simultaneous connections.

Field Summary

protected Vector	sessions List of sessions created by this server.
protected boolean	shutdown Stops this server when set to true.

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

protected

Server() Initializes the server and creates the list of sessions (initially empty).

Method Summary

protected abstract Session	acceptNewSession() Waits for a connection request.
void	broadcast(String sendThis) Cycles through the list of know sessions, sending the specified message.
protected void	checkForNewSessions() Listens for connection requests.
protected abstract void	closeAllPorts() Cleans up any system resources held by this server.
String[]	getConnectedUsers() Gets an array of the names of all of the users that are currently connected to this server.
void	run() Starts the server.
void	sessionEnded(Session session) Notifies this server that a particular session is ending.
void	shutDown() Requests that the server stop taking connections and terminate any current sessions.

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getName, getPriority, getThreadGroup, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setDaemon, setName, setPriority, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

sessions

protected Vector sessions

List of sessions created by this server.

shutdown

protected boolean shutdown

Stops this server when set to true.

Constructor Detail

Server

protected Server()

Initializes the server and creates the list of sessions (initially empty).

Method Detail

run

public void run()

Starts the server. This method continuously loops checking for new connections until the shutdown field is set to true.

Overrides:

run in class Thread

checkForNewSessions

protected void checkForNewSessions()

Listens for connection requests. This method blocks until a request is received. Once the new session is created, it is added to the list of known sessions.

acceptNewSession

protected abstract Session acceptNewSession()

Waits for a connection request. This method should block until a request is received. When a request is made, it should create, initialize, and return a new Session to handle that connection.

Returns:

a new Session

shutDown

public void shutDown()
              throws IOException

Requests that the server stop taking connections and terminate any current sessions. Cycles through the list of known sessions, closing down each one and then cleaning up its own system resources.

sessionEnded

public void sessionEnded(Session session)

Notifies this server that a particular session is ending. Removes the closing session from the list of known sessions.

Parameters:

session - the session that has terminated

getConnectedUsers

public String[] getConnectedUsers()

Gets an array of the names of all of the users that are currently connected to this server.

Returns:

user names of all connected users

broadcast

public void broadcast(String sendThis)

Cycles through the list of know sessions, sending the specified message.

Parameters:

sendThis - message to send to all sessions

closeAllPorts

protected abstract void closeAllPorts()
                               throws IOException

Cleans up any system resources held by this server.