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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
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 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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package javax.swing.text;

import java.io.*;
import java.text.*;
import java.util.*;
import javax.swing.*;

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:

Valid characters and their descriptions

  

    
Character
    
Description


  

    
#
    
Any valid number, uses Character.isDigit. 

    
'
    
Escape character, used to escape any of the special formatting
    characters.
  

    
U
    
Any character (Character.isLetter). All lowercase letters are mapped to upper case. 

    
L
    
Any character (Character.isLetter). All upper case letters are mapped to lower case. 

    
A
    
Any character or number (Character.isLetter or Character.isDigit). 

    
?
    
Any character (Character.isLetter). 

    
*
    
Anything.
  

    
H
    
Any 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:

  
If the inserted character is '-', it is accepted.
  
If the inserted character matches the mask for the next non-literal
      character, it is accepted at the new location.
  
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 JavaBeans™
has been added to the java.beans package. Please see XMLEncoder. 
Since:
1.4/**
 * <code>MaskFormatter</code> is used to format and edit strings. The behavior
 * of a <code>MaskFormatter</code> is controlled by way of a String mask
 * that specifies the valid characters that can be contained at a particular
 * location in the <code>Document</code> model. The following characters can
 * be specified:
 *
 * <table class="striped">
 * <caption>Valid characters and their descriptions</caption>
 * <thead>
 *   <tr>
 *     <th scope="col">Character
 *     <th scope="col">Description
 * </thead>
 * <tbody>
 *   <tr>
 *     <th scope="row">#
 *     <td>Any valid number, uses {@code Character.isDigit}.
 *   <tr>
 *     <th scope="row">'
 *     <td>Escape character, used to escape any of the special formatting
 *     characters.
 *   <tr>
 *     <th scope="row">U
 *     <td>Any character ({@code Character.isLetter}). All lowercase letters are
 *     mapped to upper case.
 *   <tr>
 *     <th scope="row">L
 *     <td>Any character ({@code Character.isLetter}). All upper case letters
 *     are mapped to lower case.
 *   <tr>
 *     <th scope="row">A
 *     <td>Any character or number ({@code Character.isLetter} or
 *     {@code Character.isDigit}).
 *   <tr>
 *     <th scope="row">?
 *     <td>Any character ({@code Character.isLetter}).
 *   <tr>
 *     <th scope="row">*
 *     <td>Anything.
 *   <tr>
 *     <th scope="row">H
 *     <td>Any hex character (0-9, a-f or A-F).
 * </tbody>
 * </table>
 *
 * <p>
 * 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.
 * <p>
 * You can further restrict the characters that can be input by the
 * <code>setInvalidCharacters</code> and <code>setValidCharacters</code>
 * methods. <code>setInvalidCharacters</code> allows you to specify
 * which characters are not legal. <code>setValidCharacters</code> 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:
 * <pre>
 * MaskFormatter formatter = new MaskFormatter("0x***");
 * formatter.setValidCharacters("0123456789abcdefABCDEF");
 * </pre>
 * <p>
 * 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:
 * <pre>
 *   MaskFormatter formatter = new MaskFormatter("###-####");
 *   formatter.setPlaceholderCharacter('_');
 *   formatter.getDisplayValue(tf, "123");
 * </pre>
 * <p>
 * Would result in the string '123-____'. If
 * <code>setPlaceholder("555-1212")</code> 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.
 * <p>
 * If a <code>MaskFormatter</code> is configured to only allow valid characters
 * (<code>setAllowsInvalid(false)</code>) literal characters will be skipped as
 * necessary when editing. Consider a <code>MaskFormatter</code> 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):
 * <pre>
 *   |555-1212
 *   5|55-1212
 *   55|5-1212
 *   555-|1212
 *   555-1|212
 * </pre>
 * The '-' is a literal (non-editable) character, and is skipped.
 * <p>
 * Similar behavior will result when editing. Consider inserting the string
 * '123-45' and '12345' into the <code>MaskFormatter</code> in the
 * previous example. Both inserts will result in the same String,
 * '123-45__'. When <code>MaskFormatter</code>
 * is processing the insert at character position 3 (the '-'), two things can
 * happen:
 * <ol>
 *   <li>If the inserted character is '-', it is accepted.
 *   <li>If the inserted character matches the mask for the next non-literal
 *       character, it is accepted at the new location.
 *   <li>Anything else results in an invalid edit
 * </ol>
 * <p>
 * By default <code>MaskFormatter</code> will not allow invalid edits, you can
 * change this with the <code>setAllowsInvalid</code> method, and will
 * commit edits on valid edits (use the <code>setCommitsOnValidEdit</code> to
 * change this).
 * <p>
 * By default, <code>MaskFormatter</code> 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 <code>setOverwriteMode</code>.
 * <p>
 * <strong>Warning:</strong>
 * 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&trade;
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @since 1.4
 */
@SuppressWarnings("serial") // Same-version serialization only
public class MaskFormatter extends DefaultFormatter {
    // Potential values in mask.
    private static final char DIGIT_KEY = '#';
    private static final char LITERAL_KEY = '\'';
    private static final char UPPERCASE_KEY = 'U';
    private static final char LOWERCASE_KEY = 'L';
    private static final char ALPHA_NUMERIC_KEY = 'A';
    private static final char CHARACTER_KEY = '?';
    private static final char ANYTHING_KEY = '*';
    private static final char HEX_KEY = 'H';

