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Class java.awt.swing.text.JTextComponent

java.lang.Object
    |
    +----java.awt.Component
            |
            +----java.awt.Container
                    |
                    +----java.awt.swing.JComponent
                            |
                            +----java.awt.swing.text.JTextComponent
Subclasses:
JEditorPane, JTextArea, JTextField

public abstract class JTextComponent
extends JComponent
implements Scrollable, Accessible

JTextComponent is the base class for swing text components. It tries to be compatible with the java.awt.TextComponent class where it can reasonably do so. Also provided are other services for additional flexibility (beyond the pluggable UI and bean support).

Caret Changes
The caret is a pluggable object in swing text components. Notification of changes to the caret position and the selection are sent to implementations of the CaretListener interface that have been registered with the text component. The UI will install a default caret unless a customized caret has been set.
Commands

Text components provide a number of commands that can be used to manipulate the component. This is essentially the way that the component expresses it's capabilities. These are expressed in terms of the swing Action interface, using the TextAction implementation. The set of commands supported by the text component can be found with the getActions method. These actions can be bound to key events, fired from buttons, etc.

Keymaps

To facilitate flexible use of the keyboard, support for creating keymaps and binding various keystrokes to some kind of action is provided. In order to allow keymaps to be shared across multiple text components, they can use actions that extend TextAction. TextAction can determine which JTextComponent most recently has or had focus and therefore is the subject of the action (In the case that the ActionEvent sent to the action doesn't contain the target text component as it's source).

The use of the keymap is encouraged, but backward compatibilty with the awt mechanism is provided by giving the listeners a chance to steal the event by consuming it. Keyboard event distribution is handled the following order, with each distribution capable of consuming the event.

  1. focus manager
  2. registered KeyListener's
  3. keymap handling using the current keymap
  4. keyboard handling in JComponent (eg accelerators, component navigation, etc).

By default the component will create a keymap (named DEFAULT_KEYMAP) that is shared by all JTextComponent instances as the default keymap. Typically a look-and-feel implementation will install a different keymap that resolves to the default keymap for those bindings not found in the different keymap. The minimal bindings include:

Model/View Split

The text components have a model-view split. A text component pulls together the objects used to represent the model, view, and controller. The text document model may be shared by other views which act as observers of the model (eg. a document may be shared by multiple components).

The model is defined by the Document interface. This is intended to provide a flexible text storage mechanism that tracks change during edits and can be extended to more sophisticated models. The model interfaces are meant to capture the capabilities of expression given by SGML, a system used to express a wide variety of content. Changes to the model are sent in the form of a Each modification to the document causes notification of the details of the change to be sent to all observers in the form of a DocumentEvent which allows the views to stay up to date with the model. This event is sent to observers that have implemented the DocumentListener interface and registered interest with the model being observed.

Location Information
The capability of determining the location of text in the view is provided. There are two methods, modelToView and viewToModel for determining this information.
Undo/Redo support
Support of an edit history mechanism is provided to allow undo/redo operations. The text component does not itself provide the history buffer by default, but does provide the UndoableEdit records that can be used in conjunction with a history buffer to provide the undo/redo support. The support is provided by the Document model, which allows one to attach UndoableEditListener implementations.
Thread Safety
The swing text components provide some support of thread safe operations. Because of the high level of configurability of the text components, it is possible to circumvent the protection provided. The protection primarily comes from the model, so the documentation of AbstractDocument describes the assumptions of the protection provided. The methods that are safe to call asynchronously are marked with comments.

Warning: serialized objects of this class will not be compatible with future swing releases. The current serialization support is appropriate for short term storage or RMI between Swing1.0 applications. It will not be possible to load serialized Swing1.0 objects with future releases of Swing. The JDK1.2 release of Swing will be the compatibility baseline for the serialized form of Swing objects.

See Also:
Document, DocumentEvent, DocumentListener, Caret, CaretEvent, CaretListener, java.awt.swing.plaf.TextUI, View, ViewFactory

Inner Class Summary
 JTextComponent.AccessibleJTextComponent
Accessibility implementation for JTextComponent

Warning: serialized objects of this class will not be compatible with future swing releases.

static   JTextComponent.KeyBinding
Binding record for creating key bindings

Warning: serialized objects of this class will not be compatible with future swing releases.

