1 /*
   2  * Copyright (c) 1996, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 /*
  27  * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
  28  * (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved
  29  *
  30  *   The original version of this source code and documentation is copyrighted
  31  * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
  32  * materials are provided under terms of a License Agreement between Taligent
  33  * and Sun. This technology is protected by multiple US and International
  34  * patents. This notice and attribution to Taligent may not be removed.
  35  *   Taligent is a registered trademark of Taligent, Inc.
  36  *
  37  */
  38 
  39 package java.text;
  40 
  41 import java.io.InvalidObjectException;
  42 import java.io.IOException;
  43 import java.io.ObjectInputStream;
  44 import java.io.ObjectOutputStream;
  45 import java.math.BigInteger;
  46 import java.math.RoundingMode;
  47 import java.text.spi.NumberFormatProvider;
  48 import java.util.Currency;
  49 import java.util.HashMap;
  50 import java.util.Hashtable;
  51 import java.util.Locale;
  52 import java.util.Map;
  53 import java.util.ResourceBundle;
  54 import java.util.concurrent.atomic.AtomicInteger;
  55 import java.util.concurrent.atomic.AtomicLong;
  56 import java.util.spi.LocaleServiceProvider;
  57 import sun.util.locale.provider.LocaleProviderAdapter;
  58 import sun.util.locale.provider.LocaleServiceProviderPool;
  59 
  60 /**
  61  * <code>NumberFormat</code> is the abstract base class for all number
  62  * formats. This class provides the interface for formatting and parsing
  63  * numbers. <code>NumberFormat</code> also provides methods for determining
  64  * which locales have number formats, and what their names are.
  65  *
  66  * <p>
  67  * <code>NumberFormat</code> helps you to format and parse numbers for any locale.
  68  * Your code can be completely independent of the locale conventions for
  69  * decimal points, thousands-separators, or even the particular decimal
  70  * digits used, or whether the number format is even decimal.
  71  *
  72  * <p>
  73  * To format a number for the current Locale, use one of the factory
  74  * class methods:
  75  * <blockquote>
  76  * <pre>{@code
  77  * myString = NumberFormat.getInstance().format(myNumber);
  78  * }</pre>
  79  * </blockquote>
  80  * If you are formatting multiple numbers, it is
  81  * more efficient to get the format and use it multiple times so that
  82  * the system doesn't have to fetch the information about the local
  83  * language and country conventions multiple times.
  84  * <blockquote>
  85  * <pre>{@code
  86  * NumberFormat nf = NumberFormat.getInstance();
  87  * for (int i = 0; i < myNumber.length; ++i) {
  88  *     output.println(nf.format(myNumber[i]) + "; ");
  89  * }
  90  * }</pre>
  91  * </blockquote>
  92  * To format a number for a different Locale, specify it in the
  93  * call to <code>getInstance</code>.
  94  * <blockquote>
  95  * <pre>{@code
  96  * NumberFormat nf = NumberFormat.getInstance(Locale.FRENCH);
  97  * }</pre>
  98  * </blockquote>
  99  *
 100  * <p>If the locale contains "nu" (numbers) and/or "rg" (region override)
 101  * <a href="../util/Locale.html#def_locale_extension">Unicode extensions</a>,
 102  * the decimal digits, and/or the country used for formatting are overridden.
 103  * If both "nu" and "rg" are specified, the decimal digits from the "nu"
 104  * extension supersedes the implicit one from the "rg" extension.
 105  *
 106  * <p>You can also use a {@code NumberFormat} to parse numbers:
 107  * <blockquote>
 108  * <pre>{@code
 109  * myNumber = nf.parse(myString);
 110  * }</pre>
 111  * </blockquote>
 112  * Use <code>getInstance</code> or <code>getNumberInstance</code> to get the
 113  * normal number format. Use <code>getIntegerInstance</code> to get an
 114  * integer number format. Use <code>getCurrencyInstance</code> to get the
 115  * currency number format. And use <code>getPercentInstance</code> to get a
 116  * format for displaying percentages. With this format, a fraction like
 117  * 0.53 is displayed as 53%.
 118  *
 119  * <p>
 120  * You can also control the display of numbers with such methods as
 121  * <code>setMinimumFractionDigits</code>.
 122  * If you want even more control over the format or parsing,
 123  * or want to give your users more control,
 124  * you can try casting the <code>NumberFormat</code> you get from the factory methods
 125  * to a <code>DecimalFormat</code>. This will work for the vast majority
 126  * of locales; just remember to put it in a <code>try</code> block in case you
 127  * encounter an unusual one.
 128  *
 129  * <p>
 130  * NumberFormat and DecimalFormat are designed such that some controls
 131  * work for formatting and others work for parsing.  The following is
 132  * the detailed description for each these control methods,
 133  * <p>
 134  * setParseIntegerOnly : only affects parsing, e.g.
 135  * if true,  "3456.78" &rarr; 3456 (and leaves the parse position just after index 6)
 136  * if false, "3456.78" &rarr; 3456.78 (and leaves the parse position just after index 8)
 137  * This is independent of formatting.  If you want to not show a decimal point
 138  * where there might be no digits after the decimal point, use
 139  * setDecimalSeparatorAlwaysShown.
 140  * <p>
 141  * setDecimalSeparatorAlwaysShown : only affects formatting, and only where
 142  * there might be no digits after the decimal point, such as with a pattern
 143  * like "#,##0.##", e.g.,
 144  * if true,  3456.00 &rarr; "3,456."
 145  * if false, 3456.00 &rarr; "3456"
 146  * This is independent of parsing.  If you want parsing to stop at the decimal
 147  * point, use setParseIntegerOnly.
 148  *
 149  * <p>
 150  * You can also use forms of the <code>parse</code> and <code>format</code>
 151  * methods with <code>ParsePosition</code> and <code>FieldPosition</code> to
 152  * allow you to:
 153  * <ul>
 154  * <li> progressively parse through pieces of a string
 155  * <li> align the decimal point and other areas
 156  * </ul>
 157  * For example, you can align numbers in two ways:
 158  * <ol>
 159  * <li> If you are using a monospaced font with spacing for alignment,
 160  *      you can pass the <code>FieldPosition</code> in your format call, with
 161  *      <code>field</code> = <code>INTEGER_FIELD</code>. On output,
 162  *      <code>getEndIndex</code> will be set to the offset between the
 163  *      last character of the integer and the decimal. Add
 164  *      (desiredSpaceCount - getEndIndex) spaces at the front of the string.
