    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.lang3.time;
    018
    019import java.io.IOException;
    020import java.io.ObjectInputStream;
    021import java.io.Serializable;
    022import java.text.DateFormat;
    023import java.text.DateFormatSymbols;
    024import java.text.FieldPosition;
    025import java.text.SimpleDateFormat;
    026import java.util.ArrayList;
    027import java.util.Calendar;
    028import java.util.Date;
    029import java.util.List;
    030import java.util.Locale;
    031import java.util.TimeZone;
    032import java.util.concurrent.ConcurrentHashMap;
    033import java.util.concurrent.ConcurrentMap;
    034
    035import org.apache.commons.lang3.ClassUtils;
    036import org.apache.commons.lang3.LocaleUtils;
    037import org.apache.commons.lang3.exception.ExceptionUtils;
    038
    039/**
    040 * FastDatePrinter is a fast and thread-safe version of
    041 * {@link java.text.SimpleDateFormat}.
    042 *
    043 * <p>To obtain a FastDatePrinter, use {@link FastDateFormat#getInstance(String, TimeZone, Locale)}
    044 * or another variation of the factory methods of {@link FastDateFormat}.</p>
    045 *
    046 * <p>Since FastDatePrinter is thread safe, you can use a static member instance:</p>
    047 * {@code
    048 *     private static final DatePrinter DATE_PRINTER = FastDateFormat.getInstance("yyyy-MM-dd");
    049 * }
    050 *
    051 * <p>This class can be used as a direct replacement to
    052 * {@link SimpleDateFormat} in most formatting situations.
    053 * This class is especially useful in multi-threaded server environments.
    054 * {@link SimpleDateFormat} is not thread-safe in any JDK version,
    055 * nor will it be as Sun have closed the bug/RFE.
    056 * </p>
    057 *
    058 * <p>Only formatting is supported by this class, but all patterns are compatible with
    059 * SimpleDateFormat (except time zones and some year patterns - see below).</p>
    060 *
    061 * <p>Java 1.4 introduced a new pattern letter, {@code 'Z'}, to represent
    062 * time zones in RFC822 format (eg. {@code +0800} or {@code -1100}).
    063 * This pattern letter can be used here (on all JDK versions).</p>
    064 *
    065 * <p>In addition, the pattern {@code 'ZZ'} has been made to represent
    066 * ISO 8601 extended format time zones (eg. {@code +08:00} or {@code -11:00}).
    067 * This introduces a minor incompatibility with Java 1.4, but at a gain of
    068 * useful functionality.</p>
    069 *
    070 * <p>Starting with JDK7, ISO 8601 support was added using the pattern {@code 'X'}.
    071 * To maintain compatibility, {@code 'ZZ'} will continue to be supported, but using
    072 * one of the {@code 'X'} formats is recommended.
    073 *
    074 * <p>Javadoc cites for the year pattern: <i>For formatting, if the number of
    075 * pattern letters is 2, the year is truncated to 2 digits; otherwise it is
    076 * interpreted as a number.</i> Starting with Java 1.7 a pattern of 'Y' or
    077 * 'YYY' will be formatted as '2003', while it was '03' in former Java
    078 * versions. FastDatePrinter implements the behavior of Java 7.</p>
    079 *
    080 * @since 3.2
    081 * @see FastDateParser
    082 */
    083public class FastDatePrinter implements DatePrinter, Serializable {
    084    // A lot of the speed in this class comes from caching, but some comes
    085    // from the special int to StringBuffer conversion.
    086    //
    087    // The following produces a padded 2-digit number:
    088    //   buffer.append((char)(value / 10 + '0'));
    089    //   buffer.append((char)(value % 10 + '0'));
    090    //
    091    // Note that the fastest append to StringBuffer is a single char (used here).
    092    // Note that Integer.toString() is not called, the conversion is simply
    093    // taking the value and adding (mathematically) the ASCII value for '0'.
    094    // So, don't change this code! It works and is very fast.
    095
    096    /**
    097     * Inner class to output a constant single character.
    098     */
    099    private static class CharacterLiteral implements Rule {
    100        private final char value;
    101
    102        /**
    103         * Constructs a new instance of {@link CharacterLiteral}
    104         * to hold the specified value.
