public class

MaskFormatter

extends DefaultFormatter
java.lang.Object
   ↳ javax.swing.JFormattedTextField.AbstractFormatter
     ↳ javax.swing.text.DefaultFormatter
       ↳ javax.swing.text.MaskFormatter

Class Overview

MaskFormatter is used to format and edit strings. The behavior of a MaskFormatter is controlled by way of a String mask that specifies the valid characters that can be contained at a particular location in the Document model. The following characters can be specified:

Character 

Description
# Any valid number, uses Character.isDigit.
' Escape character, used to escape any of the special formatting characters.
UAny character (Character.isLetter). All lowercase letters are mapped to upper case.
LAny character (Character.isLetter). All upper case letters are mapped to lower case.
AAny character or number (Character.isLetter or Character.isDigit)
?Any character (Character.isLetter).
*Anything.
HAny hex character (0-9, a-f or A-F).

Typically characters correspond to one char, but in certain languages this is not the case. The mask is on a per character basis, and will thus adjust to fit as many chars as are needed.

You can further restrict the characters that can be input by the setInvalidCharacters and setValidCharacters methods. setInvalidCharacters allows you to specify which characters are not legal. setValidCharacters allows you to specify which characters are valid. For example, the following code block is equivalent to a mask of '0xHHH' with no invalid/valid characters: 

 MaskFormatter formatter = new MaskFormatter("0x***");
 formatter.setValidCharacters("0123456789abcdefABCDEF");

When initially formatting a value if the length of the string is less than the length of the mask, two things can happen. Either the placeholder string will be used, or the placeholder character will be used. Precedence is given to the placeholder string. For example: 

   MaskFormatter formatter = new MaskFormatter("###-####");
   formatter.setPlaceholderCharacter('_');
   formatter.getDisplayValue(tf, "123");

Would result in the string '123-____'. If setPlaceholder("555-1212") was invoked '123-1212' would result. The placeholder String is only used on the initial format, on subsequent formats only the placeholder character will be used.

If a MaskFormatter is configured to only allow valid characters (setAllowsInvalid(false)) literal characters will be skipped as necessary when editing. Consider a MaskFormatter with the mask "###-####" and current value "555-1212". Using the right arrow key to navigate through the field will result in (| indicates the position of the caret): 

   |555-1212
   5|55-1212
   55|5-1212
   555-|1212
   555-1|212
The '-' is a literal (non-editable) character, and is skipped.

Similar behavior will result when editing. Consider inserting the string '123-45' and '12345' into the MaskFormatter in the previous example. Both inserts will result in the same String, '123-45__'. When MaskFormatter is processing the insert at character position 3 (the '-'), two things can happen:

  1. If the inserted character is '-', it is accepted.
  2. If the inserted character matches the mask for the next non-literal character, it is accepted at the new location.
  3. Anything else results in an invalid edit

By default MaskFormatter will not allow invalid edits, you can change this with the setAllowsInvalid method, and will commit edits on valid edits (use the setCommitsOnValidEdit to change this).

By default, MaskFormatter is in overwrite mode. That is as characters are typed a new character is not inserted, rather the character at the current location is replaced with the newly typed character. You can change this behavior by way of the method setOverwriteMode.

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 JavaBeansTM has been added to the java.beans package. Please see XMLEncoder.

Summary

Public Constructors
MaskFormatter()
Creates a MaskFormatter with no mask.
MaskFormatter(String mask)
Creates a MaskFormatter with the specified mask.
Public Methods
String getInvalidCharacters()
Returns the characters that are not valid for input.
String getMask()
Returns the formatting mask.
String getPlaceholder()
Returns the String to use if the value does not completely fill in the mask.
char getPlaceholderCharacter()
Returns the character to use in place of characters that are not present in the value, ie the user must fill them in.
String getValidCharacters()
Returns the valid characters that can be input.
boolean getValueContainsLiteralCharacters()
Returns true if stringToValue should return literal characters in the mask.
void install(JFormattedTextField ftf)
Installs the DefaultFormatter onto a particular JFormattedTextField.
void setInvalidCharacters(String invalidCharacters)
Allows for further restricting of the characters that can be input.
void setMask(String mask)
Sets the mask dictating the legal characters.
void setPlaceholder(String placeholder)
Sets the string to use if the value does not completely fill in the mask.
void setPlaceholderCharacter(char placeholder)
Sets the character to use in place of characters that are not present in the value, ie the user must fill them in.
void setValidCharacters(String validCharacters)
Allows for further restricting of the characters that can be input.
void setValueContainsLiteralCharacters(boolean containsLiteralChars)
If true, the returned value and set value will also contain the literal characters in mask.
Object stringToValue(String value)
Parses the text, returning the appropriate Object representation of the String value.
String valueToString(Object value)
Returns a String representation of the Object value based on the mask.
[Expand]
Inherited Methods
From class javax.swing.text.DefaultFormatter
From class javax.swing.JFormattedTextField.AbstractFormatter
From class java.lang.Object

Public Constructors

public MaskFormatter ()

Creates a MaskFormatter with no mask.

public MaskFormatter (String mask)

Creates a MaskFormatter with the specified mask. A ParseException will be thrown if mask is an invalid mask.

