org.zaval.lw
Class LwTextField

java.lang.Object
  |
  +--org.zaval.util.ValidationObject
        |
        +--org.zaval.lw.LwCanvas
              |
              +--org.zaval.lw.LwLabel
                    |
                    +--org.zaval.lw.LwTextField

All Implemented Interfaces:

Cursorable, Drawable, java.util.EventListener, Layoutable, LwComponent, LwFocusListener, LwKeyListener, LwMouseListener, LwMouseMotionListener, PosInfo, PosListener, ScrollObj, TxtSelectionInfo, Validationable

Direct Known Subclasses:

LwMaskTextField

public class LwTextField

extends LwLabel

implements LwKeyListener, LwMouseListener, LwMouseMotionListener, LwFocusListener, Cursorable, PosInfo, PosListener, ScrollObj, TxtSelectionInfo

This class is a text field component. The library provides several text renders implementations that can be used as a face view of the component:

• LwAdvTextRender. This text render is used as default text render.
• LwTextRender. This text render is base for LwAdvTextRender render.
• LwPasswordText. This text render is used for password text fields. The sample below shows the render usage:

          ...
          LwTextFiled tf = new LwTextFiled("Password text");
          tf.getViewMan(true).setView(new LwPasswordText(tf.getText()));
          ...
       

The list below describes some features of the component:

• Use following code to organize single line text field component with a fixed number of characters

          ...
          // Creates single line text field component, where it is possible to
          // enter at most 10 characters.
          LwTextFiled tf = new LwTextFiled("", 10);
          ...
       

• Use setPSByRowsCols method to define preferred size of the component basing on the number of rows and columns. The method calculates and sets preferred size of the text field component according to row size and column size. Draw attention that if the font has been redefined for the text render, than it is necessary to call the method again to recalculate his preferred size.
• It is possible to redefined text cursor view by setCursorView method.
• It is possible to define another pos controller by setPosController method to control text cursor position.
• Use setEditable method to define if a text can be edited or not.
• Use getSelectedText method to get selected text.

The component overrides the getOrigin method to organize scrolling of the content. The scrolling mechanism works right if the component will be inserted into a LwScrollPan component.

To listen when the cursor position has been changed use the pos controller as follow:

   public class Sample
   implements PosListener
   {
     ...
     public void init()
     {
       ...
       LwTextFiled tf = new LwTextFiled("Text");
       tf.getPosController().addPosListener(this);
       ...
     }
     public void posChanged(PosEvent e) {
       System.out.println("The old cursor location is - " + e.getPrevOffset());
     }
   }
 

Fields inherited from class org.zaval.lw.LwCanvas

bits, height, insets, parent, psHeight, psWidth, skins, width, x, y

Fields inherited from class org.zaval.util.ValidationObject

isValidFlag

Constructor Summary

LwTextField()
Constructs a text filed component with no text.

LwTextField(java.lang.String s)
Constructs a text field component with the specified text.

LwTextField(java.lang.String s, int maxCol)
Constructs a single line text field component with the specified text and the maximal number of columns.

LwTextField(TextModel model)
Constructs a text field component with the specified text model.