    105         *
    106         * @param value the character literal
    107         */
    108        CharacterLiteral(final char value) {
    109            this.value = value;
    110        }
    111
    112        /**
    113         * {@inheritDoc}
    114         */
    115        @Override
    116        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    117            buffer.append(value);
    118        }
    119
    120        /**
    121         * {@inheritDoc}
    122         */
    123        @Override
    124        public int estimateLength() {
    125            return 1;
    126        }
    127    }
    128
    129    /**
    130     * Inner class to output the numeric day in week.
    131     */
    132    private static class DayInWeekField implements NumberRule {
    133        private final NumberRule rule;
    134
    135        DayInWeekField(final NumberRule rule) {
    136            this.rule = rule;
    137        }
    138
    139        @Override
    140        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    141            final int value = calendar.get(Calendar.DAY_OF_WEEK);
    142            rule.appendTo(buffer, value == Calendar.SUNDAY ? 7 : value - 1);
    143        }
    144
    145        @Override
    146        public void appendTo(final Appendable buffer, final int value) throws IOException {
    147            rule.appendTo(buffer, value);
    148        }
    149
    150        @Override
    151        public int estimateLength() {
    152            return rule.estimateLength();
    153        }
    154    }
    155
    156    /**
    157     * Inner class to output a time zone as a number {@code +/-HHMM}
    158     * or {@code +/-HH:MM}.
    159     */
    160    private static class Iso8601_Rule implements Rule {
    161
    162        // Sign TwoDigitHours or Z
    163        static final Iso8601_Rule ISO8601_HOURS = new Iso8601_Rule(3);
    164        // Sign TwoDigitHours Minutes or Z
    165        static final Iso8601_Rule ISO8601_HOURS_MINUTES = new Iso8601_Rule(5);
    166        // Sign TwoDigitHours : Minutes or Z
    167        static final Iso8601_Rule ISO8601_HOURS_COLON_MINUTES = new Iso8601_Rule(6);
    168
    169        /**
    170         * Factory method for Iso8601_Rules.
    171         *
    172         * @param tokenLen a token indicating the length of the TimeZone String to be formatted.
    173         * @return an Iso8601_Rule that can format TimeZone String of length {@code tokenLen}. If no such
    174         *          rule exists, an IllegalArgumentException will be thrown.
    175         */
    176        static Iso8601_Rule getRule(final int tokenLen) {
    177            switch (tokenLen) {
    178            case 1:
    179                return ISO8601_HOURS;
    180            case 2:
    181                return ISO8601_HOURS_MINUTES;
    182            case 3:
    183                return ISO8601_HOURS_COLON_MINUTES;
    184            default:
    185                throw new IllegalArgumentException("invalid number of X");
    186            }
    187        }
    188
    189        private final int length;
    190
    191        /**
    192         * Constructs an instance of {@code Iso8601_Rule} with the specified properties.
    193         *
    194         * @param length The number of characters in output (unless Z is output)
    195         */
    196        Iso8601_Rule(final int length) {
    197            this.length = length;
    198        }
    199
    200        /**
    201         * {@inheritDoc}
    202         */
    203        @Override
    204        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    205            int offset = calendar.get(Calendar.ZONE_OFFSET) + calendar.get(Calendar.DST_OFFSET);
    206            if (offset == 0) {
    207                buffer.append("Z");
    208                return;
    209            }
    210
    211            if (offset < 0) {
    212                buffer.append('-');
    213                offset = -offset;
    214            } else {
    215                buffer.append('+');
    216            }
    217
    218            final int hours = offset / (60 * 60 * 1000);
    219            appendDigits(buffer, hours);
    220
    221            if (length < 5) {
    222                return;
    223            }
    224
    225            if (length == 6) {
    226                buffer.append(':');
    227            }
    228
    229            final int minutes = offset / (60 * 1000) - 60 * hours;
    230            appendDigits(buffer, minutes);
    231        }
    232
    233        /**
    234         * {@inheritDoc}
    235         */
    236        @Override
    237        public int estimateLength() {
    238            return length;
    239        }
    240    }
    241    /**
    242     * Inner class defining a numeric rule.
