org.sadun.util
Class TelnetInputStream

java.lang.Object
  java.io.InputStream
      java.io.FilterInputStream
          org.sadun.util.TelnetInputStream

Direct Known Subclasses:

TelnetNVTChannel

public class TelnetInputStream

extends java.io.FilterInputStream

A stream to handle telnet-based communication.

The stream recognizes the standard TELNET command sequences (RFC854) in an input stream and allows for either batch or immediate handling.

Batch handling can be realized by retrieving the list of commands when the input is blocked, by using getCommands().

Immediate handling can be realized by registering a TelnetInputStream.TelnetCommandListener and responding to the command (to the appropriate output stream) with the result, and invoking #commandHandled(TelnetCommand) after the command has been properly handled.

TelnetInputStream.BasicNVTListener is a listener which automatically denies any option request, limiting the interaction capabilities to the Telnet NVT.

See also the class TelnetInputStreamConsumer for a wrapper which provides efficient consumption capabilities for machine-processing TELNET conversations.

Version:

0.2

Author:

Cristiano Sadun

Nested Class Summary

static class	TelnetInputStream.BasicNVTListener A standard TelnetInputStream.TelnetCommandListenerthat refuses any option and suggestions, limiting the functionality to the basic Telnet NVT (network virtual terminal) functionality.
class	TelnetInputStream.TelnetCommand A Telnet command, associated to a specific TelnetInputStream.
static interface	TelnetInputStream.TelnetCommandListener A listener to Telnet commands.

Field Summary

static int	AO The Telnet command code AO (245)
static int	AYT The Telnet command code IAC (246)
static int	BREAK The Telnet command code BREAK (243)
static int	DM The Telnet command code DM (242)
static int	DO The Telnet command code DO (253)
static int	DONT The Telnet command code DONT (254)
static int	EC The Telnet command code EC (247)
static int	EL The Telnet command code EL (248)
static int	GA The Telnet command code GA (249)
static int	IAC The Telnet command code IAC (255)
static int	IP The Telnet command code IP (244)
static int	NOP The Telnet command code NOP (241)
static int	SB The Telnet command code SB (250)
static int	SE The Telnet command code SE (240)
static int	WILL The Telnet command code WILL (251)
static int	WONT The Telnet command code WONT (252)

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

TelnetInputStream(java.io.InputStream in)
Create a telnet input stream over the given input stream.

Method Summary

void	commandHandled(TelnetInputStream.TelnetCommand command) Remove a command from the list of unhandled commands.
TelnetInputStream.TelnetCommand[]	getCommands() Return the list of commands encountered so far, and not yet handled.
java.io.PrintStream	getDebugStream() A Line mode helper.
int	read()
void	registerTelnetCommandListener(TelnetInputStream.TelnetCommandListener tcl) Register a listener to Telnet commands.
void	removeTelnetCommandListener(TelnetInputStream.TelnetCommandListener tcl) Remove a listener to Telnet commands.
void	setDebugStream(java.io.PrintStream debugStream)

Methods inherited from class java.io.FilterInputStream

available, close, mark, markSupported, read, read, reset, skip

Methods inherited from class java.lang.Object

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

Field Detail

IAC

public static final int IAC

The Telnet command code IAC (255)

See Also:

Constant Field Values

SE

public static final int SE

The Telnet command code SE (240)

See Also:

Constant Field Values

NOP

public static final int NOP

The Telnet command code NOP (241)

See Also:

Constant Field Values

DM

public static final int DM

The Telnet command code DM (242)

See Also:

Constant Field Values

BREAK

public static final int BREAK

The Telnet command code BREAK (243)

See Also:

Constant Field Values

IP

public static final int IP

The Telnet command code IP (244)

See Also:

Constant Field Values

AO

public static final int AO

The Telnet command code AO (245)

See Also:

Constant Field Values

AYT

public static final int AYT

The Telnet command code IAC (246)

See Also:

Constant Field Values

EC

public static final int EC

The Telnet command code EC (247)

See Also:

Constant Field Values

EL

public static final int EL

The Telnet command code EL (248)

See Also:

Constant Field Values

GA

public static final int GA

The Telnet command code GA (249)

See Also:

Constant Field Values

SB

public static final int SB

The Telnet command code SB (250)

See Also:

Constant Field Values

WILL

public static final int WILL

The Telnet command code WILL (251)

See Also:

Constant Field Values

WONT

public static final int WONT

The Telnet command code WONT (252)

See Also:

Constant Field Values

DO

public static final int DO

The Telnet command code DO (253)

See Also:

Constant Field Values

DONT

public static final int DONT

The Telnet command code DONT (254)

See Also:

Constant Field Values

Constructor Detail

TelnetInputStream

public TelnetInputStream(java.io.InputStream in)

Create a telnet input stream over the given input stream.

Method Detail

read

public int read()
         throws java.io.IOException

Throws:

java.io.IOException

getCommands

public TelnetInputStream.TelnetCommand[] getCommands()

Return the list of commands encountered so far, and not yet handled. (Handling is notified by invoking #commandHandled(TelnetCommand).

Returns:

the list of commands encountered so far, and not yet handled.

commandHandled

public void commandHandled(TelnetInputStream.TelnetCommand command)

Remove a command from the list of unhandled commands. This method is used to notify the stream that a Telnet command has been handled, and is typically invoked after either batch or immediate command processing.

Parameters:

command - the command that has been handled.

registerTelnetCommandListener

public void registerTelnetCommandListener(TelnetInputStream.TelnetCommandListener tcl)

Register a listener to Telnet commands.

Parameters:

tcl - the listener to register

removeTelnetCommandListener

public void removeTelnetCommandListener(TelnetInputStream.TelnetCommandListener tcl)

Remove a listener to Telnet commands.

Parameters:

tcl - the listener to remove

getDebugStream

public java.io.PrintStream getDebugStream()

A Line mode helper. Converts both CR LF and CR NUL into a new line, and strips it.

Returns:

a line, interpreted basing on CR LF and CR NUL.

Throws:

java.io.IOException - public String readLine() throws IOException { StringBuffer sb = null; int c0 = -1, c1 = -1; while ((c1 = read()) != -1) { if (sb == null) sb = new StringBuffer(); if ((c0 == '\r' && c1 == '\n') | // CRLF| (c0 == '\r' && c1 == 0)) // CR NUL break; sb.append((char) (c0 = c1)); } if (sb == null) return null; sb.deleteCharAt(sb.length() - 1); String result = sb.toString(); if (trimLinesEnabled) result = result.trim(); return result; } /** Return whether or not the line mode helper #readLine()will trim received lines.

setDebugStream

public void setDebugStream(java.io.PrintStream debugStream)