 165  *
 166  * <li> If you are using proportional fonts,
 167  *      instead of padding with spaces, measure the width
 168  *      of the string in pixels from the start to <code>getEndIndex</code>.
 169  *      Then move the pen by
 170  *      (desiredPixelWidth - widthToAlignmentPoint) before drawing the text.
 171  *      It also works where there is no decimal, but possibly additional
 172  *      characters at the end, e.g., with parentheses in negative
 173  *      numbers: "(12)" for -12.
 174  * </ol>
 175  *
 176  * <h3><a id="synchronization">Synchronization</a></h3>
 177  *
 178  * <p>
 179  * Number formats are generally not synchronized.
 180  * It is recommended to create separate format instances for each thread.
 181  * If multiple threads access a format concurrently, it must be synchronized
 182  * externally.
 183  *
 184  * @implSpec The {@link #format(double, StringBuffer, FieldPosition)},
 185  * {@link #format(long, StringBuffer, FieldPosition)} and
 186  * {@link #parse(String, ParsePosition)} methods may throw
 187  * {@code NullPointerException}, if any of their parameter is {@code null}.
 188  * The subclass may provide its own implementation and specification about
 189  * {@code NullPointerException}.
 190  *
 191  * <p>
 192  * The default implementation provides rounding modes defined
 193  * in {@link java.math.RoundingMode} for formatting numbers. It
 194  * uses the {@linkplain java.math.RoundingMode#HALF_EVEN
 195  * round half-even algorithm}. To change the rounding mode use
 196  * {@link #setRoundingMode(java.math.RoundingMode) setRoundingMode}.
 197  * The {@code NumberFormat} returned by the static factory methods is
 198  * configured to round floating point numbers using half-even
 199  * rounding (see {@link java.math.RoundingMode#HALF_EVEN
 200  * RoundingMode.HALF_EVEN}) for formatting.
 201  *
 202  * @see          DecimalFormat
 203  * @see          ChoiceFormat
 204  * @author       Mark Davis
 205  * @author       Helena Shih
 206  * @since 1.1
 207  */
 208 public abstract class NumberFormat extends Format  {
 209 
 210     /**
 211      * Field constant used to construct a FieldPosition object. Signifies that
 212      * the position of the integer part of a formatted number should be returned.
 213      * @see java.text.FieldPosition
 214      */
 215     public static final int INTEGER_FIELD = 0;
 216 
 217     /**
 218      * Field constant used to construct a FieldPosition object. Signifies that
 219      * the position of the fraction part of a formatted number should be returned.
 220      * @see java.text.FieldPosition
 221      */
 222     public static final int FRACTION_FIELD = 1;
 223 
 224     /**
 225      * Sole constructor.  (For invocation by subclass constructors, typically
 226      * implicit.)
 227      */
 228     protected NumberFormat() {
 229     }
 230 
 231     /**
 232      * Formats a number and appends the resulting text to the given string
 233      * buffer.
 234      * The number can be of any subclass of {@link java.lang.Number}.
 235      * <p>
 236      * This implementation extracts the number's value using
 237      * {@link java.lang.Number#longValue()} for all integral type values that
 238      * can be converted to <code>long</code> without loss of information,
 239      * including <code>BigInteger</code> values with a
 240      * {@link java.math.BigInteger#bitLength() bit length} of less than 64,
 241      * and {@link java.lang.Number#doubleValue()} for all other types. It
 242      * then calls
 243      * {@link #format(long,java.lang.StringBuffer,java.text.FieldPosition)}
 244      * or {@link #format(double,java.lang.StringBuffer,java.text.FieldPosition)}.
 245      * This may result in loss of magnitude information and precision for
 246      * <code>BigInteger</code> and <code>BigDecimal</code> values.
 247      * @param number     the number to format
 248      * @param toAppendTo the <code>StringBuffer</code> to which the formatted
 249      *                   text is to be appended
 250      * @param pos        keeps track on the position of the field within the
 251      *                   returned string. For example, for formatting a number
 252      *                   {@code 1234567.89} in {@code Locale.US} locale,
 253      *                   if the given {@code fieldPosition} is
 254      *                   {@link NumberFormat#INTEGER_FIELD}, the begin index
 255      *                   and end index of {@code fieldPosition} will be set
 256      *                   to 0 and 9, respectively for the output string
 257      *                   {@code 1,234,567.89}.
 258      * @return           the value passed in as <code>toAppendTo</code>
 259      * @exception        IllegalArgumentException if <code>number</code> is
 260      *                   null or not an instance of <code>Number</code>.
 261      * @exception        NullPointerException if <code>toAppendTo</code> or
 262      *                   <code>pos</code> is null
 263      * @exception        ArithmeticException if rounding is needed with rounding
 264      *                   mode being set to RoundingMode.UNNECESSARY
 265      * @see              java.text.FieldPosition
 266      */
 267     @Override
 268     public StringBuffer format(Object number,
 269                                StringBuffer toAppendTo,
 270                                FieldPosition pos) {
 271         if (number instanceof Long || number instanceof Integer ||
 272             number instanceof Short || number instanceof Byte ||
 273             number instanceof AtomicInteger || number instanceof AtomicLong ||
 274             (number instanceof BigInteger &&
 275              ((BigInteger)number).bitLength() < 64)) {
 276             return format(((Number)number).longValue(), toAppendTo, pos);
 277         } else if (number instanceof Number) {
 278             return format(((Number)number).doubleValue(), toAppendTo, pos);
 279         } else {
 280             throw new IllegalArgumentException("Cannot format given Object as a Number");
 281         }
 282     }
 283 
 284     /**
 285      * Parses text from a string to produce a <code>Number</code>.
 286      * <p>
 287      * The method attempts to parse text starting at the index given by
 288      * <code>pos</code>.
 289      * If parsing succeeds, then the index of <code>pos</code> is updated
 290      * to the index after the last character used (parsing does not necessarily
 291      * use all characters up to the end of the string), and the parsed
 292      * number is returned. The updated <code>pos</code> can be used to
 293      * indicate the starting point for the next call to this method.
 294      * If an error occurs, then the index of <code>pos</code> is not
 295      * changed, the error index of <code>pos</code> is set to the index of
 296      * the character where the error occurred, and null is returned.
 297      * <p>
 298      * See the {@link #parse(String, ParsePosition)} method for more information
 299      * on number parsing.
 300      *
 301      * @param source A <code>String</code>, part of which should be parsed.
 302      * @param pos A <code>ParsePosition</code> object with index and error
 303      *            index information as described above.
 304      * @return A <code>Number</code> parsed from the string. In case of
 305      *         error, returns null.
