Package org.jline.terminal.impl.exec

Class ExecTerminalProvider

java.lang.Object

org.jline.terminal.impl.exec.ExecTerminalProvider

All Implemented Interfaces:

TerminalProvider

public class ExecTerminalProvider
extends Object
implements TerminalProvider

A terminal provider implementation that uses external commands to interact with the terminal.

The ExecTerminalProvider class provides a TerminalProvider implementation that uses external commands (such as stty, tput, etc.) to interact with the terminal. This approach allows JLine to work in environments where native libraries are not available or cannot be used, by relying on standard command-line utilities that are typically available on Unix-like systems.

This provider is typically used as a fallback when more direct methods of terminal interaction (such as JNI or JNA) are not available. While it provides good compatibility, it may have higher overhead due to the need to spawn external processes for many operations.

The provider name is "exec", which can be specified in the org.jline.terminal.provider system property to force the use of this provider.

See Also:

• TerminalProvider
• ExecPty

Constructor Summary

Constructors

Constructor	Description
ExecTerminalProvider()	Default constructor.

Method Summary

Modifier and Type	Method	Description
Pty	current(SystemStream systemStream)	Creates a Pty for the current terminal.
boolean	isPosixSystemStream(SystemStream stream)
boolean	isSystemStream(SystemStream stream)	Creates a new terminal with custom input and output streams.
boolean	isWindowsSystemStream(SystemStream stream)
String	name()	Returns the name of this terminal provider.
protected static ProcessBuilder.Redirect	newDescriptor(FileDescriptor fd)
Terminal	newTerminal(String name, String type, InputStream in, OutputStream out, Charset encoding, Charset inputEncoding, Charset outputEncoding, Terminal.SignalHandler signalHandler, boolean paused, Attributes attributes, Size size)	Creates a new terminal with custom input and output streams.
Terminal	posixSysTerminal(String name, String type, boolean ansiPassThrough, Charset encoding, boolean nativeSignals, Terminal.SignalHandler signalHandler, boolean paused, SystemStream systemStream)	Creates a terminal connected to a system stream on POSIX systems.
Terminal	posixSysTerminal(String name, String type, boolean ansiPassThrough, Charset encoding, Charset stdinEncoding, Charset stdoutEncoding, Charset stderrEncoding, boolean nativeSignals, Terminal.SignalHandler signalHandler, boolean paused, SystemStream systemStream)	Create a POSIX system terminal backed by the specified system stream.
String	systemStreamName(SystemStream stream)	Returns the name of the specified system stream on this platform.
int	systemStreamWidth(SystemStream stream)	Returns the width (number of columns) of the specified system stream.
Terminal	sysTerminal(String name, String type, boolean ansiPassThrough, Charset encoding, Charset inputEncoding, Charset outputEncoding, boolean nativeSignals, Terminal.SignalHandler signalHandler, boolean paused)	Creates a terminal connected to a system stream.
Terminal	sysTerminal(String name, String type, boolean ansiPassThrough, Charset encoding, Charset inputEncoding, Charset outputEncoding, boolean nativeSignals, Terminal.SignalHandler signalHandler, boolean paused, SystemStream systemStream)	Creates a terminal connected to a system stream.
String	toString()
Terminal	winSysTerminal(String name, String type, boolean ansiPassThrough, Charset encoding, boolean nativeSignals, Terminal.SignalHandler signalHandler, boolean paused, SystemStream systemStream)	Creates a terminal connected to a system stream.
Terminal	winSysTerminal(String name, String type, boolean ansiPassThrough, Charset encoding, Charset stdinEncoding, Charset stdoutEncoding, Charset stderrEncoding, boolean nativeSignals, Terminal.SignalHandler signalHandler, boolean paused, SystemStream systemStream)	Create a POSIX-style system terminal for Windows environments that provide a POSIX layer (Cygwin/MSYS); returns null on other Windows variants.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jline.terminal.spi.TerminalProvider

getConsoleCodepage, registerDefaultSignal, registerSignal, unregisterSignal

Constructor Details

ExecTerminalProvider

public ExecTerminalProvider()

Default constructor.

Method Details

name

public String name()

Returns the name of this terminal provider.

This method returns the name of this terminal provider, which is "exec". This name can be specified in the org.jline.terminal.provider system property to force the use of this provider.

Specified by:

name in interface TerminalProvider

Returns:

the name of this terminal provider ("exec")

current

public Pty current(SystemStream systemStream)
            throws IOException

Creates a Pty for the current terminal.

This method creates an ExecPty instance for the current terminal by executing the 'tty' command to determine the terminal device name. It is used to obtain a Pty object that can interact with the current terminal using external commands.

Parameters:

systemStream - the system stream to associate with the Pty

Returns:

a new ExecPty instance for the current terminal

Throws:

IOException - if the current terminal is not a TTY or if an error occurs while executing the 'tty' command

sysTerminal

public Terminal sysTerminal(String name,
 String type,
 boolean ansiPassThrough,
 Charset encoding,
 Charset inputEncoding,
 Charset outputEncoding,
 boolean nativeSignals,
 Terminal.SignalHandler signalHandler,
 boolean paused)
                     throws IOException

Creates a terminal connected to a system stream.

