java.lang.Object
- java.lang.Thread
- - org.eclipse.remote.telnet.core.TelnetProtocol

All Implemented Interfaces:

Runnable
```
public class TelnetProtocol
extends Thread
```
This class encapsulates a TELNET connection to a remote server. It processes incoming TELNET protocol data and generates outbound TELNET protocol data. It also manages two sets of TelnetOption objects: one for the local endpoint and one for the remote endpoint.
IMPORTANT: Understanding this code requires understanding the TELNET protocol and TELNET option processing, as defined in the RFCs listed below.

See Also:

RFC 854, RFC 855, RFC 856, RFC 857, RFC 858, RFC 859, RFC 860, RFC 861, RFC 1091, RFC 1096, RFC 1073, RFC 1079, RFC 1143, RFC 1572

Nested Class Summary
- Nested classes/interfaces inherited from class java.lang.Thread
  Thread.State, Thread.UncaughtExceptionHandler

Field Summary

Fields
Modifier and Type	Field	Description
`protected static int`	`BUFFER_SIZE`	Size of buffer for processing data received from remote endpoint.
`protected OutputStream`	`clientOutputStream`	This field holds a reference to an `OutputStream` object used to send data to the client.
`protected int`	`height`	This field holds the height of the Terminal screen in rows.
`protected boolean`	`ignoreSubnegotiation`	This field is true if an error occurs while processing a subnegotiation command.
`protected ReadableByteChannel`	`inputChannel`	This field holds a reference to an `ReadableByteChannel` object used to receive data from the remote endpoint.
`protected boolean`	`localEcho`	UNDER CONSTRUCTION
`protected org.eclipse.remote.telnet.core.TelnetOption[]`	`localOptions`	An array of TelnetOption objects representing the local endpoint's TELNET options.
`protected int`	`nextSubnegotiationByteIndex`	This field holds the index into array `receivedSubnegotiation` of the next unused byte.
`protected byte[]`	`processedBytes`	Holds incoming network data after the TELNET protocol bytes have been processed and removed.
`protected StringBuffer`	`processedStringBuffer`	This field holds a StringBuffer containing text recently received from the remote endpoint (after all TELNET protocol bytes have been processed and removed).
`protected ByteBuffer`	`rawBytes`	Holds raw bytes received from the remote endpoint, prior to any TELNET protocol processing.
`protected byte[]`	`receivedSubnegotiation`	An array of bytes that holds the TELNET subnegotiation command most recently received from the remote endpoint.
`protected boolean`	`remoteIsTelnetServer`	This field is true if the remote endpoint is a TELNET server, false if not.
`protected org.eclipse.remote.telnet.core.TelnetOption[]`	`remoteOptions`	An array of TelnetOption objects representing the remote endpoint's TELNET options.
`protected OutputStream`	`serverOutputStream`	This field holds a reference to an `OutputStream` object used to send data to the remote endpoint.
`protected TelnetCommandShell`	`shell`	This field holds a reference to the `TelnetCommandShell`.
`protected Socket`	`socket`	This method holds the Socket object for the TELNET connection.
`protected static int`	`STATE_DO_RECEIVED`	TELNET connection state: Last byte processed was DO code.
`protected static int`	`STATE_DONT_RECEIVED`	TELNET connection state: Last byte processed was DONT code.
`protected static int`	`STATE_IAC_RECEIVED`	TELNET connection state: Last byte processed was IAC code.
`protected static int`	`STATE_INITIAL`	TELNET connection state: Initial state.
`protected static int`	`STATE_RECEIVING_SUBNEGOTIATION`	TELNET connection state: Currently receiving sub-negotiation data.
`protected static int`	`STATE_SUBNEGOTIATION_STARTED`	TELNET connection state: Last byte processed was SB.
`protected static int`	`STATE_WILL_RECEIVED`	TELNET connection state: Last byte processed was WILL code.
`protected static int`	`STATE_WONT_RECEIVED`	TELNET connection state: Last byte processed was WONT code.
`static byte`	`TELNET_AO`	Command code: Abort Output.
`static byte`	`TELNET_AYT`	Command code: Are You There.
`static byte`	`TELNET_BREAK`	Command code: Break.
`static byte`	`TELNET_DM`	Command code: Data Mark.
`static byte`	`TELNET_DO`	Command code: Do.
`static byte`	`TELNET_DONT`	Command code: Don't.
`static byte`	`TELNET_EC`	Command code: Erase Character.
`static byte`	`TELNET_EL`	Command code: Erase Line.
`static byte`	`TELNET_GA`	Command code: Go Ahead.
`static byte`	`TELNET_IAC`	Command code: Interpret As Command.
`static byte`	`TELNET_IP`	Command code: Interrupt Process.
`static byte`	`TELNET_IS`	Command code: IS.
`static byte`	`TELNET_NOP`	Command code: No-op.
`static byte`	`TELNET_OPTION_ECHO`	Option code: Echo option.
`static byte`	`TELNET_OPTION_NAWS`	Option code: Negotitate About Window Size (NAWS)
`static byte`	`TELNET_OPTION_SUPPRESS_GA`	Option code: Suppress Go Ahead option.
`static byte`	`TELNET_OPTION_TERMINAL_TYPE`	Option code: Terminal Type
`static byte`	`TELNET_OPTION_TRANSMIT_BINARY`	Option code: Transmit Binary option.
`static byte`	`TELNET_SB`	Command code: Subnegotiation Begin.
`static byte`	`TELNET_SE`	Command code: Subnegotiation End.
`static byte`	`TELNET_SEND`	Command code: SEND.
`static byte`	`TELNET_WILL`	Command code: Will.
`static byte`	`TELNET_WONT`	Command code: Won't.
`protected int`	`telnetState`	Holds the current state of the TELNET protocol processor.
`protected int`	`width`	This field holds the width of the Terminal screen in columns.