    243     */
    244    private interface NumberRule extends Rule {
    245        /**
    246         * Appends the specified value to the output buffer based on the rule implementation.
    247         *
    248         * @param buffer the output buffer
    249         * @param value the value to be appended
    250         * @throws IOException if an I/O error occurs.
    251         */
    252        void appendTo(Appendable buffer, int value) throws IOException;
    253    }
    254    /**
    255     * Inner class to output a padded number.
    256     */
    257    private static final class PaddedNumberField implements NumberRule {
    258        // Note: This is final to avoid Spotbugs CT_CONSTRUCTOR_THROW
    259        private final int field;
    260        private final int size;
    261
    262        /**
    263         * Constructs an instance of {@link PaddedNumberField}.
    264         *
    265         * @param field the field
    266         * @param size size of the output field
    267         */
    268        PaddedNumberField(final int field, final int size) {
    269            if (size < 3) {
    270                // Should use UnpaddedNumberField or TwoDigitNumberField.
    271                throw new IllegalArgumentException();
    272            }
    273            this.field = field;
    274            this.size = size;
    275        }
    276
    277        /**
    278         * {@inheritDoc}
    279         */
    280        @Override
    281        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    282            appendTo(buffer, calendar.get(field));
    283        }
    284
    285        /**
    286         * {@inheritDoc}
    287         */
    288        @Override
    289        public /* final */ void appendTo(final Appendable buffer, final int value) throws IOException {
    290            // Checkstyle complains about redundant qualifier
    291            appendFullDigits(buffer, value, size);
    292        }
    293
    294        /**
    295         * {@inheritDoc}
    296         */
    297        @Override
    298        public int estimateLength() {
    299            return size;
    300        }
    301    }
    302    // Rules
    303    /**
    304     * Inner class defining a rule.
    305     */
    306    private interface Rule {
    307        /**
    308         * Appends the value of the specified calendar to the output buffer based on the rule implementation.
    309         *
    310         * @param buf the output buffer
    311         * @param calendar calendar to be appended
    312         * @throws IOException if an I/O error occurs.
    313         */
    314        void appendTo(Appendable buf, Calendar calendar) throws IOException;
    315
    316        /**
    317         * Returns the estimated length of the result.
    318         *
    319         * @return the estimated length
    320         */
    321        int estimateLength();
    322    }
    323
    324    /**
    325     * Inner class to output a constant string.
    326     */
    327    private static class StringLiteral implements Rule {
    328        private final String value;
    329
    330        /**
    331         * Constructs a new instance of {@link StringLiteral}
    332         * to hold the specified value.
    333         *
    334         * @param value the string literal
    335         */
    336        StringLiteral(final String value) {
    337            this.value = value;
    338        }
    339
    340        /**
    341         * {@inheritDoc}
    342         */
    343        @Override
    344        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    345            buffer.append(value);
    346        }
    347
    348        /**
    349         * {@inheritDoc}
    350         */
    351        @Override
    352        public int estimateLength() {
    353            return value.length();
    354        }
    355    }
    356    /**
    357     * Inner class to output one of a set of values.
    358     */
    359    private static class TextField implements Rule {
    360        private final int field;
    361        private final String[] values;
    362
    363        /**
    364         * Constructs an instance of {@link TextField}
    365         * with the specified field and values.
    366         *
    367         * @param field the field
    368         * @param values the field values
    369         */
    370        TextField(final int field, final String[] values) {
    371            this.field = field;
    372            this.values = values;
    373        }
    374
    375        /**
    376         * {@inheritDoc}
    377         */
    378        @Override
    379        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    380            buffer.append(values[calendar.get(field)]);
    381        }
    382
    383        /**
    384         * {@inheritDoc}
    385         */
    386        @Override
    387        public int estimateLength() {
    388            int max = 0;
    389            for (int i = values.length; --i >= 0;) {
    390                final int len = values[i].length();
    391                if (len > max) {
    392                    max = len;
    393                }
    394            }
    395            return max;
    396        }
    397    }
    398    /**
    399     * Inner class that acts as a compound key for time zone names.
