Class java.awt.TextComponent

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Java Platform 1.2
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Class java.awt.TextComponent

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.TextComponent

Direct Known Subclasses:: TextArea, TextField

public class TextComponent
extends Component

The TextComponent class is the superclass of any component that allows the editing of some text.

A text component embodies a string of text. The TextComponent class defines a set of methods that determine whether or not this text is editable. If the component is editable, it defines another set of methods that supports a text insertion caret.

In addition, the class defines methods that are used to maintain a current selection from the text. The text selection, a substring of the component's text, is the target of editing operations. It is also referred to as the selected text.

Since:: JDK1.0
See Also:: Serialized Form

Field Summary
protected TextListener	textListener

Fields inherited from class java.awt.Component
BOTTOM_ALIGNMENT , CENTER_ALIGNMENT , LEFT_ALIGNMENT , RIGHT_ALIGNMENT , TOP_ALIGNMENT

Method Summary
void	addTextListener(TextListener l) Adds the specified text event listener to recieve text events from this textcomponent.
int	getCaretPosition() Gets the position of the text insertion caret for this text component.
String	getSelectedText() Gets the selected text from the text that is presented by this text component.
int	getSelectionEnd() Gets the end position of the selected text in this text component.
int	getSelectionStart() Gets the start position of the selected text in this text component.
String	getText() Gets the text that is presented by this text component.
boolean	isEditable() Indicates whether or not this text component is editable.
protected String	paramString() Returns the parameter string representing the state of this text component.
protected void	processEvent(AWTEvent e) Processes events on this textcomponent.
protected void	processTextEvent(TextEvent e) Processes text events occurring on this text component by dispatching them to any registered TextListener objects.
void	removeNotify() Removes the TextComponent's peer.
void	removeTextListener(TextListener l) Removes the specified text event listener so that it no longer receives text events from this textcomponent
void	select(int selectionStart, int selectionEnd) Selects the text between the specified start and end positions.
void	selectAll() Selects all the text in this text component.
void	setCaretPosition(int position) Sets the position of the text insertion caret for this text component.
void	setEditable(boolean b) Sets the flag that determines whether or not this text component is editable.
void	setSelectionEnd(int selectionEnd) Sets the selection end for this text component to the specified position.
void	setSelectionStart(int selectionStart) Sets the selection start for this text component to the specified position.
void	setText(String t) Sets the text that is presented by this text component to be the specified text.

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 , getBounds , getColorModel , getComponentAt , getComponentAt , getComponentOrientation , getCursor , getDropTarget , getFont , getFontMetrics , getForeground , getGraphics , getHeight , getInputContext , getInputMethodRequests , getLocale , getLocation , getLocation , getLocationOnScreen , getMaximumSize , getMinimumSize , getName , getParent , getPeer , getPreferredSize , getSize , getSize , getToolkit , getTreeLock , getWidth , getX , getY , gotFocus , handleEvent , hasFocus , hide , imageUpdate , inside , invalidate , isDisplayable , isDoubleBuffered , 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 , postEvent , preferredSize , prepareImage , prepareImage , print , printAll , processComponentEvent , processFocusEvent , processInputMethodEvent , processKeyEvent , processMouseEvent , processMouseMotionEvent , remove , removeComponentListener , removeFocusListener , removeInputMethodListener , removeKeyListener , removeMouseListener , removeMouseMotionListener , removePropertyChangeListener , removePropertyChangeListener , repaint , repaint , repaint , repaint , requestFocus , reshape , resize , resize , setBackground , setBounds , setBounds , setComponentOrientation , 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 , wait , wait , wait

Field Detail

textListener

protected transient TextListener textListener

Method Detail

removeNotify

public void removeNotify()

Removes the TextComponent's peer. The peer allows us to modify the appearance of the TextComponent without changing its functionality.

Overrides:: removeNotify in class Component

setText

public void setText(String t)

Sets the text that is presented by this text component to be the specified text.

Parameters:: t - the new text.
See Also:: getText()

getText

public String getText()

Gets the text that is presented by this text component.

