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Class com.sun.java.swing.JTextField

java.lang.Object
   |
   +----java.awt.Component
           |
           +----java.awt.Container
                   |
                   +----com.sun.java.swing.JComponent
                           |
                           +----com.sun.java.swing.text.JTextComponent
                                   |
                                   +----com.sun.java.swing.JTextField

public class JTextField

extends JTextComponent

implements SwingConstants

JTextField has a method to establish the string used as the command string for the action event that gets fired. The java.awt.TextField used the text of the field as the command string for the ActionEvent. JTextField will use the command string set with the setActionCommand method if not null, otherwise it will use the text of the field as a compatibility with java.awt.TextField.

The method setEchoChar and getEchoChar are not provided directly to avoid a new implementation of a pluggable look-and-feel inadvertantly exposing password characters. To provide password-like services a seperate class JPasswordField extends JTextField to provide this service with an independantly pluggable look-and-feel.

The java.awt.TextField could be monitored for changes by adding a TextListener for TextEvent's. In the JTextComponent based components, changes are broadcasted from the model via a DocumentEvent to DocumentListeners. The DocumentEvent gives the location of the change and the kind of change if desired. The code fragment might look something like:

    DocumentListener myListener = ??;
    JTextField myArea = ??;
    myArea.getDocument().addDocumentListener(myListener);
 

The horizontal alignment of JTextField can be set to be left justified, centered, or right justified if the required size of the field text is smaller than the size allocated to it. This is determined by the setHorizontalAlignment and getHorizontalAlignment methods. The default is to be left justified.

For the keyboard keys used by this component in the standard Look and Feel (L&F) renditions, see the JTextField key assignments.

Customized fields can easily be created by extending the model and changing the default model provided. For example, the following piece of code will create a field that holds only upper case characters. It will work even if text is pasted into from the clipboard or it is altered via programmatic changes.

public class UpperCaseField extends JTextField {
public UpperCaseField(int cols) {
super(cols);
}
protected Document createDefaultModel() {
return new UpperCaseDocument();
}
static class UpperCaseDocument extends PlainDocument {
public void insertString(int offs, String str, AttributeSet a) 
throws BadLocationException {
if (str == null) {
return;
}
char[] upper = str.toCharArray();
for (int i = 0; i < upper.length; i++) {
upper[i] = Character.toUpperCase(upper[i]);
}
super.insertString(offs, new String(upper), a);
}
}
}
 

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:

setActionCommand, JPasswordField

notifyAction

Name of the action to send notification that the contents of the field have been accepted.

JTextField()

Constructs a new TextField.

JTextField(Document, String, int)

Constructs a new JTextField that uses the given text storage model and the given number of columns.

JTextField(int)

Constructs a new empty TextField with the specified number of columns.

JTextField(String)

Constructs a new TextField initialized with the specified text.

JTextField(String, int)

Constructs a new TextField initialized with the specified text and columns.

addActionListener(ActionListener)

Adds the specified action listener to receive action events from this textfield.

createDefaultModel()

Creates the default implementation of the model to be used at construction if one isn't explicitly given.

fireActionPerformed()

Notifies all listeners that have registered interest for notification on this event type.

getAccessibleContext()

Get the AccessibleContext associated with this JTextField.

getActions()

Fetches the command list for the editor.

getColumns()

Returns the number of columns in this TextField.

getColumnWidth()

Gets the column width.

getHorizontalAlignment()

Returns the horizontal alignment of the text.

getHorizontalVisibility()

Gets the visibility of the text field.

getMinimumSize()

Returns the minimum size Dimensions needed for this TextField.

getPreferredSize()

Returns the preferred size Dimensions needed for this TextField.

getScrollOffset()

Gets the scroll offset.

getUIClassID()

Gets the class ID for a UI.

isValidateRoot()

Calls to revalidate that come from within the textfield itself will be handled by validating the textfield.

paramString()

Returns the String of parameters for this JTextField (columns + command string).

postActionEvent()

Processes action events occurring on this textfield by dispatching them to any registered ActionListener objects.

removeActionListener(ActionListener)

Removes the specified action listener so that it no longer receives action events from this textfield.

scrollRectToVisible(Rectangle)

Scrolls the field left or right.

setActionCommand(String)

Sets the command string used for action events.

setColumns(int)

Sets the number of columns in this TextField, and then invalidate the layout.

setFont(Font)

Sets the current font.

setHorizontalAlignment(int)

Sets the horizontal alignment of the text.

setScrollOffset(int)

Sets the scroll offset.

 public static final String notifyAction

Name of the action to send notification that the contents of the field have been accepted. Typically this is bound to a carriage-return.

 public JTextField()

Constructs a new TextField. A default model is created, the initial string is null, and the number of columns is set to 0.

 public JTextField(String text)

Constructs a new TextField initialized with the specified text. A default model is created and the number of columns is 0.

Parameters:

text - the text to be displayed, or null

 public JTextField(int columns)

Constructs a new empty TextField with the specified number of columns. A default model is created and the initial string is set to null.

