com.jscape.inet.telnet
Class Telnet

java.lang.Object
  com.jscape.inet.telnet.Telnet

All Implemented Interfaces:

java.io.Serializable

public class Telnet
extends java.lang.Object
implements java.io.Serializable

Implements the basic functionality of a Telnet client as defined in RFC 854. Upon establishing a connection the Telnet server may attempt to perform option negotiation (see RFC 855). Any option negotiation options exchanged must be handled prior to receiving a login or shell prompt.

To handle option negotiation you must add a TelnetListener to the Telnet instance and overload the doOption, dontOption, willOption and wontOption methods.

Once option negotiation has completed sucessfully a separate thread is spawned that reads data sent by the Telnet server. You can capture this data by overloading the dataReceived method in the TelnetListener interface or TelnetAdapter class.

Example:

 public class TelnetExample extends TelnetAdapter {

      private Telnet telnet = null;
      private OutputStream output = null;
      private static BufferedReader reader = null;
      private boolean connected = false;
      private String hostname = "10.0.0.1";

      public TelnetExample() throws IOException, TelnetException {

              // create new Telnet instance
              telnet = new Telnet(hostname);

              // register this class as TelnetListener
              telnet.addTelnetListener(this);

              // establish Telnet connection
              telnet.connect();
              connected = true;

              // get output stream
              output = telnet.getOutputStream();

              // sends all data entered at console to Telnet server
              String input = null;
              while ((input = reader.readLine()) != null) {
                      if (connected) {
                              ((TelnetOutputStream) output).println(input);
             } else {
                              break;
             }
         }
     }

      // Invoked when Telnet socked is connected.
      public void connected(TelnetConnectedEvent event) {
              System.out.println("Connected");
     }

      // Invoked when Telnet socket is disconnected. Disconnect can
      public void disconnected(TelnetDisconnectedEvent event) {
              connected = false;
              System.out.print("Disconnected.  Press enter key to quit.");
     }

      // Invoked when Telnet server requests that the Telnet client begin performing specified TelnetOption.
      public void doOption(DoOptionEvent event) {
              // refuse any options requested by Telnet server
              telnet.sendWontOption(event.getOption());
     }

      // Invoked when Telnet server offers to begin performing specified TelnetOption.
      public void willOption(WillOptionEvent event) {
              // refuse any options offered by Telnet server
              telnet.sendDontOption(event.getOption());
     }

      // Invoked when data is received from Telnet server.
      public void dataReceived(TelnetDataReceivedEvent event) {
              // print data recevied from Telnet server to console
              System.out.print(event.getData());
     }

      // starts console program
      public static void main(String[] args) {
              try {
                      // create BufferedReader to read data from console
                      reader = new BufferedReader(new InputStreamReader(System.in));

                      // create new TelnetExample instance
                      TelnetExample example = new TelnetExample();

         } catch (Exception e) {
                      e.printStackTrace(System.out);
         }
     }

 }

 

See Also:

Serialized Form

Nested Class Summary

class	Telnet.ByteDecoder Byte Decoder
class	Telnet.DefaultDecoder Default Decoder
class	Telnet.EUCKoreanDecoder EUC Korean Decoder
class	Telnet.UTF8Decoder UTF8 Decoder

Field Summary

static java.lang.String[]	COMMAND_MAP This field can be used to map command codes to their String representation.
static int	TC_AO Telnet command : Abort output
static int	TC_AYT Telnet command : Are You There
static int	TC_BRK Telnet command : Break. NVT character BRK.
static int	TC_DM Telnet command : Data Mark. The data stream portion of a Synch.
static int	TC_DO Telnet command : DO. Indicates the request that the other party perform, or confirmation that you are expecting the other party to perform, the indicated option.
static int	TC_DONT Telnet command : DON'T. Indicates the demand that the other party stop performing, or confirmation that you are no longer expecting the other party to perform, the indicated option.
static int	TC_GA Telnet command : Go ahead
static int	TC_IP Telnet command : Interrupt Process.
static int	TC_NOP Telnet command : No operation.
static int	TC_SB Telnet command : Subnegotiation. Indicates that what follows is subnegotiation of the indicated option.
static int	TC_SE Telnet command : End of subnegotiation parameters.
static int	TC_WILL Telnet command : WILL. Indicates the desire to begin performing, or confirmation that you are now performing, the indicated option.
static int	TC_WONT Telnet command : WON'T. Indicates the refusal to perform, or continue performing, the indicated option.
static int	TSC_BEL Telnet special character : BELL. Produces an audible or visible signal (which does NOT move the print head).
static int	TSC_BS Telnet special character : Back Space. Moves the print head one character position towards the left margin.
static int	TSC_CR Telnet special character : Carriage Return. Moves the printer to the left margin of the current line.
static int	TSC_EC Telnet special character : Erase character
static int	TSC_EL Telnet special character : Erase line
static int	TSC_FF Telnet special character : Form Feed. Moves the printer to the top of the next page, keeping the same horizontal position.
static int	TSC_HT Telnet special character : Horizontal Tab. Moves the printer to the next horizontal tab stop.
static int	TSC_IAC Telnet escape charater : Interpret as Command
static int	TSC_LF Telnet special character : Line Feed. Moves the printer to the next print line, keeping the same horizontal position.
static int	TSC_NULL Telnet special character : No operation
static int	TSC_VT Telnet special character : Vertical Tab. Moves the printer to the next vertical tab stop.