 306      * @throws NullPointerException if {@code source} or {@code pos} is null.
 307      */
 308     @Override
 309     public final Object parseObject(String source, ParsePosition pos) {
 310         return parse(source, pos);
 311     }
 312 
 313    /**
 314      * Specialization of format.
 315      *
 316      * @param number the double number to format
 317      * @return the formatted String
 318      * @exception        ArithmeticException if rounding is needed with rounding
 319      *                   mode being set to RoundingMode.UNNECESSARY
 320      * @see java.text.Format#format
 321      */
 322     public final String format(double number) {
 323         // Use fast-path for double result if that works
 324         String result = fastFormat(number);
 325         if (result != null)
 326             return result;
 327 
 328         return format(number, new StringBuffer(),
 329                       DontCareFieldPosition.INSTANCE).toString();
 330     }
 331 
 332     /*
 333      * fastFormat() is supposed to be implemented in concrete subclasses only.
 334      * Default implem always returns null.
 335      */
 336     String fastFormat(double number) { return null; }
 337 
 338    /**
 339      * Specialization of format.
 340      *
 341      * @param number the long number to format
 342      * @return the formatted String
 343      * @exception        ArithmeticException if rounding is needed with rounding
 344      *                   mode being set to RoundingMode.UNNECESSARY
 345      * @see java.text.Format#format
 346      */
 347     public final String format(long number) {
 348         return format(number, new StringBuffer(),
 349                       DontCareFieldPosition.INSTANCE).toString();
 350     }
 351 
 352    /**
 353      * Specialization of format.
 354      *
 355      * @param number     the double number to format
 356      * @param toAppendTo the StringBuffer to which the formatted text is to be
 357      *                   appended
 358      * @param pos        keeps track on the position of the field within the
 359      *                   returned string. For example, for formatting a number
 360      *                   {@code 1234567.89} in {@code Locale.US} locale,
 361      *                   if the given {@code fieldPosition} is
 362      *                   {@link NumberFormat#INTEGER_FIELD}, the begin index
 363      *                   and end index of {@code fieldPosition} will be set
 364      *                   to 0 and 9, respectively for the output string
 365      *                   {@code 1,234,567.89}.
 366      * @return the formatted StringBuffer
 367      * @exception        ArithmeticException if rounding is needed with rounding
 368      *                   mode being set to RoundingMode.UNNECESSARY
 369      * @see java.text.Format#format
 370      */
 371     public abstract StringBuffer format(double number,
 372                                         StringBuffer toAppendTo,
 373                                         FieldPosition pos);
 374 
 375    /**
 376      * Specialization of format.
 377      *
 378      * @param number     the long number to format
 379      * @param toAppendTo the StringBuffer to which the formatted text is to be
 380      *                   appended
 381      * @param pos        keeps track on the position of the field within the
 382      *                   returned string. For example, for formatting a number
 383      *                   {@code 123456789} in {@code Locale.US} locale,
 384      *                   if the given {@code fieldPosition} is
 385      *                   {@link NumberFormat#INTEGER_FIELD}, the begin index
 386      *                   and end index of {@code fieldPosition} will be set
 387      *                   to 0 and 11, respectively for the output string
 388      *                   {@code 123,456,789}.
 389      * @return the formatted StringBuffer
 390      * @exception        ArithmeticException if rounding is needed with rounding
 391      *                   mode being set to RoundingMode.UNNECESSARY
 392      * @see java.text.Format#format
 393      */
 394     public abstract StringBuffer format(long number,
 395                                         StringBuffer toAppendTo,
 396                                         FieldPosition pos);
 397 
 398    /**
 399      * Returns a Long if possible (e.g., within the range [Long.MIN_VALUE,
 400      * Long.MAX_VALUE] and with no decimals), otherwise a Double.
 401      * If IntegerOnly is set, will stop at a decimal
 402      * point (or equivalent; e.g., for rational numbers "1 2/3", will stop
 403      * after the 1).
 404      * Does not throw an exception; if no object can be parsed, index is
 405      * unchanged!
 406      *
 407      * @param source the String to parse
 408      * @param parsePosition the parse position
 409      * @return the parsed value
 410      * @see java.text.NumberFormat#isParseIntegerOnly
 411      * @see java.text.Format#parseObject
 412      */
 413     public abstract Number parse(String source, ParsePosition parsePosition);
 414 
 415     /**
 416      * Parses text from the beginning of the given string to produce a number.
 417      * The method may not use the entire text of the given string.
 418      * <p>
 419      * See the {@link #parse(String, ParsePosition)} method for more information
 420      * on number parsing.
 421      *
 422      * @param source A <code>String</code> whose beginning should be parsed.
 423      * @return A <code>Number</code> parsed from the string.
 424      * @exception ParseException if the beginning of the specified string
 425      *            cannot be parsed.
 426      */
 427     public Number parse(String source) throws ParseException {
 428         ParsePosition parsePosition = new ParsePosition(0);
 429         Number result = parse(source, parsePosition);
 430         if (parsePosition.index == 0) {
 431             throw new ParseException("Unparseable number: \"" + source + "\"",
 432                                      parsePosition.errorIndex);
 433         }
 434         return result;
 435     }
 436 
 437     /**
 438      * Returns true if this format will parse numbers as integers only.
 439      * For example in the English locale, with ParseIntegerOnly true, the
 440      * string "1234." would be parsed as the integer value 1234 and parsing
 441      * would stop at the "." character.  Of course, the exact format accepted
 442      * by the parse operation is locale dependent and determined by sub-classes
 443      * of NumberFormat.
 444      *
 445      * @return {@code true} if numbers should be parsed as integers only;
 446      *         {@code false} otherwise
 447      */
 448     public boolean isParseIntegerOnly() {
 449         return parseIntegerOnly;
 450     }
 451 
 452     /**
 453      * Sets whether or not numbers should be parsed as integers only.
 454      *
 455      * @param value {@code true} if numbers should be parsed as integers only;
 456      *              {@code false} otherwise
 457      * @see #isParseIntegerOnly
 458      */
 459     public void setParseIntegerOnly(boolean value) {
 460         parseIntegerOnly = value;
 461     }
 462 
 463     //============== Locale Stuff =====================
 464 
 465     /**
 466      * Returns a general-purpose number format for the current default
 467      * {@link java.util.Locale.Category#FORMAT FORMAT} locale.
 468      * This is the same as calling
 469      * {@link #getNumberInstance() getNumberInstance()}.