    private static final MaskCharacter[] EmptyMaskChars = new MaskCharacter[0];

    
The user specified mask. /** The user specified mask. */
    private String mask;

    private transient MaskCharacter[] maskChars;

    
List of valid characters. /** List of valid characters. */
    private String validCharacters;

    
List of invalid characters. /** List of invalid characters. */
    private String invalidCharacters;

    
String used for the passed in value if it does not completely
fill the mask. /** String used for the passed in value if it does not completely
     * fill the mask. */
    private String placeholderString;

    
String used to represent characters not present. /** String used to represent characters not present. */
    private char placeholder;

    
Indicates if the value contains the literal characters. /** Indicates if the value contains the literal characters. */
    private boolean containsLiteralChars;


    
Creates a MaskFormatter with no mask.
/**
     * Creates a MaskFormatter with no mask.
     */
    public MaskFormatter() {
        setAllowsInvalid(false);
        containsLiteralChars = true;
        maskChars = EmptyMaskChars;
        placeholder = ' ';
    }

    
Creates a MaskFormatter with the specified mask.
A ParseException
will be thrown if mask is an invalid mask.
Params:
mask – the mask
Throws:
ParseException – if mask does not contain valid mask characters/**
     * Creates a <code>MaskFormatter</code> with the specified mask.
     * A <code>ParseException</code>
     * will be thrown if <code>mask</code> is an invalid mask.
     * @param mask the mask
     * @throws ParseException if mask does not contain valid mask characters
     */
    public MaskFormatter(String mask) throws ParseException {
        this();
        setMask(mask);
    }

    
Sets the mask dictating the legal characters.
This will throw a ParseException if mask is
not valid.
Params:
mask – the mask
Throws:
ParseException – if mask does not contain valid mask characters/**
     * Sets the mask dictating the legal characters.
     * This will throw a <code>ParseException</code> if <code>mask</code> is
     * not valid.
     * @param mask the mask
     *
     * @throws ParseException if mask does not contain valid mask characters
     */
    public void setMask(String mask) throws ParseException {
        this.mask = mask;
        updateInternalMask();
    }

    
Returns the formatting mask.
Returns:
Mask dictating legal character values./**
     * Returns the formatting mask.
     *
     * @return Mask dictating legal character values.
     */
    public String getMask() {
        return mask;
    }

    
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.
Params:
validCharacters – If non-null, specifies legal characters./**
     * Allows for further restricting of the characters that can be input.
     * Only characters specified in the mask, not in the
     * <code>invalidCharacters</code>, and in
     * <code>validCharacters</code> 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.
     *
     * @param validCharacters If non-null, specifies legal characters.
     */
    public void setValidCharacters(String validCharacters) {
        this.validCharacters = validCharacters;
    }

    
Returns the valid characters that can be input.
Returns:
Legal characters/**
     * Returns the valid characters that can be input.
     *
     * @return Legal characters
     */
    public String getValidCharacters() {
        return 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 valid characters.
Params:
invalidCharacters – If non-null, specifies illegal characters./**
     * Allows for further restricting of the characters that can be input.
     * Only characters specified in the mask, not in the
     * <code>invalidCharacters</code>, and in
     * <code>validCharacters</code> 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.
     *
     * @param invalidCharacters If non-null, specifies illegal characters.
     */
    public void setInvalidCharacters(String invalidCharacters) {
        this.invalidCharacters = invalidCharacters;
    }