Constructor Summary

Telnet(java.lang.String hostname)
Constructs Telnet object for connection to specified host.

Telnet(java.lang.String host, int port)
Constructs Telnet object.

Method Summary

void	addTelnetListener(TelnetListener listener) Add telnet event listener.
void	clearProxySettings() Clears proxy server values.
void	connect() Connect the client socket to host and port specified by contructor or setHostname(java.lang.String), setPort(int) methods.
void	disconnect() Disconnects and releases all associated resources.
java.lang.String	getCharacterSet() Gets the character set used when reading data from Telnet server.
java.lang.String	getCommandName(int command) Gets name of command based on corresponding command.
boolean	getDebug() Gets debugging state.
java.io.PrintStream	getDebugStream() Gets PrintStream used in reporting debug statements.
java.lang.String	getHostname() Return server hostname.
java.io.InputStream	getInputStream() Returns input stream associated with current Telnet connection.
java.io.OutputStream	getOutputStream() Returns output stream associated with current telnet connection.
int	getPort() Return server port.
java.io.Reader	getReader() Returns Reader object for reading from the server.
int	getTimeout() Gets the timeout for opening connection to Telnet server.
java.io.Writer	getWriter() Returns Writer object for writing to server.
void	removeTelnetListener(TelnetListener listener) Remove telnet event listener.
void	sendCommand(int command) Sends telnet command.
void	sendCommand(int command, int parameter) Sends telnet command with specified parameter.
void	sendDontOption(TelnetOption opt) Sends Telnet option to server with Telnet DONT OPTION (refuse request to use option) command
void	sendDoOption(TelnetOption opt) Sends Telnet option to server with Telnet DO OPTION (request to use option) command
void	sendOptionSubnegotiation(TelnetOption opt) Initiate subnegotiation for option.
void	sendWillOption(TelnetOption opt) Sends Telnet option to server with Telnet WILL OPTION (accept offer to use option) command.
void	sendWontOption(TelnetOption opt) Sends Telnet option to server with Telnet WONT OPTION (refuse offer to use option) command.
void	setCharacterSet(java.lang.String characterSet) Sets character set used when reading data from telnet server
void	setDebug(boolean debug) Enable debugging output to debugging stream.
void	setDebugStream(java.io.PrintStream debugStream) Sets PrintStream used in reporting debug statements.
void	setHostname(java.lang.String hostname) Set server hostname.
void	setPort(int port) Set server port.
void	setProxyAuthentication(java.lang.String proxyUsername, java.lang.String proxyPassword) Sets the username and password to use when for authentication with proxy server.
void	setProxyHost(java.lang.String proxyHostname, int proxyPort) Sets the proxy hostname and port for this connection.
void	setProxyType(java.lang.String proxyType) Sets the proxy type will be used for this connection.
void	setTimeout(int timeout) Sets the timeout for opening connection to Telnet server.

Methods inherited from class java.lang.Object

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

Field Detail

TSC_NULL

public static final int TSC_NULL

Telnet special character : No operation

See Also:

Constant Field Values

TSC_BEL

public static final int TSC_BEL

Telnet special character : BELL.
Produces an audible or visible signal (which does NOT move the print head).

See Also:

Constant Field Values

TSC_BS

public static final int TSC_BS

Telnet special character : Back Space.
Moves the print head one character position towards the left margin.

See Also:

Constant Field Values

TSC_HT

public static final int TSC_HT

Telnet special character : Horizontal Tab.
Moves the printer to the next horizontal tab stop. It remains unspecified how either party determines or establishes where such tab stops are located.