Fields inherited from class java.lang.Thread
MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors
Constructor	Description
`TelnetProtocol(Socket socket, TelnetCommandShell shell)`	This constructor just initializes some internal object state from its arguments.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`OutputStream`	`getOutputStream()`
`protected void`	`initializeOptions()`	This method initializes the localOptions[] and remoteOptions[] arrays so that they contain references to TelnetOption objects representing our desired state for each option.
`boolean`	`isConnected()`	Returns true if the TCP connection represented by this object is connected, false otherwise.
`boolean`	`isRemoteTelnetServer()`	Returns true if the TCP connection represented by this object is connected and the remote endpoint is a TELNET server, false otherwise.
`boolean`	`localEcho()`	Returns true if local echoing is enabled for this TCP connection, false otherwise.
`protected int`	`processTelnetProtocol(int count)`	Process TELNET protocol data contained in the first count bytes of rawBytes.
`void`	`run()`	This method runs in its own thread.
`void`	`setClientOutputStream(OutputStream stream)`
`void`	`setTerminalSize(int newWidth, int newHeight)`	This method sets the terminal width and height to the supplied values.
`protected void`	`telnetServerDetected()`	This method is called whenever we receive a valid TELNET protocol command from the remote endpoint.

Methods inherited from class java.lang.Thread
activeCount, checkAccess, clone, countStackFrames, currentThread, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, onSpinWait, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, suspend, toString, yield

Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - STATE_INITIAL
```
protected static final int STATE_INITIAL
```
    TELNET connection state: Initial state.
    
    See Also:
    
    Constant Field Values
  - STATE_IAC_RECEIVED
```
protected static final int STATE_IAC_RECEIVED
```
    TELNET connection state: Last byte processed was IAC code. code.
    
    See Also:
    
    Constant Field Values
  - STATE_WILL_RECEIVED
```
protected static final int STATE_WILL_RECEIVED
```
    TELNET connection state: Last byte processed was WILL code. code.
    
    See Also:
    
    Constant Field Values
  - STATE_WONT_RECEIVED
```
protected static final int STATE_WONT_RECEIVED
```
    TELNET connection state: Last byte processed was WONT code.
    
    See Also:
    
    Constant Field Values
  - STATE_DO_RECEIVED
```
protected static final int STATE_DO_RECEIVED
```
    TELNET connection state: Last byte processed was DO code.
    