    
Returns the characters that are not valid for input.
Returns:
illegal characters./**
     * Returns the characters that are not valid for input.
     *
     * @return illegal characters.
     */
    public String getInvalidCharacters() {
        return invalidCharacters;
    }

    
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.
Params:
placeholder – String used when formatting if the value does not
       completely fill the mask/**
     * 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.
     *
     * @param placeholder String used when formatting if the value does not
     *        completely fill the mask
     */
    public void setPlaceholder(String placeholder) {
        this.placeholderString = placeholder;
    }

    
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/**
     * Returns the String to use if the value does not completely fill
     * in the mask.
     *
     * @return String used when formatting if the value does not
     *        completely fill the mask
     */
    public String getPlaceholder() {
        return placeholderString;
    }

    
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.
Params:
placeholder – Character used when formatting if the value does not
       completely fill the mask/**
     * 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.
     * <p>
     * This is only applicable if the placeholder string has not been
     * specified, or does not completely fill in the mask.
     *
     * @param placeholder Character used when formatting if the value does not
     *        completely fill the mask
     */
    public void setPlaceholderCharacter(char placeholder) {
        this.placeholder = placeholder;
    }

    
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/**
     * Returns the character to use in place of characters that are not present
     * in the value, ie the user must fill them in.
     *
     * @return Character used when formatting if the value does not
     *        completely fill the mask
     */
    public char getPlaceholderCharacter() {
        return placeholder;
    }

    
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'.
Params:
containsLiteralChars – Used to indicate if literal characters in
       mask should be returned in stringToValue/**
     * If true, the returned value and set value will also contain the literal
     * characters in mask.
     * <p>
     * For example, if the mask is <code>'(###) ###-####'</code>, the
     * current value is <code>'(415) 555-1212'</code>, and
     * <code>valueContainsLiteralCharacters</code> is
     * true <code>stringToValue</code> will return
     * <code>'(415) 555-1212'</code>. On the other hand, if
     * <code>valueContainsLiteralCharacters</code> is false,
     * <code>stringToValue</code> will return <code>'4155551212'</code>.
     *
     * @param containsLiteralChars Used to indicate if literal characters in
     *        mask should be returned in stringToValue
     */
    public void setValueContainsLiteralCharacters(
                        boolean containsLiteralChars) {
        this.containsLiteralChars = containsLiteralChars;
    }

    
Returns true if stringToValue should return literal
characters in the mask.
Returns:
True if literal characters in mask should be returned in
        stringToValue/**
     * Returns true if <code>stringToValue</code> should return literal
     * characters in the mask.
     *
     * @return True if literal characters in mask should be returned in
     *         stringToValue
     */
    public boolean getValueContainsLiteralCharacters() {
        return containsLiteralChars;
    }

    
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 for details on how literals are treated. 
Params:
value – String to convert
Throws:
ParseException – if there is an error in the conversion
See Also:
setValueContainsLiteralCharacters
Returns:
Object representation of text/**
     * Parses the text, returning the appropriate Object representation of
     * the String <code>value</code>. This strips the literal characters as
     * necessary and invokes supers <code>stringToValue</code>, so that if
     * you have specified a value class (<code>setValueClass</code>) an
     * instance of it will be created. This will throw a
     * <code>ParseException</code> if the value does not match the current
     * mask.  Refer to {@link #setValueContainsLiteralCharacters} for details
     * on how literals are treated.
     *
     * @throws ParseException if there is an error in the conversion
     * @param value String to convert
     * @see #setValueContainsLiteralCharacters
     * @return Object representation of text
     */
    public Object stringToValue(String value) throws ParseException {
        return stringToValue(value, true);
    }

    
Returns a String representation of the Object value based on the mask. Refer to setValueContainsLiteralCharacters for details on how literals are treated. 
Params:
value – Value to convert
Throws:
ParseException – if there is an error in the conversion
See Also:
setValueContainsLiteralCharacters
Returns:
String representation of value/**
     * Returns a String representation of the Object <code>value</code>
     * based on the mask.  Refer to
     * {@link #setValueContainsLiteralCharacters} for details
     * on how literals are treated.
     *
     * @throws ParseException if there is an error in the conversion
     * @param value Value to convert
     * @see #setValueContainsLiteralCharacters
     * @return String representation of value
     */
    public String valueToString(Object value) throws ParseException {
        String sValue = (value == null) ? "" : value.toString();
        StringBuilder result = new StringBuilder();
        String placeholder = getPlaceholder();
        int[] valueCounter = { 0 };

        append(result, sValue, valueCounter, placeholder, maskChars);
        return result.toString();
    }

