Package org.jline.terminal.impl

Class AbstractUnixSysTerminal

java.lang.Object

org.jline.terminal.impl.AbstractTerminal

org.jline.terminal.impl.AbstractUnixSysTerminal

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable, Sized, TerminalExt, Terminal

Direct Known Subclasses:

FfmUnixSysTerminal, JniUnixSysTerminal

public abstract class AbstractUnixSysTerminal
extends AbstractTerminal

Base class for flattened POSIX system terminals that bypass the PTY abstraction.

Subclasses only need to implement four methods for platform-specific attribute and size operations:

• doGetAttributes()
• doSetAttributes(Attributes)
• doGetSize()
• doSetSize(Sized)

The call chain is reduced from 7 layers to 4:

   Terminal → AbstractTerminal → AbstractUnixSysTerminal → subclass → native call
 

Important: the underlying system streams (FileDescriptor.in, FileDescriptor.out/err) are wrapped in NonCloseableInputStream / NonCloseableOutputStream. Closing the terminal will shut down the pump thread and release resources, but will not close the shared file descriptors. This prevents breaking System.in/System.out for the rest of the JVM.

Nested Class Summary

Nested classes/interfaces inherited from interface org.jline.terminal.Terminal

Terminal.MouseTracking, Terminal.Signal, Terminal.SignalHandler

Field Summary

Fields

Modifier and Type	Field	Description
protected static final int	STDERR_FD
protected static final int	STDIN_FD
protected static final int	STDOUT_FD

Fields inherited from class org.jline.terminal.impl.AbstractTerminal

bools, closed, currentMouseTracking, encoding, handlers, inputEncoding, ints, name, onClose, outputEncoding, palette, status, strings, type

Fields inherited from interface org.jline.terminal.Terminal

TYPE_DUMB, TYPE_DUMB_COLOR

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractUnixSysTerminal(TerminalProvider provider, SystemStream systemStream, String name, String type, Charset encoding, Charset inputEncoding, Charset outputEncoding, boolean nativeSignals, Terminal.SignalHandler signalHandler, Attributes originalAttributes)

Method Summary

Modifier and Type	Method	Description
protected void	doClose()
protected abstract Attributes	doGetAttributes()
protected abstract Size	doGetSize()
protected abstract void	doSetAttributes(Attributes attr)
protected abstract void	doSetSize(Sized size)
Attributes	getAttributes()	Returns the current terminal attributes.
Cursor	getCursorPosition(IntConsumer discarded)	Query the terminal to report the cursor position.
int	getDefaultBackgroundColor()	Get the terminal's default background color.
int	getDefaultForegroundColor()	Get the terminal's default foreground color.
TerminalProvider	getProvider()	Returns the terminal provider that created this terminal.
Size	getSize()	Retrieve the size of the visible window
SystemStream	getSystemStream()	Returns the system stream associated with this terminal, if any.
Terminal.SignalHandler	handle(Terminal.Signal signal, Terminal.SignalHandler handler)	Registers a handler for the given Terminal.Signal.
InputStream	input()	Retrieve the input stream for this terminal.
OutputStream	output()	Retrieve the output stream for this terminal.
NonBlockingReader	reader()	Retrieve the Reader for this terminal.
void	setAttributes(Attributes attr)	Sets the terminal attributes to the specified values.
void	setSize(Sized size)	Requests that the terminal adopt the specified window dimensions.
String	toString()
PrintWriter	writer()	Retrieve the Writer for this terminal.

Methods inherited from class org.jline.terminal.impl.AbstractTerminal

canPauseResume, checkClosed, checkInterrupted, close, detectTrueColorSupport, echo, echo, echoSignal, encoding, enterRawMode, flush, getBooleanCapability, getCurrentMouseTracking, getGraphemeClusterMode, getKind, getName, getNumericCapability, getPalette, getStatus, getStatus, getStringCapability, getType, hasFocusSupport, hasMouseSupport, inputEncoding, isClusterGrouped, outputEncoding, parseInfoCmp, pause, pause, paused, puts, raise, readMouseEvent, readMouseEvent, readMouseEvent, readMouseEvent, resume, setGraphemeClusterMode, setOnClose, supportsGraphemeClusterMode, trackFocus, trackMouse

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jline.terminal.Terminal

getBufferSize, getColumns, getHeight, getRows, getWidth, setSize

Field Details

STDIN_FD

protected static final int STDIN_FD

See Also:

• Constant Field Values

STDOUT_FD

protected static final int STDOUT_FD

See Also:

• Constant Field Values

STDERR_FD

protected static final int STDERR_FD

See Also:

• Constant Field Values

Constructor Details

AbstractUnixSysTerminal

protected AbstractUnixSysTerminal(TerminalProvider provider,
 SystemStream systemStream,
 String name,
 String type,
 Charset encoding,
 Charset inputEncoding,
 Charset outputEncoding,
 boolean nativeSignals,
 Terminal.SignalHandler signalHandler,
 Attributes originalAttributes)
                           throws IOException

Throws:

IOException

Method Details

handle

public Terminal.SignalHandler handle(Terminal.Signal signal,
 Terminal.SignalHandler handler)

Description copied from interface: Terminal

Registers a handler for the given Terminal.Signal.

