: Class LoginServerThread

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Class LoginServerThread

java.lang.Object
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  +--java.lang.Thread
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        +--de.cgarbs.net.LoginServerThread

Direct Known Subclasses:: EchoServerThread

public abstract class LoginServerThread
extends java.lang.Thread

This class handles a connection from a client to a LoginServer.

Communication to this server thread is done using plain text. You can use a telnet to chat with your server or write your own client. It shouldn't be hard to write an SMTP or HTTP server using this package.

This server thread reacts to commands. A command is a string that is ended by a space. Anything after the space up to the end of a line is considered data. For example the line SAY Hello Bob! contains the command SAY and the data Hello Bob!. All server threads must provide the commands USER, PASS, QUIT and HELP. You may define as many other commands as you like.

Before any user-defined commands can be executed, the client has to log in using the USER and PASS commands. After that, any user defined commands can be executed. The commands QUIT and HELP can be executed at any time.

In order to write your own LoginServerThread you must create your own class that extends this class. Overwrite all abstract methods with your own. Your class must also have a Constructor that calls the Constructor of this class (Any ideas of how to come around this?). The main functionality or your server will reside in the validCommand() and parseCommand() methods. The other methods are mainly used for session handling and user authentification.

This class is licensed under the GNU GENERAL PUBLIC LICENSE.

Version:: 0.0.2
Author:: Christian Garbs
See Also:: LoginServer

Field Summary

protected LoginServer myServer
          a reference to the LoginServer that has spawned this LoginServerThread

protected java.io.PrintWriter out
          the output stream to the client

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

LoginServerThread(LoginServer myServer, java.io.PrintWriter logStream, java.util.Hashtable passwd, java.net.Socket socket)
          standard constructor

Method Summary

protected abstract void doubleLogin()
          tells the client that this user is already logged on and the connection will be closed

java.net.InetAddress getClientIP()
          returns the IP address of the client

long getID()
          returns the ID of this LoginServerThread

java.lang.String getUsername()
          returns the username of the user logged on

protected abstract void gotUser()
          tells the client that a USER command was successful

protected abstract void invalidCommand()
          tells the client that the given command was invalid

protected void log(java.lang.String message)
          writes a message to the log stream

protected abstract void login()
          tells the client that the login was successful

protected abstract boolean loginFailed(int cnt)
          tells the client that the login was unsuccessful and decides if the connection shall be closed

protected abstract void noPassGiven()
          tells the client that the PASS command must be followed by a password

protected abstract void noUserGiven()
          tells the client that the USER command must be followed by a username

protected abstract void parseCommand(java.lang.String command, java.lang.String data)
          This method handles non-standard client commands.

protected abstract void prompt()
          tells the client that it can send a command

void run()
          This method handles the communication with the client.

protected abstract void sendPass()
          tells the client to send a PASS command

protected abstract void sendUser()
          tells the client to send a USER command

protected abstract void sessionEnd()
          tells the client that the connection will be closed

protected abstract void sessionStart()
          tells the client that the connection is established

protected abstract void showHelp()
          sends a list of supported commands to the client

void shutdown()
          immediately closes connection to the client

protected abstract boolean validCommand(java.lang.String command)
          checks whether a command sent from the client is allowed

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getContextClassLoader, getName, getPriority, getThreadGroup, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, 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

out

protected java.io.PrintWriter out

the output stream to the client

myServer

protected LoginServer myServer

a reference to the LoginServer that has spawned this LoginServerThread

Constructor Detail

LoginServerThread

public LoginServerThread(LoginServer myServer,
                         java.io.PrintWriter logStream,
                         java.util.Hashtable passwd,
                         java.net.Socket socket)

standard constructor

Parameters:: myServer - reference to the LoginServer that spawned this LoginServerThread; logStream - log messages go here; passwd - valid username/password pairs (usernames=keys, passwords=values); socket - the socket to the client