Throws
ParseException if mask does not contain valid mask characters

Public Methods

public String getInvalidCharacters ()

Returns the characters that are not valid for input.

Returns
  • illegal characters.

public String getMask ()

Returns the formatting mask.

Returns
  • Mask dictating legal character values.

public String getPlaceholder ()

Returns the String to use if the value does not completely fill in the mask.

Returns
  • String used when formatting if the value does not completely fill the mask

public char getPlaceholderCharacter ()

Returns the character to use in place of characters that are not present in the value, ie the user must fill them in.

Returns
  • Character used when formatting if the value does not completely fill the mask

public String getValidCharacters ()

Returns the valid characters that can be input.

Returns
  • Legal characters

public boolean getValueContainsLiteralCharacters ()

Returns true if stringToValue should return literal characters in the mask.

Returns
  • True if literal characters in mask should be returned in stringToValue

public void install (JFormattedTextField ftf)

Installs the DefaultFormatter onto a particular JFormattedTextField. This will invoke valueToString to convert the current value from the JFormattedTextField to a String. This will then install the Actions from getActions, the DocumentFilter returned from getDocumentFilter and the NavigationFilter returned from getNavigationFilter onto the JFormattedTextField.

Subclasses will typically only need to override this if they wish to install additional listeners on the JFormattedTextField.

If there is a ParseException in converting the current value to a String, this will set the text to an empty String, and mark the JFormattedTextField as being in an invalid state.

While this is a public method, this is typically only useful for subclassers of JFormattedTextField. JFormattedTextField will invoke this method at the appropriate times when the value changes, or its internal state changes.

Parameters
ftf JFormattedTextField to format for, may be null indicating uninstall from current JFormattedTextField.

public void setInvalidCharacters (String invalidCharacters)

Allows for further restricting of the characters that can be input. Only characters specified in the mask, not in the invalidCharacters, and in validCharacters will be allowed to be input. Passing in null (the default) implies the valid characters are only bound by the mask and the valid characters.

Parameters
invalidCharacters If non-null, specifies illegal characters.

public void setMask (String mask)

Sets the mask dictating the legal characters. This will throw a ParseException if mask is not valid.

Throws
ParseException if mask does not contain valid mask characters

public void setPlaceholder (String placeholder)

Sets the string to use if the value does not completely fill in the mask. A null value implies the placeholder char should be used.

Parameters
placeholder String used when formatting if the value does not completely fill the mask

public void setPlaceholderCharacter (char placeholder)

Sets the character to use in place of characters that are not present in the value, ie the user must fill them in. The default value is a space.

This is only applicable if the placeholder string has not been specified, or does not completely fill in the mask.

Parameters
placeholder Character used when formatting if the value does not completely fill the mask

public void setValidCharacters (String validCharacters)

Allows for further restricting of the characters that can be input. Only characters specified in the mask, not in the invalidCharacters, and in validCharacters will be allowed to be input. Passing in null (the default) implies the valid characters are only bound by the mask and the invalid characters.

Parameters
validCharacters If non-null, specifies legal characters.

public void setValueContainsLiteralCharacters (boolean containsLiteralChars)

If true, the returned value and set value will also contain the literal characters in mask.

For example, if the mask is '(###) ###-####', the current value is '(415) 555-1212', and valueContainsLiteralCharacters is true stringToValue will return '(415) 555-1212'. On the other hand, if valueContainsLiteralCharacters is false, stringToValue will return '4155551212'.

Parameters
containsLiteralChars Used to indicate if literal characters in mask should be returned in stringToValue

public Object stringToValue (String value)

Parses the text, returning the appropriate Object representation of the String value. This strips the literal characters as necessary and invokes supers stringToValue, so that if you have specified a value class (setValueClass) an instance of it will be created. This will throw a ParseException if the value does not match the current mask. Refer to setValueContainsLiteralCharacters(boolean) for details on how literals are treated.

Parameters
value String to convert
Returns
  • Object representation of text
Throws
ParseException if there is an error in the conversion
See Also

public String valueToString (Object value)

Returns a String representation of the Object value based on the mask. Refer to setValueContainsLiteralCharacters(boolean) for details on how literals are treated.

Parameters
value Value to convert
Returns
  • String representation of value
Throws
ParseException if there is an error in the conversion
See Also