This method creates a terminal that is connected to one of the standard system streams (standard input, standard output, or standard error). It uses the ExecPty implementation to interact with the terminal using external commands.

Specified by:

sysTerminal in interface TerminalProvider

Parameters:

name - the name of the terminal

type - the terminal type (e.g., "xterm", "dumb")

ansiPassThrough - whether to pass through ANSI escape sequences

encoding - the character encoding to use

inputEncoding - the character encoding to use for input

outputEncoding - the character encoding to use for output

nativeSignals - whether to use native signal handling

signalHandler - the signal handler to use

paused - whether the terminal should start in a paused state

systemStream - the system stream to connect to

Returns:

a new terminal connected to the specified system stream

Throws:

IOException - if an I/O error occurs

sysTerminal

public Terminal sysTerminal(String name,
 String type,
 boolean ansiPassThrough,
 Charset encoding,
 Charset inputEncoding,
 Charset outputEncoding,
 boolean nativeSignals,
 Terminal.SignalHandler signalHandler,
 boolean paused,
 SystemStream systemStream)
                     throws IOException

Description copied from interface: TerminalProvider

Creates a terminal connected to a system stream.

This method creates a terminal that is connected to one of the standard system streams (standard input, standard output, or standard error). Such terminals typically represent the actual terminal window or console that the application is running in.

Specified by:

sysTerminal in interface TerminalProvider

Parameters:

name - the name of the terminal

type - the terminal type (e.g., "xterm", "dumb")

ansiPassThrough - whether to pass through ANSI escape sequences (only used on Windows)

encoding - the general character encoding to use

inputEncoding - the character encoding to use for input

outputEncoding - the character encoding to use for output

nativeSignals - whether to use native signal handling

signalHandler - the signal handler to use

paused - whether the terminal should start in a paused state (only used on Windows)

systemStream - the system stream to connect to

Returns:

a new terminal connected to the specified system stream

Throws:

IOException - if an I/O error occurs

winSysTerminal

public Terminal winSysTerminal(String name,
 String type,
 boolean ansiPassThrough,
 Charset encoding,
 boolean nativeSignals,
 Terminal.SignalHandler signalHandler,
 boolean paused,
 SystemStream systemStream)
                        throws IOException

Creates a terminal connected to a system stream.

This method creates a terminal that is connected to one of the standard system streams (standard input, standard output, or standard error). It uses the ExecPty implementation to interact with the terminal using external commands.

Parameters:

name - the name of the terminal

type - the terminal type (e.g., "xterm", "dumb")

ansiPassThrough - whether to pass through ANSI escape sequences

encoding - the character encoding to use

nativeSignals - whether to use native signal handling

signalHandler - the signal handler to use

paused - whether the terminal should start in a paused state

systemStream - the system stream to connect to

name - the name of the terminal

type - the terminal type (e.g., "xterm", "dumb")

ansiPassThrough - whether to pass through ANSI escape sequences

encoding - the character encoding to use

nativeSignals - whether to use native signal handling

signalHandler - the signal handler to use

paused - whether the terminal should start in a paused state

systemStream - the system stream to connect to

Returns:

a new terminal connected to the specified system stream

Throws:

IOException - if an I/O error occurs /** Creates a terminal connected to a system stream on Windows.

This method creates a terminal that is connected to one of the standard system streams on Windows. It uses the ExecPty implementation to interact with the terminal using external commands.

Note that on Windows, the exec provider has limited functionality and may not work as well as the native providers (JNI, JNA, etc.).

IOException - if an I/O error occurs

winSysTerminal

public Terminal winSysTerminal(String name,
 String type,
 boolean ansiPassThrough,
 Charset encoding,
 Charset stdinEncoding,
 Charset stdoutEncoding,
 Charset stderrEncoding,
 boolean nativeSignals,
 Terminal.SignalHandler signalHandler,
 boolean paused,
 SystemStream systemStream)
                        throws IOException

Create a POSIX-style system terminal for Windows environments that provide a POSIX layer (Cygwin/MSYS); returns null on other Windows variants.

Parameters:

name - the terminal name

type - the terminal type (TERM)

ansiPassThrough - whether ANSI sequences should be passed through (unused for POSIX path)

encoding - the general charset for the terminal

stdinEncoding - charset to use for stdin

stdoutEncoding - charset to use for stdout

stderrEncoding - charset to use for stderr

nativeSignals - whether native signal handling is enabled

signalHandler - handler for terminal signals

paused - whether the terminal should be created in a paused state

systemStream - the system stream to associate with the terminal; determines which output encoding (stdout vs stderr) is selected

Returns:

a configured PosixSysTerminal when running under Cygwin or MSYS, null otherwise

Throws:

IOException

posixSysTerminal

public Terminal posixSysTerminal(String name,
 String type,
 boolean ansiPassThrough,
 Charset encoding,
 boolean nativeSignals,
 Terminal.SignalHandler signalHandler,
 boolean paused,
 SystemStream systemStream)
                          throws IOException

Creates a terminal connected to a system stream on POSIX systems.