See Also:

Constant Field Values

TSC_LF

public static final int TSC_LF

Telnet special character : Line Feed.
Moves the printer to the next print line, keeping the same horizontal position.

See Also:

Constant Field Values

TSC_VT

public static final int TSC_VT

Telnet special character : Vertical Tab.
Moves the printer to the next vertical tab stop. It remains unspecified how either party determines or establishes where such tab stops are located.

See Also:

Constant Field Values

TSC_FF

public static final int TSC_FF

Telnet special character : Form Feed.
Moves the printer to the top of the next page, keeping the same horizontal position.

See Also:

Constant Field Values

TSC_CR

public static final int TSC_CR

Telnet special character : Carriage Return.
Moves the printer to the left margin of the current line.

See Also:

Constant Field Values

TC_SE

public static final int TC_SE

Telnet command : End of subnegotiation parameters.

See Also:

Constant Field Values

TC_NOP

public static final int TC_NOP

Telnet command : No operation.

See Also:

Constant Field Values

TC_DM

public static final int TC_DM

Telnet command : Data Mark.
The data stream portion of a Synch. This should always be accompanied by a TCP Urgent notification.

See Also:

Constant Field Values

TC_BRK

public static final int TC_BRK

Telnet command : Break.
NVT character BRK.

See Also:

Constant Field Values

TC_IP

public static final int TC_IP

Telnet command : Interrupt Process.

See Also:

Constant Field Values

TC_AO

public static final int TC_AO

Telnet command : Abort output

See Also:

Constant Field Values

TC_AYT

public static final int TC_AYT

Telnet command : Are You There

See Also:

Constant Field Values

TSC_EC

public static final int TSC_EC

Telnet special character : Erase character

See Also:

Constant Field Values

TSC_EL

public static final int TSC_EL

Telnet special character : Erase line

See Also:

Constant Field Values

TC_GA

public static final int TC_GA

Telnet command : Go ahead

See Also:

Constant Field Values

TC_SB

public static final int TC_SB

Telnet command : Subnegotiation.
Indicates that what follows is subnegotiation of the indicated option.

See Also:

Constant Field Values

TC_WILL

public static final int TC_WILL

Telnet command : WILL.
Indicates the desire to begin performing, or confirmation that you are now performing, the indicated option.

See Also:

Constant Field Values

TC_WONT

public static final int TC_WONT

Telnet command : WON'T.
Indicates the refusal to perform, or continue performing, the indicated option.

See Also:

Constant Field Values

TC_DO

public static final int TC_DO

Telnet command : DO.
Indicates the request that the other party perform, or confirmation that you are expecting the other party to perform, the indicated option.

See Also:

Constant Field Values

TC_DONT

public static final int TC_DONT

Telnet command : DON'T.
Indicates the demand that the other party stop performing, or confirmation that you are no longer expecting the other party to perform, the indicated option.

See Also:

Constant Field Values

TSC_IAC

public static final int TSC_IAC

Telnet escape charater : Interpret as Command

See Also:

Constant Field Values

COMMAND_MAP

public static final java.lang.String[] COMMAND_MAP

This field can be used to map command codes to their String representation.

Constructor Detail

Telnet

public Telnet(java.lang.String hostname)

Constructs Telnet object for connection to specified host.

Parameters:

hostname - the hostname or IP address of the Telnet server

Telnet

public Telnet(java.lang.String host,
              int port)

Constructs Telnet object.

Parameters:

host - the hostname or IP address of the Telnet server

port - the port of the Telnet server

Method Detail

connect

public void connect()
             throws TelnetException

Connect the client socket to host and port specified by contructor or setHostname(java.lang.String), setPort(int) methods.

Throws:

TelnetException

disconnect

public void disconnect()

Disconnects and releases all associated resources.

setHostname

public void setHostname(java.lang.String hostname)

Set server hostname.

Parameters:

hostname - the hostname or IP address of the Telnet server

getHostname

public java.lang.String getHostname()

Return server hostname.

Returns:

the hostname or IP address of the Telnet server

setPort

public void setPort(int port)

Set server port.

Parameters:

port - the port of the Telnet server

getPort

public int getPort()

Return server port.

Returns:

the port of the Telnet server

setProxyAuthentication

public void setProxyAuthentication(java.lang.String proxyUsername,
                                   java.lang.String proxyPassword)

Sets the username and password to use when for authentication with proxy server. To clear these settings invoke the #clearProxySettings method.