    
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.
Params:
ftf – JFormattedTextField to format for, may be null indicating
           uninstall from current JFormattedTextField./**
     * Installs the <code>DefaultFormatter</code> onto a particular
     * <code>JFormattedTextField</code>.
     * This will invoke <code>valueToString</code> to convert the
     * current value from the <code>JFormattedTextField</code> to
     * a String. This will then install the <code>Action</code>s from
     * <code>getActions</code>, the <code>DocumentFilter</code>
     * returned from <code>getDocumentFilter</code> and the
     * <code>NavigationFilter</code> returned from
     * <code>getNavigationFilter</code> onto the
     * <code>JFormattedTextField</code>.
     * <p>
     * Subclasses will typically only need to override this if they
     * wish to install additional listeners on the
     * <code>JFormattedTextField</code>.
     * <p>
     * If there is a <code>ParseException</code> in converting the
     * current value to a String, this will set the text to an empty
     * String, and mark the <code>JFormattedTextField</code> as being
     * in an invalid state.
     * <p>
     * While this is a public method, this is typically only useful
     * for subclassers of <code>JFormattedTextField</code>.
     * <code>JFormattedTextField</code> will invoke this method at
     * the appropriate times when the value changes, or its internal
     * state changes.
     *
     * @param ftf JFormattedTextField to format for, may be null indicating
     *            uninstall from current JFormattedTextField.
     */
    public void install(JFormattedTextField ftf) {
        super.install(ftf);
        // valueToString doesn't throw, but stringToValue does, need to
        // update the editValid state appropriately
        if (ftf != null) {
            Object value = ftf.getValue();

            try {
                stringToValue(valueToString(value));
            } catch (ParseException pe) {
                setEditValid(false);
            }
        }
    }

    
Actual stringToValue implementation.
If completeMatch is true, the value must exactly match
the mask, on the other hand if completeMatch is false
the string must match the mask or the placeholder string.
/**
     * Actual <code>stringToValue</code> implementation.
     * If <code>completeMatch</code> is true, the value must exactly match
     * the mask, on the other hand if <code>completeMatch</code> is false
     * the string must match the mask or the placeholder string.
     */
    private Object stringToValue(String value, boolean completeMatch) throws
                         ParseException {
        int errorOffset;

        if ((errorOffset = getInvalidOffset(value, completeMatch)) == -1) {
            if (!getValueContainsLiteralCharacters()) {
                value = stripLiteralChars(value);
            }
            return super.stringToValue(value);
        }
        throw new ParseException("stringToValue passed invalid value",
                                 errorOffset);
    }

    
Returns -1 if the passed in string is valid, otherwise the index of
the first bogus character is returned.
/**
     * Returns -1 if the passed in string is valid, otherwise the index of
     * the first bogus character is returned.
     */
    private int getInvalidOffset(String string, boolean completeMatch) {
        int iLength = string.length();

        if (iLength != getMaxLength()) {
            // trivially false
            return iLength;
        }
        for (int counter = 0, max = string.length(); counter < max; counter++){
            char aChar = string.charAt(counter);

            if (!isValidCharacter(counter, aChar) &&
                (completeMatch || !isPlaceholder(counter, aChar))) {
                return counter;
            }
        }
        return -1;
    }

    
Invokes append on the mask characters in
mask.
/**
     * Invokes <code>append</code> on the mask characters in
     * <code>mask</code>.
     */
    private void append(StringBuilder result, String value, int[] index,
                        String placeholder, MaskCharacter[] mask)
                          throws ParseException {
        for (int counter = 0, maxCounter = mask.length;
             counter < maxCounter; counter++) {
            mask[counter].append(result, value, index, placeholder);
        }
    }