Method Summary

boolean	canHaveFocus() Specifies if the component can have focus.
protected void	drawCursor(java.awt.Graphics g) The method is used to paint the text cursor using the cursor view.
void	endDragged(LwMouseMotionEvent e) Invoked when the mouse ends dragged.
static java.awt.Point	findNextWord(TextModel t, int line, int col, int d) Finds starting from the specified line and column next word in the given text model and returns the found word location.
void	focusGained(LwFocusEvent e) Invoked when the light weight component gained focus.
void	focusLost(LwFocusEvent e) Invoked when the light weight component lost focus.
int	getCursorType(LwComponent target, int x, int y) Gets the cursor type for the specified location of the given component.
LwView	getCursorView() Gets the cursor view that is used to paint the text cursor.
java.awt.Point	getEndSelection() Returns the last selection row and column
int	getLines() Gets the number of lines.
int	getLineSize(int i) Gets the line size for the specified line number.
int	getMaxOffset() Gets the maximal offset.
java.awt.Point	getOrigin() Returns an origin of the component.
PosController	getPosController() Gets the pos controller that manages the text cursor position.
java.awt.Dimension	getPreferredSize() Gets the preferred size of this component.
java.awt.Color	getSelectColor() Returns a color that is used to render selected text background.
java.lang.String	getSelectedText() Returns the selected text.
java.awt.Point	getSelectionOffsets() Gets the start and last selection offsets.
java.awt.Point	getSOLocation() Gets the scroll object location.
java.awt.Dimension	getSOSize() Gets the scroll object size.
java.awt.Point	getStartSelection() Returns the start selection row and column
static java.lang.String	getSubString(TextModel t, java.awt.Point start, java.awt.Point end) Returns a substring of the specified text model, at the given start and last position.
static java.awt.Point	getTextLocationAt(LwTextRender render, PosController pos) Calculates and gets a pixel location for the specified text render and the text cursor position.
static java.awt.Point	getTextRowColAt(LwTextRender render, int x, int y) Calculates and gets a text position for the specified text render and the location.
protected boolean	handleKey(LwKeyEvent e) Handles the specified key event.
boolean	hasSelection() Tests if the a text part has been selected.
boolean	isEditable() Checks if the text field component is editable.
protected boolean	isFiltered(LwKeyEvent e) Returns true if the key event should be handle next, returns false if the handling process has to be terminated.
void	keyPressed(LwKeyEvent e) Invoked when a key has been pressed.
void	keyReleased(LwKeyEvent e) Invoked when a key has been released.
void	keyTyped(LwKeyEvent e) Invoked when a key has been typed.
protected LwTextRender	makeTextRender(TextModel t) The method gets default text render that will be used to render the specified text model.
void	mouseClicked(LwMouseEvent e) Invoked when the mouse button has been clicked on a light weight component.
void	mouseDragged(LwMouseMotionEvent e) Invoked when a mouse button is pressed on a component and then dragged.
void	mouseEntered(LwMouseEvent e) Invoked when the mouse enters a light weight component.
void	mouseExited(LwMouseEvent e) Invoked when the mouse exits a light weight component.
void	mouseMoved(LwMouseMotionEvent e) Invoked when the mouse pointer has been moved on a light weight component (with no buttons no down).
void	mousePressed(LwMouseEvent e) Invoked when the mouse button has been pressed on a light weight component.
void	mouseReleased(LwMouseEvent e) Invoked when the mouse button has been released on a light weight component.
boolean	moveContent() Tests if the scroll component performs scrolling by changing it location or view.
protected int	pageSize() Gets the page size.
void	paint(java.awt.Graphics g) Paints this component.
void	posChanged(PosEvent e) Invoked when a virtual position has been changed.
protected void	recalc() Invoked with validate method only if the component is not valid.
protected void	remove(int pos, int size) Removes a part of the text starting from the given position and with the specified size.
void	select(int startOffset, int endOffset) Selects the specified by the start and end offsets the text part.
void	setCursorView(LwView v) Sets the specified cursor view to render the text cursor.
void	setEditable(boolean b) Sets the specified mode for the text field component.
void	setEnabled(boolean b) Enables or disables this component.
void	setPosController(PosController p) Sets the specified pos controller to manage the text cursor position.
void	setPSByRowsCols(int r, int c) Sets the preferred size for the text field component that conforms to the specified number of rows and columns.
void	setScrollMan(ScrollMan m) Sets the specified scroll manager for the scroll object.
void	setSelectColor(java.awt.Color c) Sets the specified color to render selected text.
void	setSOLocation(int x, int y) Sets the specified scroll object location.
void	setText(java.lang.String s) Sets the specified string to be shown with the class.
void	startDragged(LwMouseMotionEvent e) Invoked when the mouse starts dragged.
protected void	stopSelection() Clear the current selection.
protected void	write(int pos, java.lang.String s) Inserts the specified text at the given position.

Methods inherited from class org.zaval.lw.LwLabel

getForeground, getText, getTextModel, getTextRender, setForeground

Methods inherited from class org.zaval.lw.LwCanvas

calcPreferredSize, getBackground, getBounds, getHeight, getInsets, getLocation, getLwComponentAt, getLwParent, getSize, getViewMan, getVisiblePart, getWidth, getX, getY, hasFocus, invalidate, isEnabled, isOpaque, isVisible, repaint, repaint, requestFocus, setBackground, setInsets, setLocation, setLwParent, setOpaque, setPSSize, setSize, setViewMan, setVisible, toString, update, validate, viewManChanged, vrp

Methods inherited from class org.zaval.util.ValidationObject

isValid

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.zaval.util.Validationable

isValid

Constructor Detail

LwTextField

public LwTextField()

Constructs a text filed component with no text.