 
Inner classes inherited from class java.awt.swing.JComponent
 JComponent.AccessibleJComponent
 

Field Summary
static String  DEFAULT_KEYMAP
This is the name of the default keymap that will be shared by all JTextComponent instances unless they have had a different keymap set.
static String  FOCUS_ACCELERATOR_KEY
The bound property name for the focus accelerator.
 
Fields inherited from class java.awt.swing.JComponent
 accessibleContext, listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW
 
Fields inherited from class java.awt.Component
 BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
 

Constructor Summary
 JTextComponent()
Creates a new JTextComponent.
 

Method Summary
void  addCaretListener(CaretListener listener)
Adds a caret listener for notification of any changes to the caret.
static Keymap  addKeymap(String nm, Keymap parent)
Adds a new keymap into the keymap hierarchy.
void  copy()
Transfers the currently selected range in the associated text model to the system clipboard, leaving the contents in the text model.
void  cut()
Transfers the currently selected range in the associated text model to the system clipboard, removing the contents from the model.
void  fireCaretUpdate(CaretEvent e)
Notifies all listeners that have registered interest for notification on this event type.
AccessibleContext  getAccessibleContext()
Get the AccessibleContext associated with this JComponent
Action[]  getActions()
Fetches the command list for the editor.
Caret  getCaret()
Fetches the cursor that allows text-oriented navigation over the view.
Color  getCaretColor()
Fetches the current color used to render the caret.
int  getCaretPosition()
Returns the position of the text insertion caret for the text component.
Color  getDisabledTextColor()
Fetches the current color used to render the selected text.
Document  getDocument()
Fetches the model associated with the editor.
char  getFocusAccelerator()
Returns the key accelerator that will cause the receiving text component to get the focus.
Highlighter  getHighlighter()
Fetches the object responsible for making highlights.
Keymap  getKeymap()
Fetches the keymap being used by the controller
static Keymap  getKeymap(String nm)
Fetches a named keymap previously added to the document.
Insets  getMargin()
Returns the margin between the text component's border and its text.
Dimension  getPreferredScrollableViewportSize()
Returns the preferred size of the viewport for a view component.
int  getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction)
Components that display logical rows or columns should compute the scroll increment that will completely expose one block of rows or columns, depending on the value of orientation.
boolean  getScrollableTracksViewportHeight()
Return true if a viewport should always force the height of this Scrollable to match the height of the viewport.
boolean  getScrollableTracksViewportWidth()
Return true if a viewport should always force the width of this Scrollable to match the width of the viewport.
int  getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction)
Components that display logical rows or columns should compute the scroll increment that will completely expose one new row or column, depending on the value of orientation.
String  getSelectedText()
Returns the selected text contained in this TextComponent.
Color  getSelectedTextColor()
Fetches the current color used to render the selected text.
Color  getSelectionColor()
Fetches the current color used to render the selection.
int  getSelectionEnd()
Returns the selected text's end position.
int  getSelectionStart()
Returns the selected text's start position.
String  getText(int offs, int len)
Fetches a portion of the text represented by the component.
String  getText()
Returns the text contained in this TextComponent.
java.awt.swing.plaf.TextUI  getUI()
Fetches the user-interface factory for this text-oriented editor.
boolean  isEditable()
Returns the boolean indicating whether this TextComponent is editable or not.
boolean  isFocusTraversable()
Returns true if the focus can be traversed.
boolean  isOpaque()
Returns true if this component is completely opaque.
static void  loadKeymap(Keymap map, JTextComponent.KeyBinding[] bindings, Action[] actions)

Loads a keymap with a bunch of bindings.