    See Also:
    
    Constant Field Values
  - STATE_DONT_RECEIVED
```
protected static final int STATE_DONT_RECEIVED
```
    TELNET connection state: Last byte processed was DONT code.
    
    See Also:
    
    Constant Field Values
  - STATE_SUBNEGOTIATION_STARTED
```
protected static final int STATE_SUBNEGOTIATION_STARTED
```
    TELNET connection state: Last byte processed was SB.
    
    See Also:
    
    Constant Field Values
  - STATE_RECEIVING_SUBNEGOTIATION
```
protected static final int STATE_RECEIVING_SUBNEGOTIATION
```
    TELNET connection state: Currently receiving sub-negotiation data.
    
    See Also:
    
    Constant Field Values
  - BUFFER_SIZE
```
protected static final int BUFFER_SIZE
```
    Size of buffer for processing data received from remote endpoint.
    
    See Also:
    
    Constant Field Values
  - rawBytes
```
protected ByteBuffer rawBytes
```
    Holds raw bytes received from the remote endpoint, prior to any TELNET protocol processing.
  - processedBytes
```
protected byte[] processedBytes
```
    Holds incoming network data after the TELNET protocol bytes have been processed and removed.
  - processedStringBuffer
```
protected StringBuffer processedStringBuffer
```
    This field holds a StringBuffer containing text recently received from the remote endpoint (after all TELNET protocol bytes have been processed and removed).
  - telnetState
```
protected int telnetState
```
    Holds the current state of the TELNET protocol processor.
  - remoteIsTelnetServer
```
protected boolean remoteIsTelnetServer
```
    This field is true if the remote endpoint is a TELNET server, false if not. We set this to true if and only if the remote endpoint sends recognizable TELNET protocol data. We do not assume that the remote endpoint is a TELNET server just because it is listening on port 23. This allows us to successfully connect to a TELNET server listening on a port other than 23.
    When this field first changes from false to true, we send all WILL or DO commands to the remote endpoint.
    
    See Also:
    
    telnetServerDetected()
  - localOptions
```
protected org.eclipse.remote.telnet.core.TelnetOption[] localOptions
```
    An array of TelnetOption objects representing the local endpoint's TELNET options. The array is indexed by the numeric TELNET option code.
  - remoteOptions
```
protected org.eclipse.remote.telnet.core.TelnetOption[] remoteOptions
```
    An array of TelnetOption objects representing the remote endpoint's TELNET options. The array is indexed by the numeric TELNET option code.
  - receivedSubnegotiation
```
protected byte[] receivedSubnegotiation
```
    An array of bytes that holds the TELNET subnegotiation command most recently received from the remote endpoint. This array does _not_ include the leading IAC SB bytes, nor does it include the trailing IAC SE bytes. The first byte of this array is always a TELNET option code.
  - nextSubnegotiationByteIndex
```
protected int nextSubnegotiationByteIndex
```
    This field holds the index into array receivedSubnegotiation of the next unused byte. This is used by method processTelnetProtocol(int) when the state machine is in states STATE_SUBNEGOTIATION_STARTED and STATE_RECEIVING_SUBNEGOTIATION.
  - ignoreSubnegotiation
```
protected boolean ignoreSubnegotiation
```
    This field is true if an error occurs while processing a subnegotiation command.
    
    See Also:
    
    processTelnetProtocol(int)
  - width
```
protected int width
```
    This field holds the width of the Terminal screen in columns.
  - height
```
protected int height
```
    This field holds the height of the Terminal screen in rows.
  - shell
```
protected TelnetCommandShell shell
```
    This field holds a reference to the TelnetCommandShell.
  - socket
```
protected Socket socket
```
    This method holds the Socket object for the TELNET connection.
  - inputChannel
```
protected ReadableByteChannel inputChannel
```
    This field holds a reference to an ReadableByteChannel object used to receive data from the remote endpoint.
  - serverOutputStream
```
protected OutputStream serverOutputStream
```
    This field holds a reference to an OutputStream object used to send data to the remote endpoint.
  - clientOutputStream
```
protected OutputStream clientOutputStream
```
    This field holds a reference to an OutputStream object used to send data to the client.
  - localEcho
```
protected boolean localEcho
```
    UNDER CONSTRUCTION
  - TELNET_SE
```
public static final byte TELNET_SE
```
    Command code: Subnegotiation End.
    