LwTextField

public LwTextField(java.lang.String s)

Constructs a text field component with the specified text. The methods sets LwAdvTextRender as the face view and sets org.zaval.data.Text as the render target.

Parameters:

s - the specified text.

LwTextField

public LwTextField(java.lang.String s,
                   int maxCol)

Constructs a single line text field component with the specified text and the maximal number of columns.

Parameters:

s - the specified text.

maxCol - the specified maximal number of columns.

LwTextField

public LwTextField(TextModel model)

Constructs a text field component with the specified text model.

Parameters:

model - the specified text model.

Method Detail

canHaveFocus

public boolean canHaveFocus()

Description copied from interface: LwComponent

Specifies if the component can have focus.

Overrides:

canHaveFocus in class LwCanvas

Following copied from interface: org.zaval.lw.LwComponent

Returns:

true if the component can have the focus.

getPosController

public PosController getPosController()

Gets the pos controller that manages the text cursor position.

Returns:

a pos controller.

setPosController

public void setPosController(PosController p)

Sets the specified pos controller to manage the text cursor position.

Parameters:

p - the specified pos controller.

getCursorView

public LwView getCursorView()

Gets the cursor view that is used to paint the text cursor.

Returns:

a cursor view.

setCursorView

public void setCursorView(LwView v)

Sets the specified cursor view to render the text cursor.

Parameters:

v - the specified cursor view.

setPSByRowsCols

public void setPSByRowsCols(int r,
                            int c)

Sets the preferred size for the text field component that conforms to the specified number of rows and columns.

Parameters:

r - the specified number of rows.

c - the specified number of columns.

paint

public void paint(java.awt.Graphics g)

Paints this component. The method initiates painting of the cursor caret by calling drawCursor method.

Overrides:

paint in class LwCanvas

Parameters:

g - the graphics context to be used for painting.

setEditable

public void setEditable(boolean b)

Sets the specified mode for the text field component. The component is editable if it is possible to edit a text.

Parameters:

b - the specified mode. If the mode is true than the component is editable; otherwise not-editable.

isEditable

public boolean isEditable()

Checks if the text field component is editable.

Returns:

true if the text field is editable; false otherwise.

keyPressed

public void keyPressed(LwKeyEvent e)

Description copied from interface: LwKeyListener

Invoked when a key has been pressed.

Specified by:

keyPressed in interface LwKeyListener

Following copied from interface: org.zaval.lw.event.LwKeyListener

Parameters:

e - the specified key event.

keyTyped

public void keyTyped(LwKeyEvent e)

Description copied from interface: LwKeyListener

Invoked when a key has been typed.

Specified by:

keyTyped in interface LwKeyListener

Following copied from interface: org.zaval.lw.event.LwKeyListener

Parameters:

e - the specified key event.

focusGained

public void focusGained(LwFocusEvent e)

Description copied from interface: LwFocusListener

Invoked when the light weight component gained focus.

Specified by:

focusGained in interface LwFocusListener

Following copied from interface: org.zaval.lw.event.LwFocusListener

Parameters:

e - the specified focus event.

focusLost

public void focusLost(LwFocusEvent e)

Description copied from interface: LwFocusListener

Invoked when the light weight component lost focus.

Specified by:

focusLost in interface LwFocusListener

Following copied from interface: org.zaval.lw.event.LwFocusListener

Parameters:

e - the specified focus event.

keyReleased

public void keyReleased(LwKeyEvent e)

Description copied from interface: LwKeyListener

Invoked when a key has been released.

Specified by:

keyReleased in interface LwKeyListener

Following copied from interface: org.zaval.lw.event.LwKeyListener

Parameters:

e - the specified key event.

mouseClicked

public void mouseClicked(LwMouseEvent e)

Description copied from interface: LwMouseListener

Invoked when the mouse button has been clicked on a light weight component.

Specified by:

mouseClicked in interface LwMouseListener

Following copied from interface: org.zaval.lw.event.LwMouseListener

Parameters:

e - the specified mouse event.

mouseEntered

public void mouseEntered(LwMouseEvent e)

Description copied from interface: LwMouseListener

Invoked when the mouse enters a light weight component.