Rectangle  modelToView(int pos)
Converts the given location in the model to a place in the view coordinate system.
void  moveCaretPosition(int pos)
Moves the caret to a new position, leaving behind a mark defined by the last time setCaretPosition was called.
void  paste()
Transfers the contents of the system clipboard into the associated text model.
void  processComponentKeyEvent(KeyEvent e)
Process any key events that the component itself recognizes.
void  read(Reader in, Object desc)
Initialize from a stream.
void  removeCaretListener(CaretListener listener)
Removes a caret listener.
static Keymap  removeKeymap(String nm)
Removes a named keymap previously added to the document.
void  replaceSelection(String content)
Replaces the currently selected content with new content represented by the given string.
void  select(int selectionStart, int selectionEnd)
Selects the text found between the specified start and end locations.
void  selectAll()
Selects all the text in the TextComponent.
void  setCaret(Caret c)
Sets the caret to be used.
void  setCaretColor(Color c)
Sets the current color used to render the caret.
void  setCaretPosition(int position)
Sets the position of the text insertion caret for the TextComponent.
void  setDisabledTextColor(Color c)
Sets the current color used to render the disabled text.
void  setDocument(Document doc)
Associates the editor with a text document.
void  setEditable(boolean b)
Sets the specified boolean to indicate whether or not this TextComponent should be editable.
void  setFocusAccelerator(char aKey)
Sets the key accelerator that will cause the receiving text component to get the focus.
void  setHighlighter(Highlighter h)
Sets the highlighter to be used.
void  setKeymap(Keymap map)
Sets the keymap to use for binding events to actions.
void  setMargin(Insets m)
Sets margin space between the text component's border and its text.
void  setOpaque(boolean o)
Sets whether or not the UI should render a background.
void  setSelectedTextColor(Color c)
Sets the current color used to render the selected text.
void  setSelectionColor(Color c)
Sets the current color used to render the selection.
void  setSelectionEnd(int selectionEnd)
Sets the selection end to the specified position.
void  setSelectionStart(int selectionStart)
Sets the selection start to the specified position.
void  setText(String t)
Sets the text of this TextComponent to the specified text.
void  setUI(java.awt.swing.plaf.TextUI ui)
Sets the user-interface factory for this text-oriented editor
void  updateUI()
Reloads the pluggable UI.
int  viewToModel(Point pt)
Converts the given place in the view coordinate system to the nearest representative location in the model.
void  write(Writer out)
Stores the contents of the model into the given stream.
 
Methods inherited from class java.awt.swing.JComponent
 addAncestorListener, addNotify, addPropertyChangeListener, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getAccessibleContext, getActionForKeyStroke, getAlignmentX, getAlignmentY, getAutoscrolls, getBorder, getBounds, getClientProperty, getComponentGraphics, getConditionForKeyStroke, getDebugGraphicsOptions, getGraphics, getHeight, getInsets, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getUIClassID, getVisibleRect, getWidth, getX, getY, grabFocus, hasFocus, isDoubleBuffered, isFocusCycleRoot, isFocusTraversable, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, processComponentKeyEvent, processFocusEvent, processKeyEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removePropertyChangeListener, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setAlignmentX, setAlignmentY, setAutoscrolls, setBorder, setBounds, setDebugGraphicsOptions, setDoubleBuffered, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setUI, setVisible, unregisterKeyboardAction, update, updateUI
 
Methods inherited from class java.awt.Container
 add, add, add, add, add, addContainerListener, addImpl, addNotify, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getAlignmentX, getAlignmentY, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getInsets, getLayout, getMaximumSize, getMinimumSize, getPreferredSize, insets, invalidate, isAncestorOf, layout, list, list, locate, minimumSize, paint, paintComponents, paramString, preferredSize, print, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, removeNotify, setLayout, update, validate, validateTree
 
Methods inherited from class java.awt.Component
 action, add, addComponentListener, addFocusListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addNotify, addPropertyChangeListener, addPropertyChangeListener, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, enableInputMethods, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBounds, getColorModel, getComponentAt, getComponentAt, getCursor, getDropTarget, getFont, getFontMetrics, getForeground, getGraphics, getHeight, getInputContext, getInputMethodRequests, getLocale, getLocation, getLocationOnScreen, getMaximumSize, getMinimumSize, getName, getParent, getPeer, getPreferredSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isDisplayable, isEnabled, isFocusTraversable, isLightweight, isOpaque, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, minimumSize, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paint, paintAll, paramString, postEvent, preferredSize, prepareImage, prepareImage, print, printAll, processComponentEvent, processEvent, processFocusEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, remove, removeComponentListener, removeFocusListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, reshape, resize, resize, setBackground, setBounds, setBounds, setCursor, setDropTarget, setEnabled, setFont, setForeground, setLocale, setLocation, setLocation, setName, setSize, setSize, setVisible, show, show, size, toString, transferFocus, update, validate
 
Methods inherited from class java.lang.Object
 clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

FOCUS_ACCELERATOR_KEY

public static final String FOCUS_ACCELERATOR_KEY
The bound property name for the focus accelerator.