 470      *
 471      * @return the {@code NumberFormat} instance for general-purpose number
 472      * formatting
 473      */
 474     public static final NumberFormat getInstance() {
 475         return getInstance(Locale.getDefault(Locale.Category.FORMAT), NUMBERSTYLE);
 476     }
 477 
 478     /**
 479      * Returns a general-purpose number format for the specified locale.
 480      * This is the same as calling
 481      * {@link #getNumberInstance(java.util.Locale) getNumberInstance(inLocale)}.
 482      *
 483      * @param inLocale the desired locale
 484      * @return the {@code NumberFormat} instance for general-purpose number
 485      * formatting
 486      */
 487     public static NumberFormat getInstance(Locale inLocale) {
 488         return getInstance(inLocale, NUMBERSTYLE);
 489     }
 490 
 491     /**
 492      * Returns a general-purpose number format for the current default
 493      * {@link java.util.Locale.Category#FORMAT FORMAT} locale.
 494      * <p>This is equivalent to calling
 495      * {@link #getNumberInstance(Locale)
 496      *     getNumberInstance(Locale.getDefault(Locale.Category.FORMAT))}.
 497      *
 498      * @return the {@code NumberFormat} instance for general-purpose number
 499      * formatting
 500      * @see java.util.Locale#getDefault(java.util.Locale.Category)
 501      * @see java.util.Locale.Category#FORMAT
 502      */
 503     public static final NumberFormat getNumberInstance() {
 504         return getInstance(Locale.getDefault(Locale.Category.FORMAT), NUMBERSTYLE);
 505     }
 506 
 507     /**
 508      * Returns a general-purpose number format for the specified locale.
 509      *
 510      * @param inLocale the desired locale
 511      * @return the {@code NumberFormat} instance for general-purpose number
 512      * formatting
 513      */
 514     public static NumberFormat getNumberInstance(Locale inLocale) {
 515         return getInstance(inLocale, NUMBERSTYLE);
 516     }
 517 
 518     /**
 519      * Returns an integer number format for the current default
 520      * {@link java.util.Locale.Category#FORMAT FORMAT} locale. The
 521      * returned number format is configured to round floating point numbers
 522      * to the nearest integer using half-even rounding (see {@link
 523      * java.math.RoundingMode#HALF_EVEN RoundingMode.HALF_EVEN}) for formatting,
 524      * and to parse only the integer part of an input string (see {@link
 525      * #isParseIntegerOnly isParseIntegerOnly}).
 526      * <p>This is equivalent to calling
 527      * {@link #getIntegerInstance(Locale)
 528      *     getIntegerInstance(Locale.getDefault(Locale.Category.FORMAT))}.
 529      *
 530      * @see #getRoundingMode()
 531      * @see java.util.Locale#getDefault(java.util.Locale.Category)
 532      * @see java.util.Locale.Category#FORMAT
 533      * @return a number format for integer values
 534      * @since 1.4
 535      */
 536     public static final NumberFormat getIntegerInstance() {
 537         return getInstance(Locale.getDefault(Locale.Category.FORMAT), INTEGERSTYLE);
 538     }
 539 
 540     /**
 541      * Returns an integer number format for the specified locale. The
 542      * returned number format is configured to round floating point numbers
 543      * to the nearest integer using half-even rounding (see {@link
 544      * java.math.RoundingMode#HALF_EVEN RoundingMode.HALF_EVEN}) for formatting,
 545      * and to parse only the integer part of an input string (see {@link
 546      * #isParseIntegerOnly isParseIntegerOnly}).
 547      *
 548      * @param inLocale the desired locale
 549      * @see #getRoundingMode()
 550      * @return a number format for integer values
 551      * @since 1.4
 552      */
 553     public static NumberFormat getIntegerInstance(Locale inLocale) {
 554         return getInstance(inLocale, INTEGERSTYLE);
 555     }
 556 
 557     /**
 558      * Returns a currency format for the current default
 559      * {@link java.util.Locale.Category#FORMAT FORMAT} locale.
 560      * <p>This is equivalent to calling
 561      * {@link #getCurrencyInstance(Locale)
 562      *     getCurrencyInstance(Locale.getDefault(Locale.Category.FORMAT))}.
 563      *
 564      * @return the {@code NumberFormat} instance for currency formatting
 565      * @see java.util.Locale#getDefault(java.util.Locale.Category)
 566      * @see java.util.Locale.Category#FORMAT
 567      */
 568     public static final NumberFormat getCurrencyInstance() {
 569         return getInstance(Locale.getDefault(Locale.Category.FORMAT), CURRENCYSTYLE);
 570     }
 571 
 572     /**
 573      * Returns a currency format for the specified locale.
 574      *
 575      * @param inLocale the desired locale
 576      * @return the {@code NumberFormat} instance for currency formatting
 577      */
 578     public static NumberFormat getCurrencyInstance(Locale inLocale) {
 579         return getInstance(inLocale, CURRENCYSTYLE);
 580     }
 581 
 582     /**
 583      * Returns a percentage format for the current default
 584      * {@link java.util.Locale.Category#FORMAT FORMAT} locale.
 585      * <p>This is equivalent to calling
 586      * {@link #getPercentInstance(Locale)
 587      *     getPercentInstance(Locale.getDefault(Locale.Category.FORMAT))}.
 588      *
 589      * @return the {@code NumberFormat} instance for percentage formatting
 590      * @see java.util.Locale#getDefault(java.util.Locale.Category)
 591      * @see java.util.Locale.Category#FORMAT
 592      */
 593     public static final NumberFormat getPercentInstance() {
 594         return getInstance(Locale.getDefault(Locale.Category.FORMAT), PERCENTSTYLE);
 595     }
 596 
 597     /**
 598      * Returns a percentage format for the specified locale.
 599      *
 600      * @param inLocale the desired locale
 601      * @return the {@code NumberFormat} instance for percentage formatting
 602      */
 603     public static NumberFormat getPercentInstance(Locale inLocale) {
 604         return getInstance(inLocale, PERCENTSTYLE);
 605     }
 606 
 607     /**
 608      * Returns a scientific format for the current default locale.
 609      */
 610     /*public*/ final static NumberFormat getScientificInstance() {
 611         return getInstance(Locale.getDefault(Locale.Category.FORMAT), SCIENTIFICSTYLE);
 612     }
 613 
 614     /**
 615      * Returns a scientific format for the specified locale.
 616      *
 617      * @param inLocale the desired locale
 618      */
 619     /*public*/ static NumberFormat getScientificInstance(Locale inLocale) {
 620         return getInstance(inLocale, SCIENTIFICSTYLE);
 621     }
 622 
 623     /**
 624      * Returns an array of all locales for which the
 625      * <code>get*Instance</code> methods of this class can return
 626      * localized instances.