This method allows the application to specify custom behavior when a particular signal is raised. The handler's Terminal.SignalHandler.handle(Signal) method will be called whenever the specified signal is raised.

Note that the JVM does not easily allow catching the Terminal.Signal.QUIT signal (Ctrl+\), which typically causes a thread dump to be displayed. This signal handling is mainly effective when connecting through an SSH socket to a virtual terminal.

Example usage:

 Terminal terminal = TerminalBuilder.terminal();

 // Handle window resize events
 terminal.handle(Signal.WINCH, signal -> {
     Size size = terminal.getSize();
     terminal.writer().println("\nTerminal resized to " +
                              size.getColumns() + "x" + size.getRows());
     terminal.flush();
 });

 // Ignore interrupt signal
 terminal.handle(Signal.INT, SignalHandler.SIG_IGN);
 

Specified by:

handle in interface Terminal

Overrides:

handle in class AbstractTerminal

Parameters:

signal - the signal to register a handler for

handler - the handler to be called when the signal is raised

Returns:

the previous signal handler that was registered for this signal

See Also:

• Terminal.Signal
• Terminal.SignalHandler
• Terminal.raise(Signal)

doGetAttributes

protected abstract Attributes doGetAttributes()

doSetAttributes

protected abstract void doSetAttributes(Attributes attr)

doGetSize

protected abstract Size doGetSize()

doSetSize

protected abstract void doSetSize(Sized size)

getAttributes

public Attributes getAttributes()

Description copied from interface: Terminal

Returns the current terminal attributes.

Terminal attributes control various aspects of terminal behavior, including:

• Input processing - How input characters are processed (e.g., character mapping, parity checking)
• Output processing - How output characters are processed (e.g., newline translation)
• Control settings - Hardware settings like baud rate and character size
• Local settings - Terminal behavior settings like echo, canonical mode, and signal generation
• Control characters - Special characters like EOF, interrupt, and erase

The returned Attributes object is a copy of the terminal's current attributes and can be safely modified without affecting the terminal until it is applied using Terminal.setAttributes(Attributes). This allows for making multiple changes to the attributes before applying them all at once.

Example usage:

 Terminal terminal = TerminalBuilder.terminal();

 // Get current attributes
 Attributes attrs = terminal.getAttributes();

 // Modify attributes
 attrs.setLocalFlag(LocalFlag.ECHO, false);      // Disable echo
 attrs.setInputFlag(InputFlag.ICRNL, false);     // Disable CR to NL mapping
 attrs.setControlChar(ControlChar.VMIN, 1);      // Set minimum input to 1 character
 attrs.setControlChar(ControlChar.VTIME, 0);     // Set timeout to 0 deciseconds

 // Apply modified attributes
 terminal.setAttributes(attrs);
 

Returns:

a copy of the terminal's current attributes

See Also:

• Terminal.setAttributes(Attributes)
• Attributes
• Terminal.enterRawMode()

setAttributes

public void setAttributes(Attributes attr)

Description copied from interface: Terminal

Sets the terminal attributes to the specified values.

This method applies the specified attributes to the terminal, changing its behavior according to the settings in the Attributes object. The terminal makes a copy of the provided attributes, so further modifications to the attr object will not affect the terminal until this method is called again.

Terminal attributes control various aspects of terminal behavior, including input and output processing, control settings, local settings, and special control characters. Changing these attributes allows for fine-grained control over how the terminal processes input and output.

Common attribute modifications include:

• Disabling echo for password input
• Enabling/disabling canonical mode for line-by-line or character-by-character input
• Disabling signal generation for custom handling of Ctrl+C and other control sequences
• Changing control characters like the interrupt character or end-of-file character

For convenience, the Terminal.enterRawMode() method provides a pre-configured set of attributes suitable for full-screen interactive applications.

