Package org.jline.builtins

Class ScreenTerminal

java.lang.Object

org.jline.builtins.ScreenTerminal

All Implemented Interfaces:

Sized

Direct Known Subclasses:

WebTerminal.WebTerminalComponent

public class ScreenTerminal
extends Object
implements Sized

A virtual terminal screen implementation.

This class provides a virtual terminal screen that can process ANSI escape sequences and maintain the state of a terminal display. It supports features including:

• Cursor positioning and movement
• Text attributes (bold, underline, etc.)
• Color support (including 256 colors)
• Screen clearing and scrolling
• Alternate screen buffer
• Screen resizing

This implementation is based on the Apache Karaf WebConsole Gogo plugin, with adaptations to support alternate screen, resizing, and 256 colors. It follows the ECMA-48 standard for terminal control sequences.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	MAX_SIZE
static final int	MIN_SIZE

Constructor Summary

Constructors

Constructor	Description
ScreenTerminal()	Creates a ScreenTerminal using the default size of 80 columns and 24 rows.
ScreenTerminal(int columns, int rows)	Creates a ScreenTerminal with the specified number of columns and rows.

Method Summary

Modifier and Type	Method	Description
String	dump()	Dumps the terminal content as HTML with inline RGB color styles.
void	dump(long[] fullscreen, int[] cursor)	Dumps the raw screen content into a flat array.
void	dump(long[] fullscreen, int ftop, int fleft, int fheight, int fwidth, int[] cursor)
String	dump(long timeout, boolean forceDump)	Dumps the terminal content as HTML with inline RGB color styles.
boolean	dump(long timeout, boolean forceDump, long[] fullscreen, int[] cursor)	Waits for the screen to be dirty, then dumps the raw screen content.
boolean	dump(long timeout, boolean forceDump, long[] fullscreen, int ftop, int fleft, int fheight, int fwidth, int[] cursor)	Waits for the screen to be dirty, then dumps the raw screen content into a subregion.
int	getColumns()	Provide the current number of columns in the terminal.
int	getHeight()	Deprecated. Use getRows() instead.
int	getRows()	Gets the number of rows in the terminal.
int	getWidth()	Deprecated. Use getColumns() instead.
boolean	isDirty()
String	pipe(String d)
String	read()
protected void	setDirty()
boolean	setSize(int columns, int rows)	Deprecated. Use setSize(Sized) instead.
boolean	setSize(Sized sized)	Resize the terminal to the specified columns and rows.
String	toString()
void	waitDirty()
boolean	waitDirty(long timeout)	Waits for the screen to become dirty, up to the given timeout.
boolean	write(CharSequence d)

Methods inherited from class java.lang.Object

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

Field Details

MIN_SIZE

public static final int MIN_SIZE

See Also:

• Constant Field Values

MAX_SIZE

public static final int MAX_SIZE

See Also:

• Constant Field Values

Constructor Details

ScreenTerminal

public ScreenTerminal()

Creates a ScreenTerminal using the default size of 80 columns and 24 rows.

ScreenTerminal

public ScreenTerminal(int columns,
 int rows)

Creates a ScreenTerminal with the specified number of columns and rows.

Parameters:

columns - the number of character columns for the terminal

rows - the number of character rows for the terminal

Method Details

isDirty

public boolean isDirty()

waitDirty

public void waitDirty()
               throws InterruptedException

Throws:

InterruptedException

waitDirty

public boolean waitDirty(long timeout)
                  throws InterruptedException

Waits for the screen to become dirty, up to the given timeout. Uses a while loop to guard against spurious wakeups.

Parameters:

timeout - maximum time to wait in milliseconds; if <= 0, returns immediately

Returns:

true if the screen is dirty

Throws:

InterruptedException - if interrupted while waiting

setDirty

protected void setDirty()

getColumns

public int getColumns()

Provide the current number of columns in the terminal.

Specified by:

getColumns in interface Sized

Returns:

the current number of columns

getRows

public int getRows()

Gets the number of rows in the terminal.

Specified by:

getRows in interface Sized

Returns:

the number of rows

getWidth

@Deprecated
public int getWidth()

Deprecated.

Use getColumns() instead.

Gets the terminal width in characters.

Returns:

the width in characters

getHeight

@Deprecated
public int getHeight()

Deprecated.

Use getRows() instead.

Gets the terminal height in characters.

Returns:

the height in characters

setSize

public boolean setSize(Sized sized)

Resize the terminal to the specified columns and rows.

Parameters:

sized - the new Size whose columns and rows will be applied

Returns:

true if the size was set successfully, false otherwise

setSize

@Deprecated
public boolean setSize(int columns,
 int rows)

Deprecated.

Use setSize(Sized) instead.

Resize the terminal to the given number of columns and rows.

Parameters:

columns - the target number of columns (2–256)

rows - the target number of rows (2–256)

Returns:

`true` if the size was changed; `false` if the requested dimensions are out of range

read

public String read()

pipe

public String pipe(String d)

write

public boolean write(CharSequence d)

dump

public void dump(long[] fullscreen,
 int ftop,
 int fleft,
 int fheight,
 int fwidth,
 int[] cursor)

dump

public void dump(long[] fullscreen,
 int[] cursor)

Dumps the raw screen content into a flat array. The array must be at least columns * rows elements long.

Parameters:

fullscreen - destination array

cursor - 2-element array to receive cursor [x, y], or null

dump

public boolean dump(long timeout,
 boolean forceDump,
 long[] fullscreen,
 int ftop,
 int fleft,
 int fheight,
 int fwidth,
 int[] cursor)
             throws InterruptedException

Waits for the screen to be dirty, then dumps the raw screen content into a subregion.

Parameters:

timeout - maximum time to wait in milliseconds

forceDump - if true, dump even if the screen is not dirty

fullscreen - destination array (must be at least fwidth * fheight)

ftop - top row offset

fleft - left column offset

fheight - number of rows to dump

fwidth - number of columns to dump

cursor - 2-element array to receive cursor [x, y], or null

Returns:

true if the screen was dumped

Throws:

InterruptedException - if interrupted

dump

public boolean dump(long timeout,
 boolean forceDump,
 long[] fullscreen,
 int[] cursor)
             throws InterruptedException

Waits for the screen to be dirty, then dumps the raw screen content.

Parameters:

timeout - maximum time to wait in milliseconds

forceDump - if true, dump even if the screen is not dirty

fullscreen - destination array (must be at least columns * rows)

cursor - 2-element array to receive cursor [x, y], or null

Returns:

true if the screen was dumped

Throws:

InterruptedException - if interrupted

dump

public String dump(long timeout,
 boolean forceDump)
            throws InterruptedException

Dumps the terminal content as HTML with inline RGB color styles.

Parameters:

timeout - maximum time to wait for changes in milliseconds

forceDump - whether to force a dump even if screen is not dirty

Returns:

the terminal content as HTML, or null if no update

Throws:

InterruptedException - if interrupted

dump

public String dump()

Dumps the terminal content as HTML with inline RGB color styles.

Returns:

the terminal content as HTML.

toString

public String toString()

Overrides:

toString in class Object