Class UnixLikeTerminal

java.lang.Object

com.googlecode.lanterna.terminal.AbstractTerminal

com.googlecode.lanterna.terminal.ansi.StreamBasedTerminal

com.googlecode.lanterna.terminal.ansi.ANSITerminal

com.googlecode.lanterna.terminal.ansi.UnixLikeTerminal

All Implemented Interfaces:

Scrollable, InputProvider, ExtendedTerminal, Terminal, Closeable, AutoCloseable

Direct Known Subclasses:

UnixLikeTTYTerminal

public abstract class UnixLikeTerminal
extends ANSITerminal

Base class for all terminals that generally behave like Unix terminals. This class defined a number of abstract methods that needs to be implemented which are all used to setup the terminal environment (turning off echo, canonical mode, etc) and also a control variable for how to react to CTRL+c keystroke.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	UnixLikeTerminal.CtrlCBehaviour	This enum lets you control how Lanterna will handle a ctrl+c keystroke from the user.

Field Summary

Fields

Modifier and Type	Field	Description
private boolean	acquired
private final boolean	catchSpecialCharacters
private final Thread	shutdownHook
private final UnixLikeTerminal.CtrlCBehaviour	terminalCtrlCBehaviour

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	UnixLikeTerminal(InputStream terminalInput, OutputStream terminalOutput, Charset terminalCharset, UnixLikeTerminal.CtrlCBehaviour terminalCtrlCBehaviour)

Method Summary

Modifier and Type	Method	Description
protected void	acquire()	Effectively taking over the terminal and enabling it for Lanterna to use, by turning off echo and canonical mode, adding resize listeners and optionally trap unix signals.
protected abstract void	canonicalMode(boolean enabled)	In canonical mode, data are accumulated in a line editing buffer, and do not become "available for reading" until line editing has been terminated by the user sending a line delimiter character.
void	close()	Closes the terminal, if applicable.
private void	exitPrivateModeAndRestoreState()
protected UnixLikeTerminal.CtrlCBehaviour	getTerminalCtrlCBehaviour()
private void	isCtrlC(KeyStroke key)
protected abstract void	keyEchoEnabled(boolean enabled)	Enables or disable key echo mode, which means when the user press a key, the terminal will immediately print that key to the terminal.
protected abstract void	keyStrokeSignalsEnabled(boolean enabled)	This method causes certain keystrokes (at the moment only ctrl+c) to be passed in to the program as a regular KeyStroke instead of as a signal to the JVM process.
KeyStroke	pollInput()	Returns the next Key off the input queue or null if there is no more input events available.
KeyStroke	readInput()	Returns the next Key off the input queue or blocks until one is available.
protected abstract void	registerTerminalResizeListener(Runnable onResize)
protected abstract void	restoreTerminalSettings()	Restores the terminal settings from last time saveTerminalSettings() was called
private void	restoreTerminalSettingsAndKeyStrokeSignals()
protected abstract void	saveTerminalSettings()	Stores the current terminal device settings (the ones that are modified through this interface) so that they can be restored later using restoreTerminalSettings()

Methods inherited from class ANSITerminal

clearScreen, deiconify, disableSGR, enableSGR, enterPrivateMode, exitPrivateMode, findTerminalSize, getCursorPosition, getDefaultKeyDecodingProfile, getTerminalSize, iconify, isInPrivateMode, maximize, popTitle, pushTitle, reportPosition, resetColorAndSGR, restoreCursorPosition, saveCursorPosition, scrollLines, setBackgroundColor, setCursorPosition, setCursorPosition, setCursorVisible, setForegroundColor, setMouseCaptureMode, setTerminalSize, setTitle, unmaximize

Methods inherited from class StreamBasedTerminal

bell, enquireTerminal, flush, getCharset, getInputDecoder, putCharacter, putString, resetMemorizedCursorPosition, translateCharacter, waitForCursorPositionReport, writeToTerminal

Methods inherited from class AbstractTerminal

addResizeListener, newTextGraphics, onResized, onResized, removeResizeListener

Methods inherited from class Object

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

Methods inherited from interface Terminal

addResizeListener, bell, enquireTerminal, flush, newTextGraphics, putCharacter, putString, removeResizeListener

Field Details

terminalCtrlCBehaviour

private final UnixLikeTerminal.CtrlCBehaviour terminalCtrlCBehaviour

catchSpecialCharacters

private final boolean catchSpecialCharacters

shutdownHook

private final Thread shutdownHook

acquired

private boolean acquired

Constructor Details

UnixLikeTerminal

protected UnixLikeTerminal(InputStream terminalInput,
 OutputStream terminalOutput,
 Charset terminalCharset,
 UnixLikeTerminal.CtrlCBehaviour terminalCtrlCBehaviour)
                    throws IOException

Throws:

