org.crsh.text
Class VirtualScreen

java.lang.Object
  org.crsh.text.VirtualScreen

All Implemented Interfaces:

Appendable, Screenable, ScreenContext

public class VirtualScreen
extends Object
implements ScreenContext

A virtual screen that can be scrolled. This class is thread safe, as it can be used concurrently by two threads, for example one thread can provide new elements while another thread is repainting the buffer to the screen, both threads can either modify the underlying data structure. Paint could also be called concurrently by two threads, one that just provided a new element and wants to repaint the structure and another that changes the current cursor and asks for a repaint too.

Author:

Julien Viet

Nested Class Summary

private static class

VirtualScreen.Foo

Field Summary

private ArrayList<VirtualScreen.Foo>	buffer .
private int	cursorIndex The cursor index in the chunk at the current cursorOffset.
private int	cursorOffset The cursor offset in the buffer.
private Style	cursorStyle .
private int	cursorX The cursor coordinate.
private int	cursorY The cursor coordinate.
private int	height The cached width and height for the current refresh.
private int	index The absolute offset, index and row.
private int	offset The absolute offset, index and row.
private ScreenContext	out .
private static int	PAINTED
private static int	PAINTING
private static int	REFRESH
private int	row The absolute offset, index and row.
private int	status Do we need to clear screen.
private Style	style The current style for last chunk in the buffer.
private int	width The cached width and height for the current refresh.

Constructor Summary

VirtualScreen(ScreenContext out)

Method Summary

Screenable	append(char c)
Screenable	append(CharSequence s)
Screenable	append(CharSequence csq, int start, int end)
Screenable	append(Style style)
Screenable	cls()
void	flush() Flush the stream.
int	getHeight() Returns the screen height in chars.
int	getWidth() Returns the screen width in chars.
boolean	isPainted()
boolean	isPainting()
boolean	isRefresh()
int	nextPage()
boolean	nextRow()
private Pair<Integer,Integer>	nextRow(int offset, int index, int width)
VirtualScreen	paint() Pain the underlying screen context.
boolean	previousRow()
private int	scroll(int amount)
boolean	update()

Methods inherited from class java.lang.Object

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

Field Detail

width

private int width

The cached width and height for the current refresh.

height

private int height

The cached width and height for the current refresh.

buffer

private final ArrayList<VirtualScreen.Foo> buffer

.

style

private Style style

The current style for last chunk in the buffer.

offset

private int offset

The absolute offset, index and row.

index

private int index

The absolute offset, index and row.

row

private int row

The absolute offset, index and row.

cursorX

private int cursorX

The cursor coordinate.

cursorY

private int cursorY

The cursor coordinate.

cursorOffset

private int cursorOffset

The cursor offset in the buffer.

cursorIndex

private int cursorIndex

The cursor index in the chunk at the current cursorOffset.

cursorStyle

private Style cursorStyle

.

out

private final ScreenContext out

.

status

private int status

Do we need to clear screen.

REFRESH

private static final int REFRESH

See Also:

Constant Field Values

PAINTING

private static final int PAINTING

See Also:

Constant Field Values

PAINTED

private static final int PAINTED

See Also:

Constant Field Values

Constructor Detail

VirtualScreen

public VirtualScreen(ScreenContext out)

Method Detail

getWidth

public int getWidth()

Description copied from interface: ScreenContext

Returns the screen width in chars. When the value is not positive it means the value could not be determined.

Specified by:

getWidth in interface ScreenContext

Returns:

the term width

getHeight

public int getHeight()

Description copied from interface: ScreenContext

Returns the screen height in chars. When the value is not positive it means the value could not be determined.

Specified by:

getHeight in interface ScreenContext

Returns:

the term height

append

public Screenable append(CharSequence s)
                  throws IOException

Specified by:

append in interface Appendable

Throws:

IOException

append

public Screenable append(char c)
                  throws IOException

Specified by:

append in interface Appendable

Throws:

IOException

append

public Screenable append(CharSequence csq,
                         int start,
                         int end)
                  throws IOException

Specified by:

append in interface Appendable

Throws:

IOException

append

public Screenable append(Style style)
                  throws IOException

Specified by:

append in interface Screenable

Throws:

IOException

cls

public Screenable cls()
               throws IOException

Specified by:

cls in interface Screenable

Throws:

IOException

paint

public VirtualScreen paint()
                    throws IOException

Pain the underlying screen context.

Returns:

this screen buffer

Throws:

IOException - any io exception

previousRow

public boolean previousRow()
                    throws IOException

Throws:

IOException

isPainted

public boolean isPainted()

Returns:

true if the buffer is painted

isRefresh

public boolean isRefresh()

Returns:

true if the buffer is stale and needs a full repaint

isPainting

public boolean isPainting()

Returns:

true if the buffer is waiting for input to become painted

nextRow

public boolean nextRow()
                throws IOException

Throws:

IOException

nextPage

public int nextPage()
             throws IOException

Throws:

IOException

scroll

private int scroll(int amount)
            throws IOException

Throws:

IOException

nextRow

private Pair<Integer,Integer> nextRow(int offset,
                                      int index,
                                      int width)

update

public boolean update()
               throws IOException

Throws:

IOException

flush

public void flush()
           throws IOException

Description copied from interface: ScreenContext

Flush the stream.

Specified by:

flush in interface ScreenContext

Throws:

IOException - any io exception