    
Updates the internal representation of the mask.
/**
     * Updates the internal representation of the mask.
     */
    private void updateInternalMask() throws ParseException {
        String mask = getMask();
        ArrayList<MaskCharacter> fixed = new ArrayList<MaskCharacter>();
        ArrayList<MaskCharacter> temp = fixed;

        if (mask != null) {
            for (int counter = 0, maxCounter = mask.length();
                 counter < maxCounter; counter++) {
                char maskChar = mask.charAt(counter);

                switch (maskChar) {
                case DIGIT_KEY:
                    temp.add(new DigitMaskCharacter());
                    break;
                case LITERAL_KEY:
                    if (++counter < maxCounter) {
                        maskChar = mask.charAt(counter);
                        temp.add(new LiteralCharacter(maskChar));
                    }
                    // else: Could actually throw if else
                    break;
                case UPPERCASE_KEY:
                    temp.add(new UpperCaseCharacter());
                    break;
                case LOWERCASE_KEY:
                    temp.add(new LowerCaseCharacter());
                    break;
                case ALPHA_NUMERIC_KEY:
                    temp.add(new AlphaNumericCharacter());
                    break;
                case CHARACTER_KEY:
                    temp.add(new CharCharacter());
                    break;
                case ANYTHING_KEY:
                    temp.add(new MaskCharacter());
                    break;
                case HEX_KEY:
                    temp.add(new HexCharacter());
                    break;
                default:
                    temp.add(new LiteralCharacter(maskChar));
                    break;
                }
            }
        }
        if (fixed.size() == 0) {
            maskChars = EmptyMaskChars;
        }
        else {
            maskChars = new MaskCharacter[fixed.size()];
            fixed.toArray(maskChars);
        }
    }

    
Returns the MaskCharacter at the specified location.
/**
     * Returns the MaskCharacter at the specified location.
     */
    private MaskCharacter getMaskCharacter(int index) {
        if (index >= maskChars.length) {
            return null;
        }
        return maskChars[index];
    }

    
Returns true if the placeholder character matches aChar.
/**
     * Returns true if the placeholder character matches aChar.
     */
    private boolean isPlaceholder(int index, char aChar) {
        return (getPlaceholderCharacter() == aChar);
    }

    
Returns true if the passed in character matches the mask at the
specified location.
/**
     * Returns true if the passed in character matches the mask at the
     * specified location.
     */
    private boolean isValidCharacter(int index, char aChar) {
        return getMaskCharacter(index).isValidCharacter(aChar);
    }

    
Returns true if the character at the specified location is a literal,
that is it can not be edited.
/**
     * Returns true if the character at the specified location is a literal,
     * that is it can not be edited.
     */
    private boolean isLiteral(int index) {
        return getMaskCharacter(index).isLiteral();
    }

    
Returns the maximum length the text can be.
/**
     * Returns the maximum length the text can be.
     */
    private int getMaxLength() {
        return maskChars.length;
    }

    
Returns the literal character at the specified location.
/**
     * Returns the literal character at the specified location.
     */
    private char getLiteral(int index) {
        return getMaskCharacter(index).getChar((char)0);
    }

    
Returns the character to insert at the specified location based on
the passed in character.  This provides a way to map certain sets
of characters to alternative values (lowercase to
uppercase...).
/**
     * Returns the character to insert at the specified location based on
     * the passed in character.  This provides a way to map certain sets
     * of characters to alternative values (lowercase to
     * uppercase...).
     */
    private char getCharacter(int index, char aChar) {
        return getMaskCharacter(index).getChar(aChar);
    }

    
Removes the literal characters from the passed in string.
/**
     * Removes the literal characters from the passed in string.
     */
    private String stripLiteralChars(String string) {
        StringBuilder sb = null;
        int last = 0;

        for (int counter = 0, max = string.length(); counter < max; counter++){
            if (isLiteral(counter)) {
                if (sb == null) {
                    sb = new StringBuilder();
                    if (counter > 0) {
                        sb.append(string.substring(0, counter));
                    }
                    last = counter + 1;
                }
                else if (last != counter) {
                    sb.append(string.substring(last, counter));
                }
                last = counter + 1;
            }
        }
        if (sb == null) {
            // Assume the mask isn't all literals.
            return string;
        }
        else if (last != string.length()) {
            if (sb == null) {
                return string.substring(last);
            }
            sb.append(string.substring(last));
        }
        return sb.toString();
    }