 627      * The returned array represents the union of locales supported by the Java
 628      * runtime and by installed
 629      * {@link java.text.spi.NumberFormatProvider NumberFormatProvider} implementations.
 630      * It must contain at least a <code>Locale</code> instance equal to
 631      * {@link java.util.Locale#US Locale.US}.
 632      *
 633      * @return An array of locales for which localized
 634      *         <code>NumberFormat</code> instances are available.
 635      */
 636     public static Locale[] getAvailableLocales() {
 637         LocaleServiceProviderPool pool =
 638             LocaleServiceProviderPool.getPool(NumberFormatProvider.class);
 639         return pool.getAvailableLocales();
 640     }
 641 
 642     /**
 643      * Overrides hashCode.
 644      */
 645     @Override
 646     public int hashCode() {
 647         return maximumIntegerDigits * 37 + maxFractionDigits;
 648         // just enough fields for a reasonable distribution
 649     }
 650 
 651     /**
 652      * Overrides equals.
 653      */
 654     @Override
 655     public boolean equals(Object obj) {
 656         if (obj == null) {
 657             return false;
 658         }
 659         if (this == obj) {
 660             return true;
 661         }
 662         if (getClass() != obj.getClass()) {
 663             return false;
 664         }
 665         NumberFormat other = (NumberFormat) obj;
 666         return (maximumIntegerDigits == other.maximumIntegerDigits
 667             && minimumIntegerDigits == other.minimumIntegerDigits
 668             && maximumFractionDigits == other.maximumFractionDigits
 669             && minimumFractionDigits == other.minimumFractionDigits
 670             && groupingUsed == other.groupingUsed
 671             && parseIntegerOnly == other.parseIntegerOnly);
 672     }
 673 
 674     /**
 675      * Overrides Cloneable.
 676      */
 677     @Override
 678     public Object clone() {
 679         NumberFormat other = (NumberFormat) super.clone();
 680         return other;
 681     }
 682 
 683     /**
 684      * Returns true if grouping is used in this format. For example, in the
 685      * English locale, with grouping on, the number 1234567 might be formatted
 686      * as "1,234,567". The grouping separator as well as the size of each group
 687      * is locale dependent and is determined by sub-classes of NumberFormat.
 688      *
 689      * @return {@code true} if grouping is used;
 690      *         {@code false} otherwise
 691      * @see #setGroupingUsed
 692      */
 693     public boolean isGroupingUsed() {
 694         return groupingUsed;
 695     }
 696 
 697     /**
 698      * Set whether or not grouping will be used in this format.
 699      *
 700      * @param newValue {@code true} if grouping is used;
 701      *                 {@code false} otherwise
 702      * @see #isGroupingUsed
 703      */
 704     public void setGroupingUsed(boolean newValue) {
 705         groupingUsed = newValue;
 706     }
 707 
 708     /**
 709      * Returns the maximum number of digits allowed in the integer portion of a
 710      * number.
 711      *
 712      * @return the maximum number of digits
 713      * @see #setMaximumIntegerDigits
 714      */
 715     public int getMaximumIntegerDigits() {
 716         return maximumIntegerDigits;
 717     }
 718 
 719     /**
 720      * Sets the maximum number of digits allowed in the integer portion of a
 721      * number. maximumIntegerDigits must be &ge; minimumIntegerDigits.  If the
 722      * new value for maximumIntegerDigits is less than the current value
 723      * of minimumIntegerDigits, then minimumIntegerDigits will also be set to
 724      * the new value.
 725      *
 726      * @param newValue the maximum number of integer digits to be shown; if
 727      * less than zero, then zero is used. The concrete subclass may enforce an
 728      * upper limit to this value appropriate to the numeric type being formatted.
 729      * @see #getMaximumIntegerDigits
 730      */
 731     public void setMaximumIntegerDigits(int newValue) {
 732         maximumIntegerDigits = Math.max(0,newValue);
 733         if (minimumIntegerDigits > maximumIntegerDigits) {
 734             minimumIntegerDigits = maximumIntegerDigits;
 735         }
 736     }
 737 
 738     /**
 739      * Returns the minimum number of digits allowed in the integer portion of a
 740      * number.
 741      *
 742      * @return the minimum number of digits
 743      * @see #setMinimumIntegerDigits
 744      */
 745     public int getMinimumIntegerDigits() {
 746         return minimumIntegerDigits;
 747     }
 748 
 749     /**
 750      * Sets the minimum number of digits allowed in the integer portion of a
 751      * number. minimumIntegerDigits must be &le; maximumIntegerDigits.  If the
 752      * new value for minimumIntegerDigits exceeds the current value
 753      * of maximumIntegerDigits, then maximumIntegerDigits will also be set to
 754      * the new value
 755      *
 756      * @param newValue the minimum number of integer digits to be shown; if
 757      * less than zero, then zero is used. The concrete subclass may enforce an
 758      * upper limit to this value appropriate to the numeric type being formatted.
 759      * @see #getMinimumIntegerDigits
 760      */
 761     public void setMinimumIntegerDigits(int newValue) {
 762         minimumIntegerDigits = Math.max(0,newValue);
 763         if (minimumIntegerDigits > maximumIntegerDigits) {
 764             maximumIntegerDigits = minimumIntegerDigits;
 765         }
 766     }
 767 
 768     /**
 769      * Returns the maximum number of digits allowed in the fraction portion of a
 770      * number.
 771      *
 772      * @return the maximum number of digits.
 773      * @see #setMaximumFractionDigits
 774      */
 775     public int getMaximumFractionDigits() {
 776         return maximumFractionDigits;
 777     }
 778 
 779     /**
 780      * Sets the maximum number of digits allowed in the fraction portion of a
 781      * number. maximumFractionDigits must be &ge; minimumFractionDigits.  If the
 782      * new value for maximumFractionDigits is less than the current value
 783      * of minimumFractionDigits, then minimumFractionDigits will also be set to
 784      * the new value.
 785      *
 786      * @param newValue the maximum number of fraction digits to be shown; if
 787      * less than zero, then zero is used. The concrete subclass may enforce an
 788      * upper limit to this value appropriate to the numeric type being formatted.
 789      * @see #getMaximumFractionDigits
 790      */
 791     public void setMaximumFractionDigits(int newValue) {
 792         maximumFractionDigits = Math.max(0,newValue);
 793         if (maximumFractionDigits < minimumFractionDigits) {
 794             minimumFractionDigits = maximumFractionDigits;
 795         }
 796     }
 797 
 798     /**
 799      * Returns the minimum number of digits allowed in the fraction portion of a
 800      * number.