See Also:: setText(java.lang.String)

getSelectedText

public String getSelectedText()

Gets the selected text from the text that is presented by this text component.

Returns:: the selected text of this text component.
See Also:: select(int, int)

isEditable

public boolean isEditable()

Indicates whether or not this text component is editable.

Returns:: true if this text component is editable; false otherwise.
Since:: JDK1ble
See Also:: setEditable(boolean)

setEditable

public void setEditable(boolean b)

Sets the flag that determines whether or not this text component is editable.

If the flag is set to true, this text component becomes user editable. If the flag is set to false, the user cannot change the text of this text component.

Parameters:: t - a flag indicating whether this text component should be user editable.
See Also:: isEditable()

getSelectionStart

public int getSelectionStart()

Gets the start position of the selected text in this text component.

Returns:: the start position of the selected text.
See Also:: setSelectionStart(int), getSelectionEnd()

setSelectionStart

public void setSelectionStart(int selectionStart)

Sets the selection start for this text component to the specified position. The new start point is constrained to be at or before the current selection end. It also cannot be set to less than zero, the beginning of the component's text. If the caller supplies a value for selectionStart that is out of bounds, the method enforces these constraints silently, and without failure.

Parameters:: selectionStart - the start position of the selected text.
Since:: JDK1.1
See Also:: getSelectionStart(), setSelectionEnd(int)

getSelectionEnd

public int getSelectionEnd()

Gets the end position of the selected text in this text component.

Returns:: the end position of the selected text.
See Also:: setSelectionEnd(int), getSelectionStart()

setSelectionEnd

public void setSelectionEnd(int selectionEnd)

Sets the selection end for this text component to the specified position. The new end point is constrained to be at or after the current selection start. It also cannot be set beyond the end of the component's text. If the caller supplies a value for selectionEnd that is out of bounds, the method enforces these constraints silently, and without failure.

Parameters:: selectionEnd - the end position of the selected text.
Since:: JDK1.1
See Also:: getSelectionEnd(), setSelectionStart(int)

select

public void select(int selectionStart,
                   int selectionEnd)

Selects the text between the specified start and end positions.

This method sets the start and end positions of the selected text, enforcing the restriction that the end position must be greater than or equal to the start position. The start position must be greater than zero, and the end position must be less that or equal to the length of the text component's text. If the caller supplies values that are inconsistent or out of bounds, the method enforces these constraints silently, and without failure.

Parameters:: selectionStart - the start position of the text to select.; selectionEnd - the end position of the text to select.
See Also:: setSelectionStart(int), setSelectionEnd(int), selectAll()

selectAll

public void selectAll()

Selects all the text in this text component.

See Also:

setCaretPosition

public void setCaretPosition(int position)

Sets the position of the text insertion caret for this text component.

Parameters:: position - the position of the text insertion caret.
Throws:: IllegalArgumentException - if the value supplied for position is less than zero.
Since:: JDK1.1

getCaretPosition

public int getCaretPosition()

Gets the position of the text insertion caret for this text component.

Returns:: the position of the text insertion caret.
Since:: JDK1.1

addTextListener

public void addTextListener(TextListener l)

Adds the specified text event listener to recieve text events from this textcomponent.

Parameters:: l - the text event listener

removeTextListener

public void removeTextListener(TextListener l)

Removes the specified text event listener so that it no longer receives text events from this textcomponent

processEvent

protected void processEvent(AWTEvent e)

Processes events on this textcomponent. If the event is a TextEvent, it invokes the processTextEvent method, else it invokes its superclass's processEvent.

Parameters:: e - the event
Overrides:: processEvent in class Component

processTextEvent

protected void processTextEvent(TextEvent e)

Processes text events occurring on this text component by dispatching them to any registered TextListener objects. NOTE: This method will not be called unless text events are enabled for this component; this happens when one of the following occurs: a) A TextListener object is registered via addTextListener() b) Text events are enabled via enableEvents()

Parameters:: e - the text event
See Also:: Component.enableEvents(long)

paramString

protected String paramString()

Returns the parameter string representing the state of this text component. This string is useful for debugging.

Returns:: the parameter string of this text component.
Overrides:: paramString in class Component