    
Subclassed to update the internal representation of the mask after
the default read operation has completed.
/**
     * Subclassed to update the internal representation of the mask after
     * the default read operation has completed.
     */
    private void readObject(ObjectInputStream s)
        throws IOException, ClassNotFoundException {
        ObjectInputStream.GetField f = s.readFields();

        validCharacters = (String) f.get("validCharacters", null);
        invalidCharacters = (String) f.get("invalidCharacters", null);
        placeholderString = (String) f.get("placeholderString", null);
        placeholder = f.get("placeholder", '\0');
        containsLiteralChars = f.get("containsLiteralChars", false);
        mask = (String) f.get("mask", null);

        try {
            updateInternalMask();
        } catch (ParseException pe) {
            // assert();
        }
    }

    
Returns true if the MaskFormatter allows invalid, or
the offset is less than the max length and the character at
offset is a literal.
/**
     * Returns true if the MaskFormatter allows invalid, or
     * the offset is less than the max length and the character at
     * <code>offset</code> is a literal.
     */
    boolean isNavigatable(int offset) {
        if (!getAllowsInvalid()) {
            return (offset < getMaxLength() && !isLiteral(offset));
        }
        return true;
    }

    /*
     * Returns true if the operation described by <code>rh</code> will
     * result in a legal edit.  This may set the <code>value</code>
     * field of <code>rh</code>.
     * <p>
     * This is overriden to return true for a partial match.
     */
    boolean isValidEdit(ReplaceHolder rh) {
        if (!getAllowsInvalid()) {
            String newString = getReplaceString(rh.offset, rh.length, rh.text);

            try {
                rh.value = stringToValue(newString, false);

                return true;
            } catch (ParseException pe) {
                return false;
            }
        }
        return true;
    }

    
This method does the following (assuming !getAllowsInvalid()):
iterate over the max of the deleted region or the text length, for
each character:

If it is valid (matches the mask at the particular position, or
    matches the literal character at the position), allow it
Else if the position identifies a literal character, add it. This
    allows for the user to paste in text that may/may not contain
    the literals.  For example, in pasing in 5551212 into ###-####
    when the 1 is evaluated it is illegal (by the first test), but there
    is a literal at this position (-), so it is used.  NOTE: This has
    a problem that you can't tell (without looking ahead) if you should
    eat literals in the text. For example, if you paste '555' into
    #5##, should it result in '5555' or '555 '? The current code will
    result in the latter, which feels a little better as selecting
    text than pasting will always result in the same thing.
Else if at the end of the inserted text, the replace the item with
    the placeholder
Otherwise the insert is bogus and false is returned.

/**
     * This method does the following (assuming !getAllowsInvalid()):
     * iterate over the max of the deleted region or the text length, for
     * each character:
     * <ol>
     * <li>If it is valid (matches the mask at the particular position, or
     *     matches the literal character at the position), allow it
     * <li>Else if the position identifies a literal character, add it. This
     *     allows for the user to paste in text that may/may not contain
     *     the literals.  For example, in pasing in 5551212 into ###-####
     *     when the 1 is evaluated it is illegal (by the first test), but there
     *     is a literal at this position (-), so it is used.  NOTE: This has
     *     a problem that you can't tell (without looking ahead) if you should
     *     eat literals in the text. For example, if you paste '555' into
     *     #5##, should it result in '5555' or '555 '? The current code will
     *     result in the latter, which feels a little better as selecting
     *     text than pasting will always result in the same thing.
     * <li>Else if at the end of the inserted text, the replace the item with
     *     the placeholder
     * <li>Otherwise the insert is bogus and false is returned.
     * </ol>
     */
    boolean canReplace(ReplaceHolder rh) {
        // This method is rather long, but much of the burden is in
        // maintaining a String and swapping to a StringBuilder only if
        // absolutely necessary.
        if (!getAllowsInvalid()) {
            StringBuilder replace = null;
            String text = rh.text;
            int tl = (text != null) ? text.length() : 0;