    400     */
    401    private static class TimeZoneDisplayKey {
    402        private final TimeZone timeZone;
    403        private final int style;
    404        private final Locale locale;
    405
    406        /**
    407         * Constructs an instance of {@link TimeZoneDisplayKey} with the specified properties.
    408         *
    409         * @param timeZone the time zone
    410         * @param daylight adjust the style for daylight saving time if {@code true}
    411         * @param style the time zone style
    412         * @param locale the time zone locale
    413         */
    414        TimeZoneDisplayKey(final TimeZone timeZone,
    415                           final boolean daylight, final int style, final Locale locale) {
    416            this.timeZone = timeZone;
    417            if (daylight) {
    418                this.style = style | 0x80000000;
    419            } else {
    420                this.style = style;
    421            }
    422            this.locale = LocaleUtils.toLocale(locale);
    423        }
    424
    425        /**
    426         * {@inheritDoc}
    427         */
    428        @Override
    429        public boolean equals(final Object obj) {
    430            if (this == obj) {
    431                return true;
    432            }
    433            if (obj instanceof TimeZoneDisplayKey) {
    434                final TimeZoneDisplayKey other = (TimeZoneDisplayKey) obj;
    435                return
    436                    timeZone.equals(other.timeZone) &&
    437                    style == other.style &&
    438                    locale.equals(other.locale);
    439            }
    440            return false;
    441        }
    442
    443        /**
    444         * {@inheritDoc}
    445         */
    446        @Override
    447        public int hashCode() {
    448            return (style * 31 + locale.hashCode() ) * 31 + timeZone.hashCode();
    449        }
    450    }
    451    /**
    452     * Inner class to output a time zone name.
    453     */
    454    private static class TimeZoneNameRule implements Rule {
    455        private final Locale locale;
    456        private final int style;
    457        private final String standard;
    458        private final String daylight;
    459
    460        /**
    461         * Constructs an instance of {@link TimeZoneNameRule} with the specified properties.
    462         *
    463         * @param timeZone the time zone
    464         * @param locale the locale
    465         * @param style the style
    466         */
    467        TimeZoneNameRule(final TimeZone timeZone, final Locale locale, final int style) {
    468            this.locale = LocaleUtils.toLocale(locale);
    469            this.style = style;
    470            this.standard = getTimeZoneDisplay(timeZone, false, style, locale);
    471            this.daylight = getTimeZoneDisplay(timeZone, true, style, locale);
    472        }
    473
    474        /**
    475         * {@inheritDoc}
    476         */
    477        @Override
    478        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    479            final TimeZone zone = calendar.getTimeZone();
    480            final boolean daylight = calendar.get(Calendar.DST_OFFSET) != 0;
    481            buffer.append(getTimeZoneDisplay(zone, daylight, style, locale));
    482        }
    483
    484        /**
    485         * {@inheritDoc}
    486         */
    487        @Override
    488        public int estimateLength() {
    489            // We have no access to the Calendar object that will be passed to
    490            // appendTo so base estimate on the TimeZone passed to the
    491            // constructor
    492            return Math.max(standard.length(), daylight.length());
    493        }
    494    }
    495    /**
    496     * Inner class to output a time zone as a number {@code +/-HHMM}
    497     * or {@code +/-HH:MM}.
    498     */
    499    private static class TimeZoneNumberRule implements Rule {
    500        static final TimeZoneNumberRule INSTANCE_COLON = new TimeZoneNumberRule(true);
    501        static final TimeZoneNumberRule INSTANCE_NO_COLON = new TimeZoneNumberRule(false);
    502
    503        private final boolean colon;
    504
    505        /**
    506         * Constructs an instance of {@link TimeZoneNumberRule} with the specified properties.
    507         *
    508         * @param colon add colon between HH and MM in the output if {@code true}
    509         */
    510        TimeZoneNumberRule(final boolean colon) {
    511            this.colon = colon;
    512        }
    513
    514        /**
    515         * {@inheritDoc}
    516         */
    517        @Override
    518        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    519
    520            int offset = calendar.get(Calendar.ZONE_OFFSET) + calendar.get(Calendar.DST_OFFSET);
    521
    522            if (offset < 0) {
    523                buffer.append('-');
    524                offset = -offset;
    525            } else {
    526                buffer.append('+');
    527            }
    528
    529            final int hours = offset / (60 * 60 * 1000);
    530            appendDigits(buffer, hours);
    531
    532            if (colon) {
    533                buffer.append(':');
    534            }
    535
    536            final int minutes = offset / (60 * 1000) - 60 * hours;
    537            appendDigits(buffer, minutes);
    538        }
    539
    540        /**
    541         * {@inheritDoc}
    542         */
    543        @Override
    544        public int estimateLength() {
    545            return 5;
    546        }
    547    }
    548
    549    /**
    550     * Inner class to output the twelve hour field.