 801      *
 802      * @return the minimum number of digits
 803      * @see #setMinimumFractionDigits
 804      */
 805     public int getMinimumFractionDigits() {
 806         return minimumFractionDigits;
 807     }
 808 
 809     /**
 810      * Sets the minimum number of digits allowed in the fraction portion of a
 811      * number. minimumFractionDigits must be &le; maximumFractionDigits.  If the
 812      * new value for minimumFractionDigits exceeds the current value
 813      * of maximumFractionDigits, then maximumIntegerDigits will also be set to
 814      * the new value
 815      *
 816      * @param newValue the minimum number of fraction digits to be shown; if
 817      * less than zero, then zero is used. The concrete subclass may enforce an
 818      * upper limit to this value appropriate to the numeric type being formatted.
 819      * @see #getMinimumFractionDigits
 820      */
 821     public void setMinimumFractionDigits(int newValue) {
 822         minimumFractionDigits = Math.max(0,newValue);
 823         if (maximumFractionDigits < minimumFractionDigits) {
 824             maximumFractionDigits = minimumFractionDigits;
 825         }
 826     }
 827 
 828     /**
 829      * Gets the currency used by this number format when formatting
 830      * currency values. The initial value is derived in a locale dependent
 831      * way. The returned value may be null if no valid
 832      * currency could be determined and no currency has been set using
 833      * {@link #setCurrency(java.util.Currency) setCurrency}.
 834      * <p>
 835      * The default implementation throws
 836      * <code>UnsupportedOperationException</code>.
 837      *
 838      * @return the currency used by this number format, or <code>null</code>
 839      * @exception UnsupportedOperationException if the number format class
 840      * doesn't implement currency formatting
 841      * @since 1.4
 842      */
 843     public Currency getCurrency() {
 844         throw new UnsupportedOperationException();
 845     }
 846 
 847     /**
 848      * Sets the currency used by this number format when formatting
 849      * currency values. This does not update the minimum or maximum
 850      * number of fraction digits used by the number format.
 851      * <p>
 852      * The default implementation throws
 853      * <code>UnsupportedOperationException</code>.
 854      *
 855      * @param currency the new currency to be used by this number format
 856      * @exception UnsupportedOperationException if the number format class
 857      * doesn't implement currency formatting
 858      * @exception NullPointerException if <code>currency</code> is null
 859      * @since 1.4
 860      */
 861     public void setCurrency(Currency currency) {
 862         throw new UnsupportedOperationException();
 863     }
 864 
 865     /**
 866      * Gets the {@link java.math.RoundingMode} used in this NumberFormat.
 867      * The default implementation of this method in NumberFormat
 868      * always throws {@link java.lang.UnsupportedOperationException}.
 869      * Subclasses which handle different rounding modes should override
 870      * this method.
 871      *
 872      * @exception UnsupportedOperationException The default implementation
 873      *     always throws this exception
 874      * @return The <code>RoundingMode</code> used for this NumberFormat.
 875      * @see #setRoundingMode(RoundingMode)
 876      * @since 1.6
 877      */
 878     public RoundingMode getRoundingMode() {
 879         throw new UnsupportedOperationException();
 880     }
 881 
 882     /**
 883      * Sets the {@link java.math.RoundingMode} used in this NumberFormat.
 884      * The default implementation of this method in NumberFormat always
 885      * throws {@link java.lang.UnsupportedOperationException}.
 886      * Subclasses which handle different rounding modes should override
 887      * this method.
 888      *
 889      * @exception UnsupportedOperationException The default implementation
 890      *     always throws this exception
 891      * @exception NullPointerException if <code>roundingMode</code> is null
 892      * @param roundingMode The <code>RoundingMode</code> to be used
 893      * @see #getRoundingMode()
 894      * @since 1.6
 895      */
 896     public void setRoundingMode(RoundingMode roundingMode) {
 897         throw new UnsupportedOperationException();
 898     }
 899 
 900     // =======================privates===============================
 901 
 902     private static NumberFormat getInstance(Locale desiredLocale,
 903                                            int choice) {
 904         LocaleProviderAdapter adapter;
 905         adapter = LocaleProviderAdapter.getAdapter(NumberFormatProvider.class,
 906                                                    desiredLocale);
 907         NumberFormat numberFormat = getInstance(adapter, desiredLocale, choice);
 908         if (numberFormat == null) {
 909             numberFormat = getInstance(LocaleProviderAdapter.forJRE(),
 910                                        desiredLocale, choice);
 911         }
 912         return numberFormat;
 913     }
 914 
 915     private static NumberFormat getInstance(LocaleProviderAdapter adapter,
 916                                             Locale locale, int choice) {
 917         NumberFormatProvider provider = adapter.getNumberFormatProvider();
 918         NumberFormat numberFormat = null;
 919         switch (choice) {
 920         case NUMBERSTYLE:
 921             numberFormat = provider.getNumberInstance(locale);
 922             break;
 923         case PERCENTSTYLE:
 924             numberFormat = provider.getPercentInstance(locale);
 925             break;
 926         case CURRENCYSTYLE:
 927             numberFormat = provider.getCurrencyInstance(locale);
 928             break;
 929         case INTEGERSTYLE:
 930             numberFormat = provider.getIntegerInstance(locale);
 931             break;
 932         }
 933         return numberFormat;
 934     }
 935 
 936     /**
 937      * First, read in the default serializable data.
 938      *
 939      * Then, if <code>serialVersionOnStream</code> is less than 1, indicating that
 940      * the stream was written by JDK 1.1,
 941      * set the <code>int</code> fields such as <code>maximumIntegerDigits</code>
 942      * to be equal to the <code>byte</code> fields such as <code>maxIntegerDigits</code>,
 943      * since the <code>int</code> fields were not present in JDK 1.1.
 944      * Finally, set serialVersionOnStream back to the maximum allowed value so that
 945      * default serialization will work properly if this object is streamed out again.
 946      *
 947      * <p>If <code>minimumIntegerDigits</code> is greater than
 948      * <code>maximumIntegerDigits</code> or <code>minimumFractionDigits</code>
 949      * is greater than <code>maximumFractionDigits</code>, then the stream data
 950      * is invalid and this method throws an <code>InvalidObjectException</code>.
 951      * In addition, if any of these values is negative, then this method throws
 952      * an <code>InvalidObjectException</code>.