DEFAULT_KEYMAP

public static final String DEFAULT_KEYMAP
This is the name of the default keymap that will be shared by all JTextComponent instances unless they have had a different keymap set.
Constructor Detail

JTextComponent

public JTextComponent()
Creates a new JTextComponent.
Method Detail

getUI

public java.awt.swing.plaf.TextUI getUI()
Fetches the user-interface factory for this text-oriented editor.
Returns:
the factory

setUI

public void setUI(java.awt.swing.plaf.TextUI ui)
Sets the user-interface factory for this text-oriented editor
Parameters:
ui - the factory

updateUI

public void updateUI()
Reloads the pluggable UI. The key used to fetch the new interface is getUIClassID(). The type of the UI is TextUI.
Overrides:
updateUI in class JComponent

isOpaque

public boolean isOpaque()
Returns true if this component is completely opaque.
Returns:
true if this component is completely opaque.
Overrides:
isOpaque in class JComponent

setOpaque

public void setOpaque(boolean o)
Sets whether or not the UI should render a background.
Parameters:
o - true if should render a background
Overrides:
setOpaque in class JComponent

addCaretListener

public void addCaretListener(CaretListener listener)
Adds a caret listener for notification of any changes to the caret.
Parameters:
listener - the listener
See Also:
CaretEvent

removeCaretListener

public void removeCaretListener(CaretListener listener)
Removes a caret listener.
Parameters:
listener - the listener
See Also:
CaretEvent

fireCaretUpdate

protected void fireCaretUpdate(CaretEvent e)
Notifies all listeners that have registered interest for notification on this event type. The event instance is lazily created using the parameters passed into the fire method.
Parameters:
e - the event
See Also:
EventListenerList

setDocument

public void setDocument(Document doc)
Associates the editor with a text document. The currently registered factory is used to build a view for the document, which gets displayed by the editor.
Parameters:
doc - the document to display/edit
See Also:
getDocument

getDocument

public Document getDocument()
Fetches the model associated with the editor. This is primarily for the UI to get at the minimal amount of state required to be a text editor. Subclasses will return the actual type of the model which will typically be something that extends Document.
Returns:
the model

getActions

public Action[] getActions()
Fetches the command list for the editor. This is the list of commands supported by the plugged-in UI augmented by the collection of commands that the editor itself supports. These are useful for binding to events, such as in a keymap.
Returns:
the command list

setMargin

public void setMargin(Insets m)
Sets margin space between the text component's border and its text. Setting it to null will cause the text component to use a default margin. The text component's default Border object will use this value to create the proper margin. However, if a non-default border is set on the text component, it is that Border object's responsibility to create the appropriate margin space (else this property will effectively be ignored).
Parameters:
m - the space between the border and the text

getMargin

public Insets getMargin()
Returns the margin between the text component's border and its text.
Returns:
the margin

getCaret

public Caret getCaret()
Fetches the cursor that allows text-oriented navigation over the view.
Returns:
the cursor

setCaret

public void setCaret(Caret c)
Sets the caret to be used. By default this will be set by the UI that gets installed. This can be changed to a custom caret if desired.
Parameters:
c - the caret
See Also:
getCaret

getHighlighter

public Highlighter getHighlighter()
Fetches the object responsible for making highlights.
Returns:
the highlighter

setHighlighter

public void setHighlighter(Highlighter h)
Sets the highlighter to be used. By default this will be set by the UI that gets installed. This can be changed to a custom highlighter if desired.
Parameters:
h - the highlighter
See Also:
getHighlighter

setKeymap

public void setKeymap(Keymap map)
Sets the keymap to use for binding events to actions.
Parameters:
map - the keymap
See Also:
getKeymap

getKeymap

public Keymap getKeymap()
Fetches the keymap being used by the controller
Returns:
the keymap

