com.sptci.system
Class CommandExecutor

java.lang.Object
  com.sptci.system.CommandExecutor

public class CommandExecutor
extends Object

The class that is used to interact with the system. Provides methods to log user to the system and execute the password change command.

Modified version of class documented in informit.com.

Version:

$Id: CommandExecutor.java 3252 2007-05-12 19:12:31Z rakesh $

Author:

Rakesh Vidyadharan 2007-04-21

Field Summary

private TelnetClient	client The telnet client instance to use to communicate with the server.
private InputStream	in The InputStream for the telnet session.
private static Logger	logger The logger to use to log errors/messages to.
static String	LOGIN_PROMPT The name of the property that contains the login prompt sent back by telnet server when a connection attempt is made.
private PrintStream	out The OutputStream for the telnet session.
static String	PASSWORD_PROMPT The name of the property that contains the password prompt sent back by telnet server after a response is sent to the LOGIN_PROMPT "password"
(package private) int	port The port on which to connect to the server.
static String	PORT The name of the property that contains the port on which a telnet session will be established.
static String	PROMPT The name of the property that contains the shell prompt character used by the system.
(package private) Properties	properties The properties object that contains the configured properties for this instance.
static String	PROPERTY_FILE The name of the system property that points to the properties file used to configure this instance.
(package private) String	server The server to log on to affect the change in password.
static String	SERVER The name of the property that contains the hostname of the server to which a telnet session will be initiated.
(package private) String	user The user who is trying to change his password.

Constructor Summary

CommandExecutor()
Create a new instance of the class;

Method Summary

void	connect(String password) Connect to the server via telnet and log the user to the system.
void	connect(String user, String password) Connect to the server via telnet and log the user to the system.
void	disconnect() Disconnect from the telnet session.
private String	execute(String command) Send a command for execution to the telnet session.
String	getUser() Returns user.
void	password(String password, String newpassword) Change the user's password.
private String	readLoginResponse() Read the response from the server after a login attempt.
private String	readPasswordResponse(String success, String error, String message) Read the response from the server after the current password has been entered during a password change request.
private String	readUntil(String pattern) Read the response from the server until the specified pattern is found.
void	setUser(String user) Set user.
private void	write(String response) Write a response to the telnet OutputStream.

Methods inherited from class java.lang.Object

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

Field Detail

logger

private static final Logger logger

The logger to use to log errors/messages to.

PROPERTY_FILE

public static final String PROPERTY_FILE

The name of the system property that points to the properties file used to configure this instance. "password.properties.file"

See Also:

Constant Field Values

SERVER

public static final String SERVER

The name of the property that contains the hostname of the server to which a telnet session will be initiated. "server"

See Also:

Constant Field Values

PORT

public static final String PORT

The name of the property that contains the port on which a telnet session will be established. This propery is optional. By default a connection to the standard telnet port 23 will be attempted. "port"

See Also:

Constant Field Values

LOGIN_PROMPT

public static final String LOGIN_PROMPT

The name of the property that contains the login prompt sent back by telnet server when a connection attempt is made. "login"

See Also:

Constant Field Values

PASSWORD_PROMPT

public static final String PASSWORD_PROMPT

The name of the property that contains the password prompt sent back by telnet server after a response is sent to the LOGIN_PROMPT "password"

See Also:

Constant Field Values

PROMPT

public static final String PROMPT

The name of the property that contains the shell prompt character used by the system.

Note: This of course depends upon the shell used by the user and the user's settings.

"prompt"

See Also:

Constant Field Values

server

final String server

The server to log on to affect the change in password.

port

final int port

The port on which to connect to the server.

user

String user

The user who is trying to change his password.

client

private TelnetClient client

The telnet client instance to use to communicate with the server.

properties

final Properties properties

The properties object that contains the configured properties for this instance.

in

private InputStream in

The InputStream for the telnet session.

out

private PrintStream out

The OutputStream for the telnet session.

Constructor Detail

CommandExecutor

public CommandExecutor()
                throws RuntimeException

Create a new instance of the class;

Throws:

RuntimeException - If errors are encountered while initialising the instance from the PROPERTY_FILE file.

Method Detail

connect

public void connect(String password)
             throws SocketException,
                    IOException,
                    AuthenticationFailedException

Connect to the server via telnet and log the user to the system. This method assumes that caller has either invoked setUser(java.lang.String) or connect( String, String ) prior to calling this method.

Throws:

SocketException - If the socket timeout could not be set.

IOException - If the socket could not be opened. In most cases you will only want to catch IOException since SocketException is derived from it.

AuthenticationFailedException - If the login attempt failed due to username or password error.

See Also:

connect( String, String )

connect

public void connect(String user,
                    String password)
             throws SocketException,
                    IOException,
                    AuthenticationFailedException

Connect to the server via telnet and log the user to the system.

Throws:

SocketException - If the socket timeout could not be set.

IOException - If the socket could not be opened. In most cases you will only want to catch IOException since SocketException is derived from it.

AuthenticationFailedException - If the login attempt failed due to username or password error.

See Also:

readUntil(java.lang.String), write(java.lang.String), readLoginResponse()

password

public void password(String password,
                     String newpassword)
              throws IOException,
                     PasswordException

Change the user's password.

Parameters:

password - The current password of the user.

newpassword - The new password to set.

Throws:

IOException - If the socket could not be opened. In most cases you will only want to catch IOException since SocketException is derived from it.

PasswordException - If the current or new password are incorrect or insufficient

disconnect

public void disconnect()

Disconnect from the telnet session.

readUntil

private String readUntil(String pattern)
                  throws IOException

Read the response from the server until the specified pattern is found.

Parameters:

pattern - The pattern until which the response from the server is to be read

Throws:

IOException - If errors are encountered while reading/writing to the socket streams.

readLoginResponse

private String readLoginResponse()
                          throws IOException,
                                 AuthenticationFailedException

Read the response from the server after a login attempt. Handle either a successful login or a failed login. Failed logins are indicated when the system responds with a fresh login prompt along with an error message.

Throws:

IOException - If errors are encountered while reading/writing to the socket streams.

AuthenticationFailedException - If the login attempt failed due to username or password error.

readPasswordResponse

private String readPasswordResponse(String success,
                                    String error,
                                    String message)
                             throws IOException,
                                    PasswordException

Read the response from the server after the current password has been entered during a password change request.

Parameters:

success - The pattern that indicates a successful entry

error - The pattern that indicates an error

message - The message to use in PasswordException.

Throws:

IOException - If errors are encountered while reading/writing to the socket streams.

PasswordException - If the current password specified is incorrect.

write

private void write(String response)
            throws IOException

Write a response to the telnet OutputStream.

Parameters:

response - The response that is to be written to the stream.

Throws:

IOException - If errors are encountered while reading/writing to the socket streams.

execute

private String execute(String command)
                throws IOException

Send a command for execution to the telnet session.

Parameters:

command - The command that is to be executed.

Throws:

IOException - If errors are encountered while sending the command for execution.

See Also:

write(java.lang.String), readUntil(java.lang.String)

getUser

public String getUser()

Returns user.

Returns:

The value/reference of/to user.

setUser

public void setUser(String user)

Set user.

Parameters:

user - The value to set.