This method creates a terminal that is connected to one of the standard system streams on POSIX systems (Linux, macOS, etc.). It uses the ExecPty implementation to interact with the terminal using external commands.

Parameters:

name - the name of the terminal

type - the terminal type (e.g., "xterm", "dumb")

ansiPassThrough - whether to pass through ANSI escape sequences

encoding - the character encoding to use

nativeSignals - whether to use native signal handling

signalHandler - the signal handler to use

paused - whether the terminal should start in a paused state

systemStream - the system stream to connect to

Returns:

a new terminal connected to the specified system stream

Throws:

IOException - if an I/O error occurs

posixSysTerminal

public Terminal posixSysTerminal(String name,
 String type,
 boolean ansiPassThrough,
 Charset encoding,
 Charset stdinEncoding,
 Charset stdoutEncoding,
 Charset stderrEncoding,
 boolean nativeSignals,
 Terminal.SignalHandler signalHandler,
 boolean paused,
 SystemStream systemStream)
                          throws IOException

Create a POSIX system terminal backed by the specified system stream.

Parameters:

name - the terminal name

type - the terminal type

ansiPassThrough - whether ANSI sequences should be passed through (platform-dependent)

encoding - the terminal's primary character encoding

stdinEncoding - the encoding to use for standard input

stdoutEncoding - the encoding to use for standard output (used when systemStream is not Error)

stderrEncoding - the encoding to use for standard error (used when systemStream is Error)

nativeSignals - whether native signal handling is enabled

signalHandler - handler for terminal signals

paused - whether the terminal should be created in a paused state

systemStream - the system stream to back the terminal; selects the output encoding (uses stderrEncoding when SystemStream.Error, otherwise stdoutEncoding)

Returns:

a POSIX-based Terminal instance connected to the chosen system stream

Throws:

IOException - if obtaining the underlying PTY or creating the terminal fails

newTerminal

public Terminal newTerminal(String name,
 String type,
 InputStream in,
 OutputStream out,
 Charset encoding,
 Charset inputEncoding,
 Charset outputEncoding,
 Terminal.SignalHandler signalHandler,
 boolean paused,
 Attributes attributes,
 Size size)
                     throws IOException

Creates a new terminal with custom input and output streams.

This method creates a terminal that is connected to the specified input and output streams. It creates an ExternalTerminal that emulates the line discipline functionality typically provided by the operating system's terminal driver.

Specified by:

newTerminal in interface TerminalProvider

Parameters:

name - the name of the terminal

type - the terminal type (e.g., "xterm", "dumb")

in - the input stream to read from

out - the output stream to write to

encoding - the character encoding to use

inputEncoding - the character encoding to use for input

outputEncoding - the character encoding to use for output

signalHandler - the signal handler to use

paused - whether the terminal should start in a paused state

attributes - the initial terminal attributes

size - the initial terminal size

Returns:

a new terminal connected to the specified streams

Throws:

IOException - if an I/O error occurs

isSystemStream

public boolean isSystemStream(SystemStream stream)

Creates a new terminal with custom input and output streams.

This method creates a terminal that is connected to the specified input and output streams. It creates an ExternalTerminal that emulates the line discipline functionality typically provided by the operating system's terminal driver.

Specified by:

isSystemStream in interface TerminalProvider

Parameters:

stream - the system stream to check

name - the name of the terminal

type - the terminal type (e.g., "xterm", "dumb")

in - the input stream to read from

out - the output stream to write to

encoding - the character encoding to use

signalHandler - the signal handler to use

paused - whether the terminal should start in a paused state

attributes - the initial terminal attributes

size - the initial terminal size

Returns:

a new terminal connected to the specified streams

Throws:

IOException - if an I/O error occurs /** Checks if the specified system stream is available on this platform.

This method determines whether the specified system stream (standard input, standard output, or standard error) is available for use on the current platform. It checks both POSIX and Windows system streams.

isWindowsSystemStream

public boolean isWindowsSystemStream(SystemStream stream)

isPosixSystemStream

public boolean isPosixSystemStream(SystemStream stream)

systemStreamName

public String systemStreamName(SystemStream stream)

Returns the name of the specified system stream on this platform.

This method returns a platform-specific name or identifier for the specified system stream. The name may be used for display purposes or for accessing the stream through platform-specific APIs.

Specified by:

systemStreamName in interface TerminalProvider

Parameters:

stream - the system stream

Returns:

the name of the system stream on this platform

systemStreamWidth

public int systemStreamWidth(SystemStream stream)

Returns the width (number of columns) of the specified system stream.

This method determines the width of the terminal associated with the specified system stream. The width is measured in character cells and represents the number of columns available for display.

This implementation uses the 'tput cols' command to determine the terminal width. If the command fails or returns an invalid value, a default width of 80 columns is returned.

Specified by:

systemStreamWidth in interface TerminalProvider

Parameters:

stream - the system stream

Returns:

the width of the system stream in character columns

newDescriptor

protected static ProcessBuilder.Redirect newDescriptor(FileDescriptor fd)

toString

public String toString()

Overrides:

toString in class Object