IOException

Method Details

acquire

protected void acquire()
                throws IOException

Effectively taking over the terminal and enabling it for Lanterna to use, by turning off echo and canonical mode, adding resize listeners and optionally trap unix signals. This should be called automatically by the constructor of any end-user class extending from UnixLikeTerminal

Throws:

IOException - If there was an I/O error

close

public void close()
           throws IOException

Description copied from interface: Terminal

Closes the terminal, if applicable. If the implementation doesn't support closing the terminal, this will do nothing. The Swing/AWT emulator implementations will translate this into a dispose() call on the UI resources, the telnet implementation will hang out the connection.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in interface Terminal

Overrides:

close in class ANSITerminal

Throws:

IOException - If there was an underlying I/O error

pollInput

public KeyStroke pollInput()
                    throws IOException

Description copied from interface: InputProvider

Returns the next Key off the input queue or null if there is no more input events available. Note, this method call is not blocking, it returns null immediately if there is nothing on the input stream.

Specified by:

pollInput in interface InputProvider

Overrides:

pollInput in class ANSITerminal

Returns:

Key object which represents a keystroke coming in through the input stream

Throws:

IOException - Propagated error if the underlying stream gave errors

readInput

public KeyStroke readInput()
                    throws IOException

Description copied from interface: InputProvider

Returns the next Key off the input queue or blocks until one is available. NOTE: In previous versions of Lanterna, this method was not blocking. From lanterna 3, it is blocking and you can call pollInput() for the non-blocking version.

Specified by:

readInput in interface InputProvider

Overrides:

readInput in class ANSITerminal

Returns:

Key object which represents a keystroke coming in through the input stream

Throws:

IOException - Propagated error if the underlying stream gave errors

getTerminalCtrlCBehaviour

protected UnixLikeTerminal.CtrlCBehaviour getTerminalCtrlCBehaviour()

registerTerminalResizeListener

protected abstract void registerTerminalResizeListener(Runnable onResize)
                                                throws IOException

Throws:

IOException

saveTerminalSettings

protected abstract void saveTerminalSettings()
                                      throws IOException

Stores the current terminal device settings (the ones that are modified through this interface) so that they can be restored later using restoreTerminalSettings()

Throws:

IOException - If there was an I/O error when altering the terminal environment

restoreTerminalSettings

protected abstract void restoreTerminalSettings()
                                         throws IOException

Restores the terminal settings from last time saveTerminalSettings() was called

Throws:

IOException - If there was an I/O error when altering the terminal environment

restoreTerminalSettingsAndKeyStrokeSignals

private void restoreTerminalSettingsAndKeyStrokeSignals()
                                                 throws IOException

Throws:

IOException

keyEchoEnabled

protected abstract void keyEchoEnabled(boolean enabled)
                                throws IOException

Enables or disable key echo mode, which means when the user press a key, the terminal will immediately print that key to the terminal. Normally for Lanterna, this should be turned off so the software can take the key as an input event, put it on the input queue and then depending on the code decide what to do with it.

Parameters:

enabled - true if key echo should be enabled, false otherwise

Throws:

IOException - If there was an I/O error when altering the terminal environment

canonicalMode

protected abstract void canonicalMode(boolean enabled)
                               throws IOException

In canonical mode, data are accumulated in a line editing buffer, and do not become "available for reading" until line editing has been terminated by the user sending a line delimiter character. This is usually the default mode for a terminal. Lanterna wants to read each character as they are typed, without waiting for the final newline, so it will attempt to turn canonical mode off on initialization.

Parameters:

enabled - true if canonical input mode should be enabled, false otherwise

Throws:

IOException - If there was an I/O error when altering the terminal environment

keyStrokeSignalsEnabled

protected abstract void keyStrokeSignalsEnabled(boolean enabled)
                                         throws IOException

This method causes certain keystrokes (at the moment only ctrl+c) to be passed in to the program as a regular KeyStroke instead of as a signal to the JVM process. For example, ctrl+c will normally send an interrupt that causes the JVM to shut down, but this method will make it pass in ctrl+c as a regular KeyStroke instead. You can of course still make ctrl+c kill the application through your own input handling if you like.

Please note that this method is called automatically by lanterna to disable signals unless you define a system property "com.googlecode.lanterna.terminal.UnixTerminal.catchSpecialCharacters" and set it to the string "false".

Parameters:

enabled - Pass in true if you want keystrokes to generate system signals (like process interrupt), false if you want lanterna to catch and interpret these keystrokes are regular keystrokes

Throws:

IOException - If there was an I/O error when attempting to disable special characters

See Also:

• UnixLikeTerminal.CtrlCBehaviour

isCtrlC

private void isCtrlC(KeyStroke key)
              throws IOException

Throws:

IOException

exitPrivateModeAndRestoreState

private void exitPrivateModeAndRestoreState()