    551     */
    552    private static class TwelveHourField implements NumberRule {
    553        private final NumberRule rule;
    554
    555        /**
    556         * Constructs an instance of {@link TwelveHourField} with the specified
    557         * {@link NumberRule}.
    558         *
    559         * @param rule the rule
    560         */
    561        TwelveHourField(final NumberRule rule) {
    562            this.rule = rule;
    563        }
    564
    565        /**
    566         * {@inheritDoc}
    567         */
    568        @Override
    569        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    570            int value = calendar.get(Calendar.HOUR);
    571            if (value == 0) {
    572                value = calendar.getLeastMaximum(Calendar.HOUR) + 1;
    573            }
    574            rule.appendTo(buffer, value);
    575        }
    576
    577        /**
    578         * {@inheritDoc}
    579         */
    580        @Override
    581        public void appendTo(final Appendable buffer, final int value) throws IOException {
    582            rule.appendTo(buffer, value);
    583        }
    584
    585        /**
    586         * {@inheritDoc}
    587         */
    588        @Override
    589        public int estimateLength() {
    590            return rule.estimateLength();
    591        }
    592    }
    593
    594    /**
    595     * Inner class to output the twenty four hour field.
    596     */
    597    private static class TwentyFourHourField implements NumberRule {
    598        private final NumberRule rule;
    599
    600        /**
    601         * Constructs an instance of {@link TwentyFourHourField} with the specified
    602         * {@link NumberRule}.
    603         *
    604         * @param rule the rule
    605         */
    606        TwentyFourHourField(final NumberRule rule) {
    607            this.rule = rule;
    608        }
    609
    610        /**
    611         * {@inheritDoc}
    612         */
    613        @Override
    614        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    615            int value = calendar.get(Calendar.HOUR_OF_DAY);
    616            if (value == 0) {
    617                value = calendar.getMaximum(Calendar.HOUR_OF_DAY) + 1;
    618            }
    619            rule.appendTo(buffer, value);
    620        }
    621
    622        /**
    623         * {@inheritDoc}
    624         */
    625        @Override
    626        public void appendTo(final Appendable buffer, final int value) throws IOException {
    627            rule.appendTo(buffer, value);
    628        }
    629
    630        /**
    631         * {@inheritDoc}
    632         */
    633        @Override
    634        public int estimateLength() {
    635            return rule.estimateLength();
    636        }
    637    }
    638
    639    /**
    640     * Inner class to output a two digit month.
    641     */
    642    private static class TwoDigitMonthField implements NumberRule {
    643        static final TwoDigitMonthField INSTANCE = new TwoDigitMonthField();
    644
    645        /**
    646         * Constructs an instance of {@link TwoDigitMonthField}.
    647         */
    648        TwoDigitMonthField() {
    649        }
    650
    651        /**
    652         * {@inheritDoc}
    653         */
    654        @Override
    655        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    656            appendTo(buffer, calendar.get(Calendar.MONTH) + 1);
    657        }
    658
    659        /**
    660         * {@inheritDoc}
    661         */
    662        @Override
    663        public final void appendTo(final Appendable buffer, final int value) throws IOException {
    664            appendDigits(buffer, value);
    665        }
    666
    667        /**
    668         * {@inheritDoc}
    669         */
    670        @Override
    671        public int estimateLength() {
    672            return 2;
    673        }
    674    }
    675
    676    /**
    677     * Inner class to output a two digit number.
    678     */
    679    private static class TwoDigitNumberField implements NumberRule {
    680        private final int field;
    681
    682        /**
    683         * Constructs an instance of {@link TwoDigitNumberField} with the specified field.