 953      *
 954      * @since 1.2
 955      */
 956     private void readObject(ObjectInputStream stream)
 957          throws IOException, ClassNotFoundException
 958     {
 959         stream.defaultReadObject();
 960         if (serialVersionOnStream < 1) {
 961             // Didn't have additional int fields, reassign to use them.
 962             maximumIntegerDigits = maxIntegerDigits;
 963             minimumIntegerDigits = minIntegerDigits;
 964             maximumFractionDigits = maxFractionDigits;
 965             minimumFractionDigits = minFractionDigits;
 966         }
 967         if (minimumIntegerDigits > maximumIntegerDigits ||
 968             minimumFractionDigits > maximumFractionDigits ||
 969             minimumIntegerDigits < 0 || minimumFractionDigits < 0) {
 970             throw new InvalidObjectException("Digit count range invalid");
 971         }
 972         serialVersionOnStream = currentSerialVersion;
 973     }
 974 
 975     /**
 976      * Write out the default serializable data, after first setting
 977      * the <code>byte</code> fields such as <code>maxIntegerDigits</code> to be
 978      * equal to the <code>int</code> fields such as <code>maximumIntegerDigits</code>
 979      * (or to <code>Byte.MAX_VALUE</code>, whichever is smaller), for compatibility
 980      * with the JDK 1.1 version of the stream format.
 981      *
 982      * @since 1.2
 983      */
 984     private void writeObject(ObjectOutputStream stream)
 985          throws IOException
 986     {
 987         maxIntegerDigits = (maximumIntegerDigits > Byte.MAX_VALUE) ?
 988                            Byte.MAX_VALUE : (byte)maximumIntegerDigits;
 989         minIntegerDigits = (minimumIntegerDigits > Byte.MAX_VALUE) ?
 990                            Byte.MAX_VALUE : (byte)minimumIntegerDigits;
 991         maxFractionDigits = (maximumFractionDigits > Byte.MAX_VALUE) ?
 992                             Byte.MAX_VALUE : (byte)maximumFractionDigits;
 993         minFractionDigits = (minimumFractionDigits > Byte.MAX_VALUE) ?
 994                             Byte.MAX_VALUE : (byte)minimumFractionDigits;
 995         stream.defaultWriteObject();
 996     }
 997 
 998     // Constants used by factory methods to specify a style of format.
 999     private static final int NUMBERSTYLE = 0;
1000     private static final int CURRENCYSTYLE = 1;
1001     private static final int PERCENTSTYLE = 2;
1002     private static final int SCIENTIFICSTYLE = 3;
1003     private static final int INTEGERSTYLE = 4;
1004 
1005     /**
1006      * True if the grouping (i.e. thousands) separator is used when
1007      * formatting and parsing numbers.
1008      *
1009      * @serial
1010      * @see #isGroupingUsed
1011      */
1012     private boolean groupingUsed = true;
1013 
1014     /**
1015      * The maximum number of digits allowed in the integer portion of a
1016      * number.  <code>maxIntegerDigits</code> must be greater than or equal to
1017      * <code>minIntegerDigits</code>.
1018      * <p>
1019      * <strong>Note:</strong> This field exists only for serialization
1020      * compatibility with JDK 1.1.  In Java platform 2 v1.2 and higher, the new
1021      * <code>int</code> field <code>maximumIntegerDigits</code> is used instead.
1022      * When writing to a stream, <code>maxIntegerDigits</code> is set to
1023      * <code>maximumIntegerDigits</code> or <code>Byte.MAX_VALUE</code>,
1024      * whichever is smaller.  When reading from a stream, this field is used
1025      * only if <code>serialVersionOnStream</code> is less than 1.
1026      *
1027      * @serial
1028      * @see #getMaximumIntegerDigits
1029      */
1030     private byte    maxIntegerDigits = 40;
1031 
1032     /**
1033      * The minimum number of digits allowed in the integer portion of a
1034      * number.  <code>minimumIntegerDigits</code> must be less than or equal to
1035      * <code>maximumIntegerDigits</code>.
1036      * <p>
1037      * <strong>Note:</strong> This field exists only for serialization
1038      * compatibility with JDK 1.1.  In Java platform 2 v1.2 and higher, the new
1039      * <code>int</code> field <code>minimumIntegerDigits</code> is used instead.
1040      * When writing to a stream, <code>minIntegerDigits</code> is set to
1041      * <code>minimumIntegerDigits</code> or <code>Byte.MAX_VALUE</code>,
1042      * whichever is smaller.  When reading from a stream, this field is used
1043      * only if <code>serialVersionOnStream</code> is less than 1.
1044      *
1045      * @serial
1046      * @see #getMinimumIntegerDigits
1047      */
1048     private byte    minIntegerDigits = 1;
1049 
1050     /**
1051      * The maximum number of digits allowed in the fractional portion of a
1052      * number.  <code>maximumFractionDigits</code> must be greater than or equal to
1053      * <code>minimumFractionDigits</code>.
1054      * <p>
1055      * <strong>Note:</strong> This field exists only for serialization
1056      * compatibility with JDK 1.1.  In Java platform 2 v1.2 and higher, the new
1057      * <code>int</code> field <code>maximumFractionDigits</code> is used instead.
1058      * When writing to a stream, <code>maxFractionDigits</code> is set to
1059      * <code>maximumFractionDigits</code> or <code>Byte.MAX_VALUE</code>,
1060      * whichever is smaller.  When reading from a stream, this field is used
1061      * only if <code>serialVersionOnStream</code> is less than 1.
1062      *
1063      * @serial
1064      * @see #getMaximumFractionDigits
1065      */
1066     private byte    maxFractionDigits = 3;    // invariant, >= minFractionDigits
1067 
1068     /**
1069      * The minimum number of digits allowed in the fractional portion of a
1070      * number.  <code>minimumFractionDigits</code> must be less than or equal to
1071      * <code>maximumFractionDigits</code>.
1072      * <p>
1073      * <strong>Note:</strong> This field exists only for serialization
1074      * compatibility with JDK 1.1.  In Java platform 2 v1.2 and higher, the new
1075      * <code>int</code> field <code>minimumFractionDigits</code> is used instead.
1076      * When writing to a stream, <code>minFractionDigits</code> is set to
1077      * <code>minimumFractionDigits</code> or <code>Byte.MAX_VALUE</code>,
1078      * whichever is smaller.  When reading from a stream, this field is used
1079      * only if <code>serialVersionOnStream</code> is less than 1.
1080      *
1081      * @serial
1082      * @see #getMinimumFractionDigits
1083      */
1084     private byte    minFractionDigits = 0;
1085 
1086     /**
1087      * True if this format will parse numbers as integers only.