Example usage:

 Terminal terminal = TerminalBuilder.terminal();

 // Save original attributes for later restoration
 Attributes originalAttrs = terminal.getAttributes();

 try {
     // Create and configure new attributes
     Attributes attrs = new Attributes(originalAttrs);
     attrs.setLocalFlag(LocalFlag.ECHO, false);      // Disable echo for password input
     attrs.setLocalFlag(LocalFlag.ICANON, false);    // Disable canonical mode

     // Apply the new attributes
     terminal.setAttributes(attrs);

     // Use terminal with modified attributes...
 } finally {
     // Restore original attributes
     terminal.setAttributes(originalAttrs);
 }
 

Parameters:

attr - the attributes to apply to the terminal

See Also:

• Terminal.getAttributes()
• Attributes
• Terminal.enterRawMode()

getSize

public Size getSize()

Description copied from interface: Terminal

Retrieve the size of the visible window

Returns:

the visible terminal size

See Also:

• Terminal.getBufferSize()

setSize

public void setSize(Sized size)

Description copied from interface: Terminal

Requests that the terminal adopt the specified window dimensions. Implementations may apply constraints or ignore the request if resizing is unsupported; callers should use Terminal.getSize() to observe the effective size after calling this method.

Parameters:

size - the desired terminal size (columns and rows)

See Also:

• Terminal.getSize()

reader

public NonBlockingReader reader()

Description copied from interface: Terminal

Retrieve the Reader for this terminal. This is the standard way to read input from this terminal. The reader is non blocking.

The returned reader is owned by this terminal and will be closed when the terminal is closed. Callers should not close it directly.

Returns:

The non blocking reader

writer

public PrintWriter writer()

Description copied from interface: Terminal

Retrieve the Writer for this terminal. This is the standard way to write to this terminal.

The returned writer is owned by this terminal and will be closed when the terminal is closed. Callers should not close it directly.

Returns:

The writer

input

public InputStream input()

Description copied from interface: Terminal

Retrieve the input stream for this terminal. In some rare cases, there may be a need to access the terminal input stream directly. In the usual cases, use the Terminal.reader() instead.

The returned stream is owned by this terminal and will be closed when the terminal is closed. Callers should not close it directly.

Returns:

The input stream

See Also:

• Terminal.reader()

output

public OutputStream output()

Description copied from interface: Terminal

Retrieve the output stream for this terminal. In some rare cases, there may be a need to access the terminal output stream directly. In the usual cases, use the Terminal.writer() instead.

The returned stream is owned by this terminal and will be closed when the terminal is closed. Callers should not close it directly.

Returns:

The output stream

See Also:

• Terminal.writer()

getProvider

public TerminalProvider getProvider()

Description copied from interface: TerminalExt

Returns the terminal provider that created this terminal.

The terminal provider is responsible for creating and managing terminal instances on a specific platform. This method allows access to the provider that created this terminal, which can be useful for accessing provider-specific functionality or for creating additional terminals with the same provider.

Returns:

the TerminalProvider that created this terminal, or null if the terminal was created with no provider

See Also:

• TerminalProvider

getSystemStream

public SystemStream getSystemStream()

Description copied from interface: TerminalExt

Returns the system stream associated with this terminal, if any.

This method indicates whether the terminal is bound to a standard system stream (standard input, standard output, or standard error). Terminals that are connected to system streams typically represent the actual terminal window or console that the application is running in.

Returns:

the underlying system stream, which may be SystemStream.Input, SystemStream.Output, SystemStream.Error, or null if this terminal is not bound to a system stream

See Also:

• SystemStream

getCursorPosition

public Cursor getCursorPosition(IntConsumer discarded)

Description copied from interface: Terminal

Query the terminal to report the cursor position. As the response is read from the input stream, some characters may be read before the cursor position is actually read. Those characters can be given back using org.jline.keymap.BindingReader#runMacro(String)

Specified by:

getCursorPosition in interface Terminal

Overrides:

getCursorPosition in class AbstractTerminal

Parameters:

discarded - a consumer receiving discarded characters

Returns:

null if cursor position reporting is not supported or a valid cursor position

doClose

protected void doClose()
                throws IOException

Overrides:

doClose in class AbstractTerminal

Throws:

IOException

getDefaultForegroundColor

public int getDefaultForegroundColor()

Description copied from class: AbstractTerminal

Get the terminal's default foreground color. This method should be overridden by concrete implementations.

Specified by:

getDefaultForegroundColor in interface Terminal

Overrides:

getDefaultForegroundColor in class AbstractTerminal

Returns:

the RGB value of the default foreground color, or -1 if not available

See Also:

• Terminal.getDefaultBackgroundColor()
• Terminal.getPalette()

getDefaultBackgroundColor

public int getDefaultBackgroundColor()

Description copied from class: AbstractTerminal

Get the terminal's default background color. This method should be overridden by concrete implementations.

Specified by:

getDefaultBackgroundColor in interface Terminal

Overrides:

getDefaultBackgroundColor in class AbstractTerminal

Returns:

the RGB value of the default background color, or -1 if not available

See Also:

• Terminal.getDefaultForegroundColor()
• Terminal.getPalette()

toString

public String toString()

Overrides:

toString in class AbstractTerminal