    684         *
    685         * @param field the field
    686         */
    687        TwoDigitNumberField(final int field) {
    688            this.field = field;
    689        }
    690
    691        /**
    692         * {@inheritDoc}
    693         */
    694        @Override
    695        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    696            appendTo(buffer, calendar.get(field));
    697        }
    698
    699        /**
    700         * {@inheritDoc}
    701         */
    702        @Override
    703        public final void appendTo(final Appendable buffer, final int value) throws IOException {
    704            if (value < 100) {
    705                appendDigits(buffer, value);
    706            } else {
    707                appendFullDigits(buffer, value, 2);
    708            }
    709        }
    710
    711        /**
    712         * {@inheritDoc}
    713         */
    714        @Override
    715        public int estimateLength() {
    716            return 2;
    717        }
    718    }
    719
    720    /**
    721     * Inner class to output a two digit year.
    722     */
    723    private static class TwoDigitYearField implements NumberRule {
    724        static final TwoDigitYearField INSTANCE = new TwoDigitYearField();
    725
    726        /**
    727         * Constructs an instance of {@link TwoDigitYearField}.
    728         */
    729        TwoDigitYearField() {
    730        }
    731
    732        /**
    733         * {@inheritDoc}
    734         */
    735        @Override
    736        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    737            appendTo(buffer, calendar.get(Calendar.YEAR) % 100);
    738        }
    739
    740        /**
    741         * {@inheritDoc}
    742         */
    743        @Override
    744        public final void appendTo(final Appendable buffer, final int value) throws IOException {
    745            appendDigits(buffer, value % 100);
    746        }
    747
    748        /**
    749         * {@inheritDoc}
    750         */
    751        @Override
    752        public int estimateLength() {
    753            return 2;
    754        }
    755    }
    756
    757    /**
    758     * Inner class to output an unpadded month.
    759     */
    760    private static class UnpaddedMonthField implements NumberRule {
    761        static final UnpaddedMonthField INSTANCE = new UnpaddedMonthField();
    762
    763        /**
    764         * Constructs an instance of {@link UnpaddedMonthField}.
    765         */
    766        UnpaddedMonthField() {
    767        }
    768
    769        /**
    770         * {@inheritDoc}
    771         */
    772        @Override
    773        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    774            appendTo(buffer, calendar.get(Calendar.MONTH) + 1);
    775        }
    776
    777        /**
    778         * {@inheritDoc}
    779         */
    780        @Override
    781        public final void appendTo(final Appendable buffer, final int value) throws IOException {
    782            if (value < 10) {
    783                buffer.append((char) (value + '0'));
    784            } else {
    785                appendDigits(buffer, value);
    786            }
    787        }
    788
    789        /**
    790         * {@inheritDoc}
    791         */
    792        @Override
    793        public int estimateLength() {
    794            return 2;
    795        }
    796    }
    797
    798    /**
    799     * Inner class to output an unpadded number.
    800     */
    801    private static class UnpaddedNumberField implements NumberRule {
    802        private final int field;
    803
    804        /**
    805         * Constructs an instance of {@link UnpaddedNumberField} with the specified field.
    806         *
    807         * @param field the field
    808         */
    809        UnpaddedNumberField(final int field) {
    810            this.field = field;
    811        }
    812
    813        /**
    814         * {@inheritDoc}
    815         */
    816        @Override
    817        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    818            appendTo(buffer, calendar.get(field));
    819        }
    820
    821        /**
    822         * {@inheritDoc}
    823         */
    824        @Override
    825        public final void appendTo(final Appendable buffer, final int value) throws IOException {
    826            if (value < 10) {
    827                buffer.append((char) (value + '0'));
    828            } else if (value < 100) {
    829                appendDigits(buffer, value);
    830            } else {
    831               appendFullDigits(buffer, value, 1);
    832            }
    833        }
    834
    835        /**
    836         * {@inheritDoc}
    837         */
    838        @Override
    839        public int estimateLength() {
    840            return 4;
    841        }
    842    }
    843
    844    /**
    845     * Inner class to output the numeric day in week.