1088      *
1089      * @serial
1090      * @see #isParseIntegerOnly
1091      */
1092     private boolean parseIntegerOnly = false;
1093 
1094     // new fields for 1.2.  byte is too small for integer digits.
1095 
1096     /**
1097      * The maximum number of digits allowed in the integer portion of a
1098      * number.  <code>maximumIntegerDigits</code> must be greater than or equal to
1099      * <code>minimumIntegerDigits</code>.
1100      *
1101      * @serial
1102      * @since 1.2
1103      * @see #getMaximumIntegerDigits
1104      */
1105     private int    maximumIntegerDigits = 40;
1106 
1107     /**
1108      * The minimum number of digits allowed in the integer portion of a
1109      * number.  <code>minimumIntegerDigits</code> must be less than or equal to
1110      * <code>maximumIntegerDigits</code>.
1111      *
1112      * @serial
1113      * @since 1.2
1114      * @see #getMinimumIntegerDigits
1115      */
1116     private int    minimumIntegerDigits = 1;
1117 
1118     /**
1119      * The maximum number of digits allowed in the fractional portion of a
1120      * number.  <code>maximumFractionDigits</code> must be greater than or equal to
1121      * <code>minimumFractionDigits</code>.
1122      *
1123      * @serial
1124      * @since 1.2
1125      * @see #getMaximumFractionDigits
1126      */
1127     private int    maximumFractionDigits = 3;    // invariant, >= minFractionDigits
1128 
1129     /**
1130      * The minimum number of digits allowed in the fractional portion of a
1131      * number.  <code>minimumFractionDigits</code> must be less than or equal to
1132      * <code>maximumFractionDigits</code>.
1133      *
1134      * @serial
1135      * @since 1.2
1136      * @see #getMinimumFractionDigits
1137      */
1138     private int    minimumFractionDigits = 0;
1139 
1140     static final int currentSerialVersion = 1;
1141 
1142     /**
1143      * Describes the version of <code>NumberFormat</code> present on the stream.
1144      * Possible values are:
1145      * <ul>
1146      * <li><b>0</b> (or uninitialized): the JDK 1.1 version of the stream format.
1147      *     In this version, the <code>int</code> fields such as
1148      *     <code>maximumIntegerDigits</code> were not present, and the <code>byte</code>
1149      *     fields such as <code>maxIntegerDigits</code> are used instead.
1150      *
1151      * <li><b>1</b>: the 1.2 version of the stream format.  The values of the
1152      *     <code>byte</code> fields such as <code>maxIntegerDigits</code> are ignored,
1153      *     and the <code>int</code> fields such as <code>maximumIntegerDigits</code>
1154      *     are used instead.
1155      * </ul>
1156      * When streaming out a <code>NumberFormat</code>, the most recent format
1157      * (corresponding to the highest allowable <code>serialVersionOnStream</code>)
1158      * is always written.
1159      *
1160      * @serial
1161      * @since 1.2
1162      */
1163     private int serialVersionOnStream = currentSerialVersion;
1164 
1165     // Removed "implements Cloneable" clause.  Needs to update serialization
1166     // ID for backward compatibility.
1167     static final long serialVersionUID = -2308460125733713944L;
1168 
1169 
1170     //
1171     // class for AttributedCharacterIterator attributes
1172     //
1173     /**
1174      * Defines constants that are used as attribute keys in the
1175      * <code>AttributedCharacterIterator</code> returned
1176      * from <code>NumberFormat.formatToCharacterIterator</code> and as
1177      * field identifiers in <code>FieldPosition</code>.
1178      *
1179      * @since 1.4
1180      */
1181     public static class Field extends Format.Field {
1182 
1183         // Proclaim serial compatibility with 1.4 FCS
1184         private static final long serialVersionUID = 7494728892700160890L;
1185 
1186         // table of all instances in this class, used by readResolve
1187         private static final Map<String, Field> instanceMap = new HashMap<>(11);
1188 
1189         /**
1190          * Creates a Field instance with the specified
1191          * name.
1192          *
1193          * @param name Name of the attribute
1194          */
1195         protected Field(String name) {
1196             super(name);
1197             if (this.getClass() == NumberFormat.Field.class) {
1198                 instanceMap.put(name, this);
1199             }
1200         }
1201 
1202         /**
1203          * Resolves instances being deserialized to the predefined constants.
1204          *
1205          * @throws InvalidObjectException if the constant could not be resolved.
1206          * @return resolved NumberFormat.Field constant
1207          */
1208         @Override
1209         protected Object readResolve() throws InvalidObjectException {
1210             if (this.getClass() != NumberFormat.Field.class) {
1211                 throw new InvalidObjectException("subclass didn't correctly implement readResolve");
1212             }
1213 
1214             Object instance = instanceMap.get(getName());
1215             if (instance != null) {
1216                 return instance;
1217             } else {
1218                 throw new InvalidObjectException("unknown attribute name");
1219             }
1220         }
1221 
1222         /**
1223          * Constant identifying the integer field.
1224          */
1225         public static final Field INTEGER = new Field("integer");
1226 
1227         /**
1228          * Constant identifying the fraction field.
1229          */
1230         public static final Field FRACTION = new Field("fraction");
1231 
1232         /**
1233          * Constant identifying the exponent field.
1234          */
1235         public static final Field EXPONENT = new Field("exponent");
1236 
1237         /**
1238          * Constant identifying the decimal separator field.
1239          */
1240         public static final Field DECIMAL_SEPARATOR =
1241                             new Field("decimal separator");
1242 
1243         /**
1244          * Constant identifying the sign field.
1245          */
1246         public static final Field SIGN = new Field("sign");
1247 
1248         /**
1249          * Constant identifying the grouping separator field.
1250          */
1251         public static final Field GROUPING_SEPARATOR =
1252                             new Field("grouping separator");
1253 
1254         /**
1255          * Constant identifying the exponent symbol field.
1256          */
1257         public static final Field EXPONENT_SYMBOL = new
1258                             Field("exponent symbol");
1259 
1260         /**
1261          * Constant identifying the percent field.
1262          */
1263         public static final Field PERCENT = new Field("percent");
1264 
1265         /**
1266          * Constant identifying the permille field.
1267          */
1268         public static final Field PERMILLE = new Field("per mille");
1269 
1270         /**
1271          * Constant identifying the currency field.
1272          */
1273         public static final Field CURRENCY = new Field("currency");
1274 
1275         /**
1276          * Constant identifying the exponent sign field.
1277          */
1278         public static final Field EXPONENT_SIGN = new Field("exponent sign");
1279     }
1280 }