Specified by:

mouseEntered in interface LwMouseListener

Following copied from interface: org.zaval.lw.event.LwMouseListener

Parameters:

e - the specified mouse event.

mouseExited

public void mouseExited(LwMouseEvent e)

Description copied from interface: LwMouseListener

Invoked when the mouse exits a light weight component.

Specified by:

mouseExited in interface LwMouseListener

Following copied from interface: org.zaval.lw.event.LwMouseListener

Parameters:

e - the specified mouse event.

startDragged

public void startDragged(LwMouseMotionEvent e)

Description copied from interface: LwMouseMotionListener

Invoked when the mouse starts dragged.

Specified by:

startDragged in interface LwMouseMotionListener

Following copied from interface: org.zaval.lw.event.LwMouseMotionListener

Parameters:

e - the specified mouse motion event.

endDragged

public void endDragged(LwMouseMotionEvent e)

Description copied from interface: LwMouseMotionListener

Invoked when the mouse ends dragged.

Specified by:

endDragged in interface LwMouseMotionListener

Following copied from interface: org.zaval.lw.event.LwMouseMotionListener

Parameters:

e - the specified mouse motion event.

mouseReleased

public void mouseReleased(LwMouseEvent e)

Description copied from interface: LwMouseListener

Invoked when the mouse button has been released on a light weight component.

Specified by:

mouseReleased in interface LwMouseListener

Following copied from interface: org.zaval.lw.event.LwMouseListener

Parameters:

e - the specified mouse event.

mouseMoved

public void mouseMoved(LwMouseMotionEvent e)

Description copied from interface: LwMouseMotionListener

Invoked when the mouse pointer has been moved on a light weight component (with no buttons no down).

Specified by:

mouseMoved in interface LwMouseMotionListener

Following copied from interface: org.zaval.lw.event.LwMouseMotionListener

Parameters:

e - the specified mouse motion event.

mouseDragged

public void mouseDragged(LwMouseMotionEvent e)

Description copied from interface: LwMouseMotionListener

Invoked when a mouse button is pressed on a component and then dragged. Mouse drag events will continue to be delivered to the component where the first originated until the mouse button is released (regardless of whether the mouse position is within the bounds of the component).

Specified by:

mouseDragged in interface LwMouseMotionListener

Following copied from interface: org.zaval.lw.event.LwMouseMotionListener

Parameters:

e - the specified mouse motion event.

mousePressed

public void mousePressed(LwMouseEvent e)

Description copied from interface: LwMouseListener

Invoked when the mouse button has been pressed on a light weight component.

Specified by:

mousePressed in interface LwMouseListener

Following copied from interface: org.zaval.lw.event.LwMouseListener

Parameters:

e - the specified mouse event.

getCursorType

public int getCursorType(LwComponent target,
                         int x,
                         int y)

Gets the cursor type for the specified location of the given component. The method returns Cursor.TEXT_CURSOR cursor type.

Specified by:

getCursorType in interface Cursorable

Parameters:

target - the given component.

x - the x coordinate.

y - the y coordinate.

Returns:

a cursor type.

getLineSize

public int getLineSize(int i)

Description copied from interface: PosInfo

Gets the line size for the specified line number.

Specified by:

getLineSize in interface PosInfo

Following copied from interface: org.zaval.misc.PosInfo

Parameters:

line - the specified line number.

Returns:

a size of the line.

getLines

public int getLines()

Description copied from interface: PosInfo

Gets the number of lines.

Specified by:

getLines in interface PosInfo

Following copied from interface: org.zaval.misc.PosInfo

Returns:

a number of lines.

getMaxOffset

public int getMaxOffset()

Description copied from interface: PosInfo

Gets the maximal offset. The method can return -1 as the result, in this case the pos controller that uses the pos info will try to calculate the maximal offset itself basing on the line number and the lines sizes.

Specified by:

getMaxOffset in interface PosInfo

Following copied from interface: org.zaval.misc.PosInfo

Returns:

a maximal offset.

setText

public void setText(java.lang.String s)

Description copied from class: LwLabel

Sets the specified string to be shown with the class.