addKeymap

public static Keymap addKeymap(String nm,
                               Keymap parent)
Adds a new keymap into the keymap hierarchy. Keymap bindings resolve from bottom up so an attribute specified in a child will override an attribute specified in the parent.
Parameters:
nm - the name of the keymap (must be unique within the collection of named keymaps in the document). The name may be null if the keymap is unnamed, but the caller is responsible for managing the reference returned as an unnamed keymap can't be fetched by name.
parent - the parent keymap. This may be null if unspecified bindings need not be resolved in some other keymap.
Returns:
the keymap

removeKeymap

public static Keymap removeKeymap(String nm)
Removes a named keymap previously added to the document.
Parameters:
nm - the name of the keymap to remove
Returns:
the keymap

getKeymap

public static Keymap getKeymap(String nm)
Fetches a named keymap previously added to the document.
Parameters:
nm - the name of the keymap
Returns:
the keymap

loadKeymap

public static void loadKeymap(Keymap map,
                              JTextComponent.KeyBinding[] bindings,
                              Action[] actions)

Loads a keymap with a bunch of bindings. This can be used to take a static table of definitions and load them into some keymap. The following example illustrates an example of binding some keys to the cut, copy, and paste actions associated with a JTextComponent. It also binds tab to insert the tab into the text component. A code fragment to accomplish this might look as follows:

    JTextComponent c = new JTextPane();
    Keymap k = c.getKeymap();
    JTextComponent.loadKeymap(k, c.getActions(), defaultBindings);
  
    static final JTextComponent.KeyBinding[] defaultBindings = {
      new JTextComponent.KeyBinding(
        KeyStroke.getKeyStroke(KeyEvent.VK_C, InputEvent.CTRL_MASK),
        JTextComponent.copyAction),
      new JTextComponent.KeyBinding(
        KeyStroke.getKeyStroke(KeyEvent.VK_V, InputEvent.CTRL_MASK),
        JTextComponent.pasteAction),
      new JTextComponent.KeyBinding(
        KeyStroke.getKeyStroke(KeyEvent.VK_X, InputEvent.CTRL_MASK),
        JTextComponent.cutAction),
      new JTextComponent.KeyBinding(
        KeyStroke.getKeyStroke('\t'),
        JTextComponent.insertContentAction)
    };
 
Parameters:
map - the keymap
bindings - the bindings
actions - the set of actions

getCaretColor

public Color getCaretColor()
Fetches the current color used to render the caret.
Returns:
the color

setCaretColor

public void setCaretColor(Color c)
Sets the current color used to render the caret.
Parameters:
c - the color
See Also:
getCaretColor

getSelectionColor

public Color getSelectionColor()
Fetches the current color used to render the selection.
Returns:
the color

setSelectionColor

public void setSelectionColor(Color c)
Sets the current color used to render the selection.
Parameters:
c - the color
See Also:
getSelectionColor

getSelectedTextColor

public Color getSelectedTextColor()
Fetches the current color used to render the selected text.
Returns:
the color

setSelectedTextColor

public void setSelectedTextColor(Color c)
Sets the current color used to render the selected text.
Parameters:
c - the color
See Also:
getSelectedTextColor

getDisabledTextColor

public Color getDisabledTextColor()
Fetches the current color used to render the selected text.
Returns:
the color

setDisabledTextColor

public void setDisabledTextColor(Color c)
Sets the current color used to render the disabled text.
Parameters:
c - the color
See Also:
getDisabledTextColor

replaceSelection

public void replaceSelection(String content)
Replaces the currently selected content with new content represented by the given string. If there is no selection this amounts to an insert of the given text. If there is no replacement text this amounts to a removal of the current selection.

This is the method that is used by the default implementation of the action for inserting content that gets bound to the keymap actions.

This method is thread safe, although most Swing methods are not. Please see Threads and Swing for more information.

Parameters:
content - the content to replace the selection with

getText

public String getText(int offs,
                      int len) throws BadLocationException
Fetches a portion of the text represented by the component.
Parameters:
offs - the offset
len - the length
Returns:
the text
Throws:
BadLocationException - of the offset or length are invalid

modelToView

public Rectangle modelToView(int pos) throws BadLocationException
Converts the given location in the model to a place in the view coordinate system.
Parameters:
pos - the position
Returns:
the coordinates as a rectangle
Throws:
BadLocationException - if the given position does not represent a valid location in the associated document
See Also:
modelToView

viewToModel

public int viewToModel(Point pt)
Converts the given place in the view coordinate system to the nearest representative location in the model.
Parameters:
pt - the location in the view to translate
Returns:
the offset from the start of the document
See Also:
viewToModel

cut

public void cut()
Transfers the currently selected range in the associated text model to the system clipboard, removing the contents from the model. The current selection is reset.