            if (tl == 0 && rh.length == 1 && getFormattedTextField().
                              getSelectionStart() != rh.offset) {
                // Backspace, adjust to actually delete next non-literal.
                while (rh.offset > 0 && isLiteral(rh.offset)) {
                    rh.offset--;
                }
            }
            int max = Math.min(getMaxLength() - rh.offset,
                               Math.max(tl, rh.length));
            for (int counter = 0, textIndex = 0; counter < max; counter++) {
                if (textIndex < tl && isValidCharacter(rh.offset + counter,
                                                   text.charAt(textIndex))) {
                    char aChar = text.charAt(textIndex);
                    if (aChar != getCharacter(rh.offset + counter, aChar)) {
                        if (replace == null) {
                            replace = new StringBuilder();
                            if (textIndex > 0) {
                                replace.append(text.substring(0, textIndex));
                            }
                        }
                    }
                    if (replace != null) {
                        replace.append(getCharacter(rh.offset + counter,
                                                    aChar));
                    }
                    textIndex++;
                }
                else if (isLiteral(rh.offset + counter)) {
                    if (replace != null) {
                        replace.append(getLiteral(rh.offset + counter));
                        if (textIndex < tl) {
                            max = Math.min(max + 1, getMaxLength() -
                                           rh.offset);
                        }
                    }
                    else if (textIndex > 0) {
                        replace = new StringBuilder(max);
                        replace.append(text.substring(0, textIndex));
                        replace.append(getLiteral(rh.offset + counter));
                        if (textIndex < tl) {
                            // Evaluate the character in text again.
                            max = Math.min(max + 1, getMaxLength() -
                                           rh.offset);
                        }
                        else if (rh.cursorPosition == -1) {
                            rh.cursorPosition = rh.offset + counter;
                        }
                    }
                    else {
                        rh.offset++;
                        rh.length--;
                        counter--;
                        max--;
                    }
                }
                else if (textIndex >= tl) {
                    // placeholder
                    if (replace == null) {
                        replace = new StringBuilder();
                        if (text != null) {
                            replace.append(text);
                        }
                    }
                    replace.append(getPlaceholderCharacter());
                    if (tl > 0 && rh.cursorPosition == -1) {
                        rh.cursorPosition = rh.offset + counter;
                    }
                }
                else {
                    // Bogus character.
                    return false;
                }
            }
            if (replace != null) {
                rh.text = replace.toString();
            }
            else if (text != null && rh.offset + tl > getMaxLength()) {
                rh.text = text.substring(0, getMaxLength() - rh.offset);
            }
            if (getOverwriteMode() && rh.text != null) {
                rh.length = rh.text.length();
            }
        }
        return super.canReplace(rh);
    }


    //
    // Interal classes used to represent the mask.
    //
    private class MaskCharacter {
        
Subclasses should override this returning true if the instance
represents a literal character. The default implementation
returns false.
/**
         * Subclasses should override this returning true if the instance
         * represents a literal character. The default implementation
         * returns false.
         */
        public boolean isLiteral() {
            return false;
        }

        
Returns true if aChar is a valid reprensentation of
the receiver. The default implementation returns true if the
receiver represents a literal character and getChar
== aChar. Otherwise, this will return true is aChar
is contained in the valid characters and not contained
in the invalid characters.
/**
         * Returns true if <code>aChar</code> is a valid reprensentation of
         * the receiver. The default implementation returns true if the
         * receiver represents a literal character and <code>getChar</code>
         * == aChar. Otherwise, this will return true is <code>aChar</code>
         * is contained in the valid characters and not contained
         * in the invalid characters.
         */
        public boolean isValidCharacter(char aChar) {
            if (isLiteral()) {
                return (getChar(aChar) == aChar);
            }

            aChar = getChar(aChar);

            String filter = getValidCharacters();

            if (filter != null && filter.indexOf(aChar) == -1) {
                return false;
            }
            filter = getInvalidCharacters();
            if (filter != null && filter.indexOf(aChar) != -1) {
                return false;
            }
            return true;
        }

        
Returns the character to insert for aChar. The
default implementation returns aChar. Subclasses
that wish to do some sort of mapping, perhaps lower case to upper
case should override this and do the necessary mapping.
/**
         * Returns the character to insert for <code>aChar</code>. The
         * default implementation returns <code>aChar</code>. Subclasses
         * that wish to do some sort of mapping, perhaps lower case to upper
         * case should override this and do the necessary mapping.
         */
        public char getChar(char aChar) {
            return aChar;
        }