Overrides:

setText in class LwLabel

Following copied from class: org.zaval.lw.LwLabel

Parameters:

s - the specified string.

posChanged

public void posChanged(PosEvent e)

Description copied from interface: PosListener

Invoked when a virtual position has been changed.

Specified by:

posChanged in interface PosListener

Following copied from interface: org.zaval.misc.event.PosListener

Parameters:

e - the specified pos event.

getOrigin

public java.awt.Point getOrigin()

Returns an origin of the component. The method is overrided with the component to offset a content of the text field depending on the cursor position.

Overrides:

getOrigin in class LwCanvas

Returns:

an origin of the component.

getPreferredSize

public java.awt.Dimension getPreferredSize()

Description copied from class: LwCanvas

Gets the preferred size of this component. The method computes the preferred size as a sum of the component insets (returned with getInsets method) and a "pure" preferred size (returned with calcPreferredSize method). You should not override the method, use calcPreferredSize method to define the "pure" preferred size of this component.

Overrides:

getPreferredSize in class LwCanvas

Following copied from class: org.zaval.lw.LwCanvas

Returns:

a dimension object indicating this component preferred size.

getSOLocation

public java.awt.Point getSOLocation()

Description copied from interface: ScrollObj

Gets the scroll object location.

Specified by:

getSOLocation in interface ScrollObj

Following copied from interface: org.zaval.misc.ScrollObj

Returns:

a scroll object location.

setSOLocation

public void setSOLocation(int x,
                          int y)

Description copied from interface: ScrollObj

Sets the specified scroll object location. The method defines a mechanism that will be used to scrool the object.

Specified by:

setSOLocation in interface ScrollObj

Following copied from interface: org.zaval.misc.ScrollObj

Parameters:

x - the specified x coordinate.

y - the specified y coordinate.

getSOSize

public java.awt.Dimension getSOSize()

Description copied from interface: ScrollObj

Gets the scroll object size. The size is a size that the scroll object wants to have.

Specified by:

getSOSize in interface ScrollObj

Following copied from interface: org.zaval.misc.ScrollObj

Returns:

a scroll object size.

setScrollMan

public void setScrollMan(ScrollMan m)

Description copied from interface: ScrollObj

Sets the specified scroll manager for the scroll object. The manager reference should be used with the scroll object to notify when the scroll object has been moved or resized.

Specified by:

setScrollMan in interface ScrollObj

Following copied from interface: org.zaval.misc.ScrollObj

Parameters:

m - the specified scroll manager.

moveContent

public boolean moveContent()

Tests if the scroll component performs scrolling by changing it location or view. The method is overrided with the component to point move a content of the text field, the method always returns true.

Specified by:

moveContent in interface ScrollObj

Returns:

true if the scroll component organizes scrolling by moving its view; otherwise false.

getStartSelection

public java.awt.Point getStartSelection()

Description copied from interface: TxtSelectionInfo

Returns the start selection row and column

Specified by:

getStartSelection in interface TxtSelectionInfo

Following copied from interface: org.zaval.lw.TxtSelectionInfo

Returns:

a start selection row and column. The result is represented using java.awt.Point class where x field is selection row and y field is selection column.

getEndSelection

public java.awt.Point getEndSelection()

Description copied from interface: TxtSelectionInfo

Returns the last selection row and column

Specified by:

getEndSelection in interface TxtSelectionInfo

Following copied from interface: org.zaval.lw.TxtSelectionInfo

Returns:

a last selection row and column. The result is represented using java.awt.Point class where x field is selection row and y field is selection column.

hasSelection

public boolean hasSelection()

Tests if the a text part has been selected.

Returns:

true if the text part has been selected; false otherwise.

getSelectionOffsets

public java.awt.Point getSelectionOffsets()

Gets the start and last selection offsets.

Returns:

the start and last selection offsets. The result is represented with java.awt.Point class where x field corresponds to start selection offset and y field corresponds to last selection offset.

getSelectedText

public java.lang.String getSelectedText()

Description copied from interface: TxtSelectionInfo

Returns the selected text.

Specified by:

getSelectedText in interface TxtSelectionInfo

Following copied from interface: org.zaval.lw.TxtSelectionInfo

Returns:

a selected text. The method returns null if there is not selected text.

getSelectColor

public java.awt.Color getSelectColor()

Description copied from interface: TxtSelectionInfo

Returns a color that is used to render selected text background.