copy

public void copy()
Transfers the currently selected range in the associated text model to the system clipboard, leaving the contents in the text model. The current selection is remains intact.

paste

public void paste()
Transfers the contents of the system clipboard into the associated text model. If there is a selection in the associated view, it is replaced with the contents of the clipboard. If there is no selection, the clipboard contents are inserted in front of the current insert position in the associated view.
See Also:
replaceSelection

moveCaretPosition

public void moveCaretPosition(int pos)
Moves the caret to a new position, leaving behind a mark defined by the last time setCaretPosition was called. This forms a selection.
Parameters:
pos - the position
See Also:
setCaretPosition

setFocusAccelerator

public void setFocusAccelerator(char aKey)
Sets the key accelerator that will cause the receiving text component to get the focus. The accelerator will be the key combination of the alt key and the character given. By default, there is no focus accelerator key.
Parameters:
aKey - the key
See Also:
getFocusAccelerator

getFocusAccelerator

public char getFocusAccelerator()
Returns the key accelerator that will cause the receiving text component to get the focus. Return '\0' if no focus accelerator has been set.
Returns:
the key

read

public void read(Reader in,
                 Object desc) throws IOException
Initialize from a stream. This creates a model of the type appropriate for the component and initializes the model from the stream. By default this will load the model as plain text.
Parameters:
in - The stream to read from
desc - An object describing the stream. This might be a string, a File, a URL, etc. Some kinds of documents (such as html for example) might be able to make use of this information.
Throws:
IOException - as thrown by the stream being used to initialize.
See Also:
createDefaultDocument, setDocument, PlainDocument

write

public void write(Writer out) throws IOException
Stores the contents of the model into the given stream. By default this will store the model as plain text.
Parameters:
out - the output stream
Throws:
IOException - on any I/O error

isFocusTraversable

public boolean isFocusTraversable()
Returns true if the focus can be traversed.
Returns:
true if the focus is traversable
Overrides:
isFocusTraversable in class JComponent

processComponentKeyEvent

protected void processComponentKeyEvent(KeyEvent e)
Process any key events that the component itself recognizes. This will be called after the focus manager and any interested listeners have been given a chance to steal away the event. This method will only be called is the event has not yet been consumed. This method is called prior to the keyboard UI logic.

This is implemented to do nothing. Subclasses would normally override this method if they process some key events themselves. If the event is processed, it should be consumed.

Parameters:
e - the event
Overrides:
processComponentKeyEvent in class JComponent

setCaretPosition

public void setCaretPosition(int position)
Sets the position of the text insertion caret for the TextComponent. Note that the caret tracks change, so this may move if the underlying text of the component is changed.
Parameters:
position - the position
Throws:
IllegalArgumentException - if position is less than 0 or greater than the length of the associated document

getCaretPosition

public int getCaretPosition()
Returns the position of the text insertion caret for the text component.
Returns:
the position of the text insertion caret for the text component

setText

public void setText(String t)
Sets the text of this TextComponent to the specified text.

This method is thread safe, although most Swing methods are not. Please see Threads and Swing for more information.

Parameters:
t - the new text to be set
See Also:
getText

getText

public String getText()
Returns the text contained in this TextComponent.
Returns:
the text
See Also:
setText

getSelectedText

public String getSelectedText()
Returns the selected text contained in this TextComponent.
Returns:
the text
Throws:
IllegalArgumentException - if the selection doesn't have a valid mapping into the document for some reason
See Also:
setText

isEditable

public boolean isEditable()
Returns the boolean indicating whether this TextComponent is editable or not.
Returns:
the boolean value
See Also:
setEditable

setEditable

public void setEditable(boolean b)
Sets the specified boolean to indicate whether or not this TextComponent should be editable.
Parameters:
b - the boolean to be set
See Also:
isEditable

getSelectionStart

public int getSelectionStart()
Returns the selected text's start position.
Returns:
the start position

setSelectionStart

public void setSelectionStart(int selectionStart)
Sets the selection start to the specified position. The new starting point is constrained to be before or at the current selection end.