Parameters:

columns - the number of columns to use to calculate the preferred width. If columns is set to zero, the preferred width will be whatever naturally results from the component implementation.

 public JTextField(String text,
                   int columns)

Constructs a new TextField initialized with the specified text and columns. A default model is created.

Parameters:

text - the text to be displayed, or null

columns - the number of columns to use to calculate the preferred width. If columns is set to zero, the preferred width will be whatever naturally results from the component implementation.

 public JTextField(Document doc,
                   String text,
                   int columns)

Constructs a new JTextField that uses the given text storage model and the given number of columns. This is the constructor through which the other constructors feed. If the document is null, a default model is created.

Parameters:

doc - the text storage to use. If this is null, a default will be provided by calling the createDefaultModel method.

text - the initial string to display, or null

columns - the number of columns to use to calculate the preferred width >= 0. If columns is set to zero, the preferred width will be whatever naturally results from the component implementation.

Throws: IllegalArgumentException

if columns < 0

 public String getUIClassID()

Gets the class ID for a UI.

Returns:

the ID ("TextFieldUI")

Overrides:

getUIClassID in class JComponent

See Also:

getUIClassID, getUI

 public boolean isValidateRoot()

Calls to revalidate that come from within the textfield itself will be handled by validating the textfield.

Overrides:

isValidateRoot in class JComponent

See Also:

revalidate, isValidateRoot

 public int getHorizontalAlignment()

Returns the horizontal alignment of the text. Valid keys: JTextField.LEFT (the default), JTextField.CENTER, JTextField.RIGHT.

Returns:

the alignment

 public void setHorizontalAlignment(int alignment)

Sets the horizontal alignment of the text. Valid keys: JTextField.LEFT (the default), JTextField.CENTER, JTextField.RIGHT. invalidate() and repaint() are called when the alignment is set, and a PropertyChange event ("horizontalAlignment") is fired.

Parameters:

alignment - the alignment

Throws: IllegalArgumentException

if the alignment specified is not a valid key.

 protected Document createDefaultModel()

Creates the default implementation of the model to be used at construction if one isn't explicitly given. An instance of PlainDocument is returned.

Returns:

the default model implementation

 public int getColumns()

Returns the number of columns in this TextField.

Returns:

the number of columns >= 0

 public void setColumns(int columns)

Sets the number of columns in this TextField, and then invalidate the layout.

Parameters:

columns - the number of columns >= 0

Throws: IllegalArgumentException

if columns is less than 0

 protected int getColumnWidth()

Gets the column width. The meaning of what a column is can be considered a fairly weak notion for some fonts. This method is used to define the width of a column. By default this is defined to be the width of the character m for the font used. This method can be redefined to be some alternative amount

Returns:

the column width >= 1

 public Dimension getPreferredSize()

Returns the preferred size Dimensions needed for this TextField. If a non-zero number of columns has been set, the width is set to the columns multiplied by the column width.

Returns:

the dimensions

Overrides:

getPreferredSize in class JComponent

 public Dimension getMinimumSize()

Returns the minimum size Dimensions needed for this TextField. This defaults to the preferred size.

Returns:

the dimensions

Overrides:

getMinimumSize in class JComponent

 public void setFont(Font f)

Sets the current font. This removes cached row height and column width so the new font will be reflected. revalidate() is called after setting the font.

Parameters:

f - the new font

Overrides:

setFont in class Component

 public synchronized void addActionListener(ActionListener l)

Adds the specified action listener to receive action events from this textfield.

Parameters:

l - the action listener

 public synchronized void removeActionListener(ActionListener l)

Removes the specified action listener so that it no longer receives action events from this textfield.

Parameters:

l - the action listener

 protected void fireActionPerformed()

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. The listener list is processed in last to first order.

See Also:

EventListenerList

 public void setActionCommand(String command)

Sets the command string used for action events.

Parameters:

command - the command string

 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

Overrides:

getActions in class JTextComponent

 public void postActionEvent()

Processes action events occurring on this textfield by dispatching them to any registered ActionListener objects. This is normally called by the controller registered with textfield.

 protected String paramString()

Returns the String of parameters for this JTextField (columns + command string).

Returns:

the string of parameters

Overrides:

paramString in class Container

 public BoundedRangeModel getHorizontalVisibility()

Gets the visibility of the text field. This can be adjusted to change the location of the visible area if the size of the field is greater than the area that was allocated to the field. The fields look-and-feel implementation manages the values of the minimum, maximum, and extent properties on the BoundedRangeModel.

Returns:

the visibility

See Also:

BoundedRangeModel

 public int getScrollOffset()

Gets the scroll offset.

Returns:

the offset >= 0

 public void setScrollOffset(int scrollOffset)

Sets the scroll offset.

Parameters:

scrollOffset - the offset >= 0

 public void scrollRectToVisible(Rectangle r)

Scrolls the field left or right.

Parameters:

r - the region to scroll

Overrides:

scrollRectToVisible in class JComponent

 public AccessibleContext getAccessibleContext()

Get the AccessibleContext associated with this JTextField. Creates a new context if necessary.

Returns:

the AccessibleContext of this JTextField

Overrides:

getAccessibleContext in class JTextComponent

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