        
Appends the necessary character in formatting at
index to buff.
/**
         * Appends the necessary character in <code>formatting</code> at
         * <code>index</code> to <code>buff</code>.
         */
        public void append(StringBuilder buff, String formatting, int[] index,
                           String placeholder)
                          throws ParseException {
            boolean inString = index[0] < formatting.length();
            char aChar = inString ? formatting.charAt(index[0]) : 0;

            if (isLiteral()) {
                buff.append(getChar(aChar));
                if (getValueContainsLiteralCharacters()) {
                    if (inString && aChar != getChar(aChar)) {
                        throw new ParseException("Invalid character: " +
                                                 aChar, index[0]);
                    }
                    index[0] = index[0] + 1;
                }
            }
            else if (index[0] >= formatting.length()) {
                if (placeholder != null && index[0] < placeholder.length()) {
                    buff.append(placeholder.charAt(index[0]));
                }
                else {
                    buff.append(getPlaceholderCharacter());
                }
                index[0] = index[0] + 1;
            }
            else if (isValidCharacter(aChar)) {
                buff.append(getChar(aChar));
                index[0] = index[0] + 1;
            }
            else {
                throw new ParseException("Invalid character: " + aChar,
                                         index[0]);
            }
        }
    }


    
Used to represent a fixed character in the mask.
/**
     * Used to represent a fixed character in the mask.
     */
    private class LiteralCharacter extends MaskCharacter {
        private char fixedChar;

        public LiteralCharacter(char fixedChar) {
            this.fixedChar = fixedChar;
        }

        public boolean isLiteral() {
            return true;
        }

        public char getChar(char aChar) {
            return fixedChar;
        }
    }


    
Represents a number, uses Character.isDigit.
/**
     * Represents a number, uses <code>Character.isDigit</code>.
     */
    private class DigitMaskCharacter extends MaskCharacter {
        public boolean isValidCharacter(char aChar) {
            return (Character.isDigit(aChar) &&
                    super.isValidCharacter(aChar));
        }
    }


    
Represents a character, lower case letters are mapped to upper case
using Character.toUpperCase.
/**
     * Represents a character, lower case letters are mapped to upper case
     * using <code>Character.toUpperCase</code>.
     */
    private class UpperCaseCharacter extends MaskCharacter {
        public boolean isValidCharacter(char aChar) {
            return (Character.isLetter(aChar) &&
                     super.isValidCharacter(aChar));
        }

        public char getChar(char aChar) {
            return Character.toUpperCase(aChar);
        }
    }


    
Represents a character, upper case letters are mapped to lower case
using Character.toLowerCase.
/**
     * Represents a character, upper case letters are mapped to lower case
     * using <code>Character.toLowerCase</code>.
     */
    private class LowerCaseCharacter extends MaskCharacter {
        public boolean isValidCharacter(char aChar) {
            return (Character.isLetter(aChar) &&
                     super.isValidCharacter(aChar));
        }

        public char getChar(char aChar) {
            return Character.toLowerCase(aChar);
        }
    }


    
Represents either a character or digit, uses
Character.isLetterOrDigit.
/**
     * Represents either a character or digit, uses
     * <code>Character.isLetterOrDigit</code>.
     */
    private class AlphaNumericCharacter extends MaskCharacter {
        public boolean isValidCharacter(char aChar) {
            return (Character.isLetterOrDigit(aChar) &&
                     super.isValidCharacter(aChar));
        }
    }


    
Represents a letter, uses Character.isLetter.
/**
     * Represents a letter, uses <code>Character.isLetter</code>.
     */
    private class CharCharacter extends MaskCharacter {
        public boolean isValidCharacter(char aChar) {
            return (Character.isLetter(aChar) &&
                     super.isValidCharacter(aChar));
        }
    }


    
Represents a hex character, 0-9a-fA-F. a-f is mapped to A-F
/**
     * Represents a hex character, 0-9a-fA-F. a-f is mapped to A-F
     */
    private class HexCharacter extends MaskCharacter {
        public boolean isValidCharacter(char aChar) {
            return ((aChar == '0' || aChar == '1' ||
                     aChar == '2' || aChar == '3' ||
                     aChar == '4' || aChar == '5' ||
                     aChar == '6' || aChar == '7' ||
                     aChar == '8' || aChar == '9' ||
                     aChar == 'a' || aChar == 'A' ||
                     aChar == 'b' || aChar == 'B' ||
                     aChar == 'c' || aChar == 'C' ||
                     aChar == 'd' || aChar == 'D' ||
                     aChar == 'e' || aChar == 'E' ||
                     aChar == 'f' || aChar == 'F') &&
                    super.isValidCharacter(aChar));
        }

        public char getChar(char aChar) {
            if (Character.isDigit(aChar)) {
                return aChar;
            }
            return Character.toUpperCase(aChar);
        }
    }
}