    See Also:
    
    Constant Field Values
  - TELNET_NOP
```
public static final byte TELNET_NOP
```
    Command code: No-op.
    
    See Also:
    
    Constant Field Values
  - TELNET_DM
```
public static final byte TELNET_DM
```
    Command code: Data Mark.
    
    See Also:
    
    Constant Field Values
  - TELNET_BREAK
```
public static final byte TELNET_BREAK
```
    Command code: Break.
    
    See Also:
    
    Constant Field Values
  - TELNET_IP
```
public static final byte TELNET_IP
```
    Command code: Interrupt Process.
    
    See Also:
    
    Constant Field Values
  - TELNET_AO
```
public static final byte TELNET_AO
```
    Command code: Abort Output.
    
    See Also:
    
    Constant Field Values
  - TELNET_AYT
```
public static final byte TELNET_AYT
```
    Command code: Are You There.
    
    See Also:
    
    Constant Field Values
  - TELNET_EC
```
public static final byte TELNET_EC
```
    Command code: Erase Character.
    
    See Also:
    
    Constant Field Values
  - TELNET_EL
```
public static final byte TELNET_EL
```
    Command code: Erase Line.
    
    See Also:
    
    Constant Field Values
  - TELNET_GA
```
public static final byte TELNET_GA
```
    Command code: Go Ahead.
    
    See Also:
    
    Constant Field Values
  - TELNET_SB
```
public static final byte TELNET_SB
```
    Command code: Subnegotiation Begin.
    
    See Also:
    
    Constant Field Values
  - TELNET_WILL
```
public static final byte TELNET_WILL
```
    Command code: Will.
    
    See Also:
    
    Constant Field Values
  - TELNET_WONT
```
public static final byte TELNET_WONT
```
    Command code: Won't.
    
    See Also:
    
    Constant Field Values
  - TELNET_DO
```
public static final byte TELNET_DO
```
    Command code: Do.
    
    See Also:
    
    Constant Field Values
  - TELNET_DONT
```
public static final byte TELNET_DONT
```
    Command code: Don't.
    
    See Also:
    
    Constant Field Values
  - TELNET_IAC
```
public static final byte TELNET_IAC
```
    Command code: Interpret As Command.
    
    See Also:
    
    Constant Field Values
  - TELNET_IS
```
public static final byte TELNET_IS
```
    Command code: IS.
    
    See Also:
    
    Constant Field Values
  - TELNET_SEND
```
public static final byte TELNET_SEND
```
    Command code: SEND.
    
    See Also:
    
    Constant Field Values
  - TELNET_OPTION_TRANSMIT_BINARY
```
public static final byte TELNET_OPTION_TRANSMIT_BINARY
```
    Option code: Transmit Binary option.
    
    See Also:
    
    Constant Field Values
  - TELNET_OPTION_ECHO
```
public static final byte TELNET_OPTION_ECHO
```
    Option code: Echo option.
    
    See Also:
    
    Constant Field Values
  - TELNET_OPTION_SUPPRESS_GA
```
public static final byte TELNET_OPTION_SUPPRESS_GA
```
    Option code: Suppress Go Ahead option.
    
    See Also:
    
    Constant Field Values
  - TELNET_OPTION_TERMINAL_TYPE
```
public static final byte TELNET_OPTION_TERMINAL_TYPE
```
    Option code: Terminal Type
    
    See Also:
    
    Constant Field Values
  - TELNET_OPTION_NAWS
```
public static final byte TELNET_OPTION_NAWS
```
    Option code: Negotitate About Window Size (NAWS)
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - TelnetProtocol
```
public TelnetProtocol(Socket socket,
                      TelnetCommandShell shell)
               throws IOException
```
    This constructor just initializes some internal object state from its arguments.
    
