Class JPasswordField

public class JPasswordField
extends JTextField

JPasswordField is a lightweight component that allows the editing of a single line of text where the view indicates something was typed, but does not show the original characters. You can find further information and examples in How to Use Text Fields, a section in The Java Tutorial.

JPasswordField is intended to be source-compatible with java.awt.TextField used with echoChar set. It is provided separately to make it easier to safely change the UI for the JTextField without affecting password entries.

NOTE: By default, JPasswordField disables input methods; otherwise, input characters could be visible while they were composed using input methods. If an application needs the input methods support, please use the inherited method, enableInputMethods(true).

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

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 applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans™ has been added to the java.beans package. Please see XMLEncoder.

Constructors

JPasswordField

public JPasswordField()

Constructs a new JPasswordField, with a default document, null starting text string, and 0 column width.

JPasswordField

public JPasswordField(String text)

Constructs a new JPasswordField initialized with the specified text. The document model is set to the default, and the number of columns to 0.

Parameters:

text - the text to be displayed, null if none

JPasswordField

public JPasswordField(int columns)

Constructs a new empty JPasswordField 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 >= 0

JPasswordField

public JPasswordField(String text,
                      int columns)

Constructs a new JPasswordField initialized with the specified text and columns. The document model is set to the default.

Parameters:

text - the text to be displayed, null if none

columns - the number of columns >= 0

JPasswordField

public JPasswordField(Document doc,
                      String txt,
                      int columns)

Constructs a new JPasswordField that uses the given text storage model and the given number of columns. This is the constructor through which the other constructors feed. The echo character is set to '*', but may be changed by the current Look and Feel. If the document model is null, a default one will be created.

Parameters:

doc - the text storage to use

txt - the text to be displayed, null if none

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

Methods

getUIClassID

public String getUIClassID()

Returns the name of the L&F class that renders this component.

Overrides:

getUIClassID in class JTextField

Returns:

the string "PasswordFieldUI"

See Also:

JComponent.getUIClassID(), UIDefaults.getUI(javax.swing.JComponent)

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. invalidate is called after setting the UI.

Overrides:

updateUI in class JTextComponent

Since:

1.6

See Also:

JComponent.setUI(javax.swing.plaf.ComponentUI), UIManager.getLookAndFeel(), UIManager.getUI(javax.swing.JComponent)

getEchoChar

public char getEchoChar()

Returns the character to be used for echoing. The default is '*'. The default may be different depending on the currently running Look and Feel. For example, Metal/Ocean's default is a bullet character.

Returns:

the echo character, 0 if unset

See Also:

setEchoChar(char), echoCharIsSet()

setEchoChar

public void setEchoChar(char c)

Sets the echo character for this JPasswordField. Note that this is largely a suggestion, since the view that gets installed can use whatever graphic techniques it desires to represent the field. Setting a value of 0 indicates that you wish to see the text as it is typed, similar to the behavior of a standard JTextField.

Parameters:

c - the echo character to display

See Also:

echoCharIsSet(), getEchoChar()

echoCharIsSet

public boolean echoCharIsSet()

Returns true if this JPasswordField has a character set for echoing. A character is considered to be set if the echo character is not 0.

Returns:

true if a character is set for echoing

See Also:

setEchoChar(char), getEchoChar()

cut

public void cut()

Invokes provideErrorFeedback on the current look and feel, which typically initiates an error beep. The normal behavior of transferring the currently selected range in the associated text model to the system clipboard, and removing the contents from the model, is not acceptable for a password field.

Overrides:

cut in class JTextComponent

See Also:

Toolkit.getSystemClipboard(), Clipboard

copy

public void copy()

Invokes provideErrorFeedback on the current look and feel, which typically initiates an error beep. The normal behavior of transferring the currently selected range in the associated text model to the system clipboard, and leaving the contents from the model, is not acceptable for a password field.

Overrides:

copy in class JTextComponent

See Also:

Toolkit.getSystemClipboard(), Clipboard

getText

@Deprecated
public String getText()

Deprecated. As of Java 2 platform v1.2, replaced by getPassword.

Overrides:

getText in class JTextComponent

Returns:

the text

See Also:

JTextComponent.setText(java.lang.String)

getText

@Deprecated
public String getText(int offs,
                                  int len)
                           throws BadLocationException

Deprecated. As of Java 2 platform v1.2, replaced by getPassword.

Overrides:

getText in class JTextComponent

Parameters:

offs - the offset >= 0

len - the length >= 0

Returns:

the text

Throws:

BadLocationException - if the offset or length are invalid

getPassword

public char[] getPassword()

Returns the text contained in this TextComponent. If the underlying document is null, will give a NullPointerException. For stronger security, it is recommended that the returned character array be cleared after use by setting each character to zero.

Returns:

the text

paramString

protected String paramString()

Returns a string representation of this JPasswordField. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null.

Overrides:

paramString in class JTextField

Returns:

a string representation of this JPasswordField

getAccessibleContext

public AccessibleContext getAccessibleContext()

Returns the AccessibleContext associated with this JPasswordField. For password fields, the AccessibleContext takes the form of an AccessibleJPasswordField. A new AccessibleJPasswordField instance is created if necessary.

Specified by:

getAccessibleContext in interface Accessible

Overrides:

getAccessibleContext in class JTextField

Returns:

an AccessibleJPasswordField that serves as the AccessibleContext of this JPasswordField