Method Detail

getID

public long getID()

returns the ID of this LoginServerThread

Returns:: the ID of this LoginServerThread

log

protected void log(java.lang.String message)

writes a message to the log stream

Parameters:: message - the message to write

getClientIP

public java.net.InetAddress getClientIP()

returns the IP address of the client

Returns:: the IP address of the client

shutdown

public void shutdown()

immediately closes connection to the client

showHelp

protected abstract void showHelp()

sends a list of supported commands to the client

getUsername

public java.lang.String getUsername()

returns the username of the user logged on

Returns:: name of user (null before successful login)

validCommand

protected abstract boolean validCommand(java.lang.String command)

checks whether a command sent from the client is allowed

Parameters:: command - command from client
Returns:: true - command is valid

doubleLogin

protected abstract void doubleLogin()

tells the client that this user is already logged on and the connection will be closed

sessionStart

protected abstract void sessionStart()

tells the client that the connection is established

sessionEnd

protected abstract void sessionEnd()

tells the client that the connection will be closed

parseCommand

protected abstract void parseCommand(java.lang.String command,
                                     java.lang.String data)

This method handles non-standard client commands. (It does the thing your server is designed for)

Parameters:: command - command from client (first string token); data - data from client (all but first string token)

invalidCommand

protected abstract void invalidCommand()

tells the client that the given command was invalid

noUserGiven

protected abstract void noUserGiven()

tells the client that the USER command must be followed by a username

gotUser

protected abstract void gotUser()

tells the client that a USER command was successful

sendUser

protected abstract void sendUser()

tells the client to send a USER command

noPassGiven

protected abstract void noPassGiven()

tells the client that the PASS command must be followed by a password

login

protected abstract void login()

tells the client that the login was successful

loginFailed

protected abstract boolean loginFailed(int cnt)

tells the client that the login was unsuccessful and decides if the connection shall be closed

Parameters:: cnt - number of failed logins so far
Returns:: true - the connection to the client will be closed

sendPass

protected abstract void sendPass()

tells the client to send a PASS command

prompt

protected abstract void prompt()

tells the client that it can send a command

run

public void run()

This method handles the communication with the client.

Overrides:: run in class java.lang.Thread

Field Summary
`protected LoginServer`	`myServer` a reference to the LoginServer that has spawned this LoginServerThread
`protected java.io.PrintWriter`	`out` the output stream to the client

Constructor Summary
`LoginServerThread(LoginServer myServer, java.io.PrintWriter logStream, java.util.Hashtable passwd, java.net.Socket socket)` standard constructor

Method Summary
`protected abstract void`	`doubleLogin()` tells the client that this user is already logged on and the connection will be closed
`java.net.InetAddress`	`getClientIP()` returns the IP address of the client
`long`	`getID()` returns the ID of this LoginServerThread
`java.lang.String`	`getUsername()` returns the username of the user logged on
`protected abstract void`	`gotUser()` tells the client that a USER command was successful
`protected abstract void`	`invalidCommand()` tells the client that the given command was invalid
`protected void`	`log(java.lang.String message)` writes a message to the log stream
`protected abstract void`	`login()` tells the client that the login was successful
`protected abstract boolean`	`loginFailed(int cnt)` tells the client that the login was unsuccessful and decides if the connection shall be closed
`protected abstract void`	`noPassGiven()` tells the client that the PASS command must be followed by a password
`protected abstract void`	`noUserGiven()` tells the client that the USER command must be followed by a username
`protected abstract void`	`parseCommand(java.lang.String command, java.lang.String data)` This method handles non-standard client commands.
`protected abstract void`	`prompt()` tells the client that it can send a command
`void`	`run()` This method handles the communication with the client.
`protected abstract void`	`sendPass()` tells the client to send a PASS command
`protected abstract void`	`sendUser()` tells the client to send a USER command
`protected abstract void`	`sessionEnd()` tells the client that the connection will be closed
`protected abstract void`	`sessionStart()` tells the client that the connection is established
`protected abstract void`	`showHelp()` sends a list of supported commands to the client
`void`	`shutdown()` immediately closes connection to the client
`protected abstract boolean`	`validCommand(java.lang.String command)` checks whether a command sent from the client is allowed

de.cgarbs.net Class LoginServerThread

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