    Throws:
    
    IOException
- Method Detail
  - getOutputStream
```
public OutputStream getOutputStream()
```
  - setClientOutputStream
```
public void setClientOutputStream(OutputStream stream)
```
  - isConnected
```
public boolean isConnected()
```
    Returns true if the TCP connection represented by this object is connected, false otherwise.
  - isRemoteTelnetServer
```
public boolean isRemoteTelnetServer()
```
    Returns true if the TCP connection represented by this object is connected and the remote endpoint is a TELNET server, false otherwise.
  - setTerminalSize
```
public void setTerminalSize(int newWidth,
                            int newHeight)
```
    This method sets the terminal width and height to the supplied values. If either new value differs from the corresponding old value, we initiate a NAWS subnegotiation to inform the remote endpoint of the new terminal size.
  - localEcho
```
public boolean localEcho()
```
    Returns true if local echoing is enabled for this TCP connection, false otherwise.
  - run
```
public void run()
```
    This method runs in its own thread. It reads raw bytes from the TELNET connection socket, processes any TELNET protocol bytes (and removes them), and passes the remaining bytes to a TerminalDisplay object for display.
    
    Specified by:
    
    run in interface Runnable
    
    Overrides:
    
    run in class Thread
  - initializeOptions
```
protected void initializeOptions()
```
    This method initializes the localOptions[] and remoteOptions[] arrays so that they contain references to TelnetOption objects representing our desired state for each option. The goal is to achieve server-side echoing, suppression of Go Aheads, and to send the local terminal type and size to the remote endpoint.
  - processTelnetProtocol
```
protected int processTelnetProtocol(int count)
```
    Process TELNET protocol data contained in the first count bytes of rawBytes. This function preserves its state between calls, because a multi-byte TELNET command might be split between two (or more) calls to this function. The state is preserved in field telnetState. This function implements an FSA that recognizes TELNET option codes. TELNET option sub-negotiation is delegated to instances of TelnetOption.
    
    Returns:
    
    The number of bytes remaining in the buffer after removing all TELNET protocol bytes.
  - telnetServerDetected
```
protected void telnetServerDetected()
```
    This method is called whenever we receive a valid TELNET protocol command from the remote endpoint. When it is called for the first time for this connection, we negotiate all options that we desire to be enabled.
    This method does not negotiate options that we do not desire to be enabled, because all options are initially disabled.

Class TelnetProtocol

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

Field Summary

Fields inherited from class java.lang.Thread

Constructor Summary

Method Summary

Methods inherited from class java.lang.Thread

Methods inherited from class java.lang.Object

Field Detail

STATE_INITIAL

STATE_IAC_RECEIVED

STATE_WILL_RECEIVED

STATE_WONT_RECEIVED

STATE_DO_RECEIVED

STATE_DONT_RECEIVED

STATE_SUBNEGOTIATION_STARTED

STATE_RECEIVING_SUBNEGOTIATION

BUFFER_SIZE

rawBytes

processedBytes

processedStringBuffer

telnetState

remoteIsTelnetServer

localOptions

remoteOptions

receivedSubnegotiation

nextSubnegotiationByteIndex

ignoreSubnegotiation

width

height

shell

socket

inputChannel

serverOutputStream

clientOutputStream

localEcho

TELNET_SE

TELNET_NOP

TELNET_DM

TELNET_BREAK

TELNET_IP

TELNET_AO

TELNET_AYT

TELNET_EC

TELNET_EL

TELNET_GA

TELNET_SB

TELNET_WILL

TELNET_WONT

TELNET_DO

TELNET_DONT

TELNET_IAC

TELNET_IS

TELNET_SEND

TELNET_OPTION_TRANSMIT_BINARY

TELNET_OPTION_ECHO

TELNET_OPTION_SUPPRESS_GA

TELNET_OPTION_TERMINAL_TYPE

TELNET_OPTION_NAWS

Constructor Detail

TelnetProtocol

Method Detail

getOutputStream

setClientOutputStream

isConnected

isRemoteTelnetServer

setTerminalSize

localEcho

run

initializeOptions

processTelnetProtocol

telnetServerDetected