Specified by:

getSelectColor in interface TxtSelectionInfo

Following copied from interface: org.zaval.lw.TxtSelectionInfo

Returns:

the color to render selected text background.

setSelectColor

public void setSelectColor(java.awt.Color c)

Sets the specified color to render selected text.

Parameters:

c - the specified color.

setEnabled

public void setEnabled(boolean b)

Description copied from class: LwCanvas

Enables or disables this component. An enabled component can participate in events handling and performing processes. Component is enabled initially by default. The method performs appropriate LwComponentEvent.

Overrides:

setEnabled in class LwCanvas

Following copied from class: org.zaval.lw.LwCanvas

Parameters:

b - if true, this component is enabled; otherwise this component is disabled.

select

public void select(int startOffset,
                   int endOffset)

Selects the specified by the start and end offsets the text part.

Parameters:

startOffset - the specified start offset.

endOffset - the specified end offset.

drawCursor

protected void drawCursor(java.awt.Graphics g)

The method is used to paint the text cursor using the cursor view.

Parameters:

g - the graphics context to be used for painting.

recalc

protected void recalc()

Description copied from class: LwCanvas

Invoked with validate method only if the component is not valid. The method shoud be overrided to calculate metrical characteristics of the component to minimize computation time of the preferred size for the component. For example, you can calculate a preferred size inside the method and just return it by calcPreferredSize method.

Overrides:

recalc in class LwCanvas

handleKey

protected boolean handleKey(LwKeyEvent e)

Handles the specified key event.

Parameters:

e - the specified key event to be handle.

Returns:

true if the key event has been handled with the method; otherwise false.

isFiltered

protected boolean isFiltered(LwKeyEvent e)

Returns true if the key event should be handle next, returns false if the handling process has to be terminated. The method is called before any other event handler will be executed.

Parameters:

e - the specified key event.

Returns:

true if the key event should be handled.

makeTextRender

protected LwTextRender makeTextRender(TextModel t)

Description copied from class: LwLabel

The method gets default text render that will be used to render the specified text model. The render is set as the face view for the component during the component initialization.

Overrides:

makeTextRender in class LwLabel

Following copied from class: org.zaval.lw.LwLabel

Parameters:

t - the specified text model.

Returns:

a text render that is going to be used as the face view of the component.

remove

protected void remove(int pos,
                      int size)

Removes a part of the text starting from the given position and with the specified size.

Parameters:

pos - the given position.

size - the specified removed part size.

write

protected void write(int pos,
                     java.lang.String s)

Inserts the specified text at the given position.

Parameters:

pos - the given position.

s - the specified text to be inserted.

pageSize

protected int pageSize()

Gets the page size.

Returns:

a page size.

stopSelection

protected void stopSelection()

Clear the current selection.

getTextLocationAt

public static java.awt.Point getTextLocationAt(LwTextRender render,
                                               PosController pos)

Calculates and gets a pixel location for the specified text render and the text cursor position.

Parameters:

render - the specified text render.

pos - the pos controller that defines the text position.

Returns:

a pixel location.

getTextRowColAt

public static java.awt.Point getTextRowColAt(LwTextRender render,
                                             int x,
                                             int y)

Calculates and gets a text position for the specified text render and the location. The result is represented with java.awt.Point class where x field defines a row and y field defines a column.

Parameters:

render - the specified text render.

x - the x coordinate of the location.

y - the y coordinate of the location.

Returns:

a text position.

findNextWord

public static java.awt.Point findNextWord(TextModel t,
                                          int line,
                                          int col,
                                          int d)

Finds starting from the specified line and column next word in the given text model and returns the found word location. The result is represented with java.awt.Point object where x field defines a row text position and y field defines a column text position.

Parameters:

t - the specified text model.

line - the specified starting line.

col - the specified starting column.

d - the specified searching direction. If the value is 1 than the method looks for a next word location, if the value is -1 than the method looks for a previous word location.

Returns:

a word location.

getSubString

public static java.lang.String getSubString(TextModel t,
                                            java.awt.Point start,
                                            java.awt.Point end)

Returns a substring of the specified text model, at the given start and last position. The positions are represented with java.awt.Point object where x field defines a row and y field defines a column.

Parameters:

t - the specified text model.

start - the specified start position.

end - the specified last position.

Returns:

a substring.