This is available for backward compatiblitity to code that called this method on java.awt.TextComponent. This is implemented to forward to the Caret implementation which is where the actual selection is maintained.

Parameters:
selectionStart - the start position of the text

getSelectionEnd

public int getSelectionEnd()
Returns the selected text's end position.
Returns:
the end position

setSelectionEnd

public void setSelectionEnd(int selectionEnd)
Sets the selection end to the specified position. The new end point is constrained to be at or after the current selection start.

This is available for backward compatiblitity to code that called this method on java.awt.TextComponent. This is implemented to forward to the Caret implementation which is where the actual selection is maintained.

Parameters:
selectionEnd - the start position of the text

select

public void select(int selectionStart,
                   int selectionEnd)
Selects the text found between the specified start and end locations. This call is provided for backward compatibility. It is routed to a call to setCaretPosition followed by a call to moveCaretPostion. The preferred way to manage selection is by calling those methods directly.
Parameters:
selectionStart - the start position of the text
selectionEnd - the end position of the text
See Also:
setCaretPosition, moveCaretPosition

selectAll

public void selectAll()
Selects all the text in the TextComponent.

getPreferredScrollableViewportSize

public Dimension getPreferredScrollableViewportSize()
Returns the preferred size of the viewport for a view component. This is implemented to do the default behavior of returning the preferred size of the component.
Implements:
getPreferredScrollableViewportSize in interface Scrollable
Returns:
The preferredSize of a JViewport whose view is this Scrollable.

getScrollableUnitIncrement

public int getScrollableUnitIncrement(Rectangle visibleRect,
                                      int orientation,
                                      int direction)
Components that display logical rows or columns should compute the scroll increment that will completely expose one new row or column, depending on the value of orientation. Ideally, components should handle a partially exposed row or column by returning the distance required to completely expose the item.

The default implementation of this is to simply return 10% of the visible area. Subclasses are likely to be able to provide a much more reasonable value.

Implements:
getScrollableUnitIncrement in interface Scrollable
Parameters:
visibleRect - The view area visible within the viewport
orientation - Either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL.
direction - Less than zero to scroll up/left, greater than zero for down/right.
Returns:
The "unit" increment for scrolling in the specified direction
See Also:
setUnitIncrement

getScrollableBlockIncrement

public int getScrollableBlockIncrement(Rectangle visibleRect,
                                       int orientation,
                                       int direction)
Components that display logical rows or columns should compute the scroll increment that will completely expose one block of rows or columns, depending on the value of orientation.

The default implementation of this is to simply return the visible area. Subclasses will likely be able to provide a much more reasonable value.

Implements:
getScrollableBlockIncrement in interface Scrollable
Parameters:
visibleRect - The view area visible within the viewport
orientation - Either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL.
direction - Less than zero to scroll up/left, greater than zero for down/right.
Returns:
The "block" increment for scrolling in the specified direction.
See Also:
setBlockIncrement

getScrollableTracksViewportWidth

public boolean getScrollableTracksViewportWidth()
Return true if a viewport should always force the width of this Scrollable to match the width of the viewport. For example a noraml text view that supported line wrapping would return true here, since it would be undesirable for wrapped lines to disappear beyond the right edge of the viewport. Note that returning true for a Scrollable whose ancestor is a JScrollPane effectively disables horizontal scrolling.

Scrolling containers, like JViewport, will use this method each time they are validated.

Implements:
getScrollableTracksViewportWidth in interface Scrollable
Returns:
True if a viewport should force the Scrollables width to match its own.

getScrollableTracksViewportHeight

public boolean getScrollableTracksViewportHeight()
Return true if a viewport should always force the height of this Scrollable to match the height of the viewport. For example a columnar text view that flowed text in left to right columns could effectively disable vertical scrolling by returning true here.

Scrolling containers, like JViewport, will use this method each time they are validated.

Implements:
getScrollableTracksViewportHeight in interface Scrollable
Returns:
True if a viewport should force the Scrollables height to match its own.

getAccessibleContext

public AccessibleContext getAccessibleContext()
Get the AccessibleContext associated with this JComponent
Implements:
getAccessibleContext in interface Accessible
Returns:
the AccessibleContext of this JComponent
Overrides:
getAccessibleContext in class JComponent

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