Package org.jline.terminal.impl.exec

Class ExecPty

java.lang.Object

org.jline.terminal.impl.AbstractPty

org.jline.terminal.impl.exec.ExecPty

All Implemented Interfaces:

Closeable, AutoCloseable, Pty

public class ExecPty
extends AbstractPty
implements Pty

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

The ExecPty class provides a Pty 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 implementation executes external commands to perform operations such as:

• Getting and setting terminal attributes
• Getting and setting terminal size
• Determining the current terminal device

The ExecPty 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.

See Also:

• AbstractPty
• Pty

Field Summary

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

provider, systemStream

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ExecPty(TerminalProvider provider, SystemStream systemStream, String name)	Creates a new ExecPty instance.

Method Summary

Modifier and Type	Method	Description
void	close()	Closes this Pty.
static Pty	current(TerminalProvider provider, SystemStream systemStream)	Creates an ExecPty instance for the current terminal.
static Attributes	doGetAttr(String cfg)
protected String	doGetConfig()
protected InputStream	doGetSlaveInput()
protected void	doSetAttr(Attributes attr)
Attributes	getAttr()	Returns the current terminal attributes for this PTY.
protected List<String>	getFlagsToSet(Attributes attr, Attributes current)
InputStream	getMasterInput()	Returns the input stream for the master side of the PTY.
OutputStream	getMasterOutput()	Returns the output stream for the master side of the PTY.
String	getName()	Returns the name of the terminal device.
Size	getSize()	Returns the current size (dimensions) of this PTY.
OutputStream	getSlaveOutput()	Returns the output stream for the slave side of the PTY.
void	setSize(Size size)	Sets the size (dimensions) of this PTY.
String	toString()

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

checkInterrupted, getProvider, getSlaveInput, getSystemStream, newDescriptor, setAttr

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.Pty

getProvider, getSlaveInput, getSystemStream, setAttr

Constructor Details

ExecPty

protected ExecPty(TerminalProvider provider,
 SystemStream systemStream,
 String name)

Creates a new ExecPty instance.

This constructor creates a new ExecPty instance with the specified provider, system stream, and terminal device name. It is protected because instances should typically be created using the current(TerminalProvider, SystemStream) method.

Parameters:

provider - the terminal provider that will own this Pty

systemStream - the system stream associated with this Pty

name - the name of the terminal device (e.g., "/dev/tty")

Method Details

current

public static Pty current(TerminalProvider provider,
 SystemStream systemStream)
                   throws IOException

Creates an ExecPty instance 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:

provider - the terminal provider that will own this Pty

systemStream - the system stream (must be Output or Error) associated with this 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

IllegalArgumentException - if systemStream is not Output or Error

close

public void close()
           throws IOException

Closes this Pty.

This implementation does nothing, as there are no resources to release. The terminal device is not actually opened by this class, so it does not need to be closed.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException - if an I/O error occurs (never thrown by this implementation)

getName

public String getName()

Returns the name of the terminal device.

This method returns the name of the terminal device associated with this Pty, which was determined when the Pty was created. This is typically a device path such as "/dev/tty" or "/dev/pts/0".

Returns:

the name of the terminal device

getMasterInput

public InputStream getMasterInput()

Description copied from interface: Pty

Returns the input stream for the master side of the PTY.

This stream receives data that has been written to the slave's output stream. Terminal emulators typically read from this stream to get the output from processes running in the terminal.

Specified by:

getMasterInput in interface Pty

Returns:

the master's input stream

getMasterOutput

public OutputStream getMasterOutput()

Description copied from interface: Pty

Returns the output stream for the master side of the PTY.

Data written to this stream will be available for reading from the slave's input stream. Terminal emulators typically write to this stream to send input to processes running in the terminal.

Specified by:

getMasterOutput in interface Pty

Returns:

the master's output stream

doGetSlaveInput

protected InputStream doGetSlaveInput()
                               throws IOException

Specified by:

doGetSlaveInput in class AbstractPty

Throws:

IOException

getSlaveOutput

public OutputStream getSlaveOutput()
                            throws IOException

Description copied from interface: Pty

Returns the output stream for the slave side of the PTY.

Data written to this stream will be available for reading from the master's input stream. Processes running in the terminal write to this stream to produce their output.

Specified by:

getSlaveOutput in interface Pty

Returns:

the slave's output stream

Throws:

IOException - if an I/O error occurs

getAttr

public Attributes getAttr()
                   throws IOException

Description copied from interface: Pty

Returns the current terminal attributes for this PTY.

Terminal attributes control various aspects of terminal behavior, such as echo settings, line discipline, and control characters.

Specified by:

getAttr in interface Pty

Returns:

the current terminal attributes

Throws:

IOException - if an I/O error occurs

See Also:

• Attributes

doSetAttr

protected void doSetAttr(Attributes attr)
                  throws IOException

Specified by:

doSetAttr in class AbstractPty

Throws:

IOException

getFlagsToSet

protected List<String> getFlagsToSet(Attributes attr,
 Attributes current)

getSize

public Size getSize()
             throws IOException

Description copied from interface: Pty

Returns the current size (dimensions) of this PTY.

The size includes the number of rows and columns in the terminal window.

Specified by:

getSize in interface Pty

Returns:

the current terminal size

Throws:

IOException - if an I/O error occurs

See Also:

• Size

doGetConfig

protected String doGetConfig()
                      throws IOException

Throws:

IOException

doGetAttr

public static Attributes doGetAttr(String cfg)
                            throws IOException

Throws:

IOException

setSize

public void setSize(Size size)
             throws IOException

Description copied from interface: Pty

Sets the size (dimensions) of this PTY.

This method changes the number of rows and columns in the terminal window. When the size changes, a SIGWINCH signal is typically sent to processes running in the terminal.

Specified by:

setSize in interface Pty

Parameters:

size - the new terminal size to set

Throws:

IOException - if an I/O error occurs

See Also:

• Size

toString

public String toString()

Overrides:

toString in class Object