Parameters:

proxyUsername - the proxy username

proxyPassword - the proxy password

See Also:

clearProxySettings()

setProxyHost

public void setProxyHost(java.lang.String proxyHostname,
                         int proxyPort)

Sets the proxy hostname and port for this connection. To clear these settings invoke the #clearProxySettings method.

Parameters:

proxyHostname - the hostname or ip address of the proxy server

proxyPort - the port of the proxy server

See Also:

clearProxySettings()

setProxyType

public void setProxyType(java.lang.String proxyType)

Sets the proxy type will be used for this connection.

Parameters:

proxyType - The proxy type. Valid values: HTTP, SOCKS5

clearProxySettings

public void clearProxySettings()

Clears proxy server values.

addTelnetListener

public void addTelnetListener(TelnetListener listener)

Add telnet event listener.

Parameters:

listener - a TelnetListener

See Also:

TelnetListener

removeTelnetListener

public void removeTelnetListener(TelnetListener listener)

Remove telnet event listener.

Parameters:

listener - a TelnetListener

See Also:

TelnetListener

sendCommand

public void sendCommand(int command)

Sends telnet command.

Parameters:

command - the command to send

sendCommand

public void sendCommand(int command,
                        int parameter)

Sends telnet command with specified parameter.

Parameters:

command - the command to send

parameter - the parameter to send

getInputStream

public java.io.InputStream getInputStream()

Returns input stream associated with current Telnet connection. Telnet commands, special and control characters are filtered out of this stream.

Returns:

an InputStream

getOutputStream

public java.io.OutputStream getOutputStream()

Returns output stream associated with current telnet connection. Commands, special and control characters should be written only using Telnet class methods, rather than directly writing to this stream.

Returns:

an OutputStream

getReader

public java.io.Reader getReader()

Returns Reader object for reading from the server.

Returns:

a Reader

getWriter

public java.io.Writer getWriter()

Returns Writer object for writing to server.

Returns:

a Writer

sendOptionSubnegotiation

public void sendOptionSubnegotiation(TelnetOption opt)

Initiate subnegotiation for option.

Parameters:

opt - a TelnetOption

See Also:

TelnetOption

getCommandName

public java.lang.String getCommandName(int command)

Gets name of command based on corresponding command.

Parameters:

command - the command code

Returns:

the name of command code or null if not found

sendWillOption

public void sendWillOption(TelnetOption opt)

Sends Telnet option to server with Telnet WILL OPTION (accept offer to use option) command.

Parameters:

opt - the option to send

sendWontOption

public void sendWontOption(TelnetOption opt)

Sends Telnet option to server with Telnet WONT OPTION (refuse offer to use option) command.

Parameters:

opt - the option to send

sendDoOption

public void sendDoOption(TelnetOption opt)

Sends Telnet option to server with Telnet DO OPTION (request to use option) command

Parameters:

opt - the option to send

sendDontOption

public void sendDontOption(TelnetOption opt)

Sends Telnet option to server with Telnet DONT OPTION (refuse request to use option) command

Parameters:

opt - the option to send

setDebug

public void setDebug(boolean debug)

Enable debugging output to debugging stream.

Parameters:

debug - true if debugging enabled, false otherwise

See Also:

setDebugStream(java.io.PrintStream)

getDebug

public boolean getDebug()

Gets debugging state.

Returns:

true if debugging is enabled

getDebugStream

public java.io.PrintStream getDebugStream()

Gets PrintStream used in reporting debug statements. Default PrintStream is System.out

Returns:

the PrintStream used in reporting debug statements

See Also:

PrintStream

setTimeout

public void setTimeout(int timeout)

Sets the timeout for opening connection to Telnet server.

Parameters:

timeout - the timeout in milliseconds

getTimeout

public int getTimeout()

Gets the timeout for opening connection to Telnet server.

Returns:

timeout in milliseconds

setCharacterSet

public void setCharacterSet(java.lang.String characterSet)

Sets character set used when reading data from telnet server

Parameters:

characterSet - the character set

getCharacterSet

public java.lang.String getCharacterSet()

Gets the character set used when reading data from Telnet server. Default is null, using the default system character set.

Returns:

the character set or null

setDebugStream

public void setDebugStream(java.io.PrintStream debugStream)

Sets PrintStream used in reporting debug statements. Default PrintStream is System.out

Parameters:

debugStream - the PrintStream to send debug statements to

See Also:

PrintStream