    846     */
    847    private static class WeekYear implements NumberRule {
    848        private final NumberRule rule;
    849
    850        WeekYear(final NumberRule rule) {
    851            this.rule = rule;
    852        }
    853
    854        @Override
    855        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
    856            rule.appendTo(buffer, calendar.getWeekYear());
    857        }
    858
    859        @Override
    860        public void appendTo(final Appendable buffer, final int value) throws IOException {
    861            rule.appendTo(buffer, value);
    862        }
    863
    864        @Override
    865        public int estimateLength() {
    866            return rule.estimateLength();
    867        }
    868    }
    869
    870    /** Empty array. */
    871    private static final Rule[] EMPTY_RULE_ARRAY = {};
    872
    873    /**
    874     * Required for serialization support.
    875     *
    876     * @see java.io.Serializable
    877     */
    878    private static final long serialVersionUID = 1L;
    879
    880    /**
    881     * FULL locale dependent date or time style.
    882     */
    883    public static final int FULL = DateFormat.FULL;
    884
    885    /**
    886     * LONG locale dependent date or time style.
    887     */
    888    public static final int LONG = DateFormat.LONG;
    889
    890    /**
    891     * MEDIUM locale dependent date or time style.
    892     */
    893    public static final int MEDIUM = DateFormat.MEDIUM;
    894
    895    /**
    896     * SHORT locale dependent date or time style.
    897     */
    898    public static final int SHORT = DateFormat.SHORT;
    899
    900    private static final int MAX_DIGITS = 10; // log10(Integer.MAX_VALUE) ~= 9.3
    901
    902    private static final ConcurrentMap<TimeZoneDisplayKey, String> cTimeZoneDisplayCache =
    903        new ConcurrentHashMap<>(7);
    904
    905    /**
    906     * Appends two digits to the given buffer.
    907     *
    908     * @param buffer the buffer to append to.
    909     * @param value the value to append digits from.
    910     * @throws IOException If an I/O error occurs
    911     */
    912    private static void appendDigits(final Appendable buffer, final int value) throws IOException {
    913        buffer.append((char) (value / 10 + '0'));
    914        buffer.append((char) (value % 10 + '0'));
    915    }
    916
    917    /**
    918     * Appends all digits to the given buffer.
    919     *
    920     * @param buffer the buffer to append to.
    921     * @param value the value to append digits from.
    922     * @param minFieldWidth Minimum field width.
    923     * @throws IOException If an I/O error occurs
    924     */
    925    private static void appendFullDigits(final Appendable buffer, int value, int minFieldWidth) throws IOException {
    926        // specialized paths for 1 to 4 digits -> avoid the memory allocation from the temporary work array
    927        // see LANG-1248
    928        if (value < 10000) {
    929            // less memory allocation path works for four digits or less
    930
    931            int nDigits = 4;
    932            if (value < 1000) {
    933                --nDigits;
    934                if (value < 100) {
    935                    --nDigits;
    936                    if (value < 10) {
    937                        --nDigits;
    938                    }
    939                }
    940            }
    941            // left zero pad
    942            for (int i = minFieldWidth - nDigits; i > 0; --i) {
    943                buffer.append('0');
    944            }
    945
    946            switch (nDigits) {
    947            case 4:
    948                buffer.append((char) (value / 1000 + '0'));
    949                value %= 1000;
    950            case 3:
    951                if (value >= 100) {
    952                    buffer.append((char) (value / 100 + '0'));
    953                    value %= 100;
    954                } else {
    955                    buffer.append('0');
    956                }
    957            case 2:
    958                if (value >= 10) {
    959                    buffer.append((char) (value / 10 + '0'));
    960                    value %= 10;
    961                } else {
    962                    buffer.append('0');
    963                }
    964            case 1:
    965                buffer.append((char) (value + '0'));
    966            }
    967        } else {
    968            // more memory allocation path works for any digits
    969
    970            // build up decimal representation in reverse
    971            final char[] work = new char[MAX_DIGITS];
    972            int digit = 0;
    973            while (value != 0) {
    974                work[digit++] = (char) (value % 10 + '0');
    975                value /= 10;
    976            }
    977
    978            // pad with zeros
    979            while (digit < minFieldWidth) {
    980                buffer.append('0');
    981                --minFieldWidth;
    982            }
    983
    984            // reverse
    985            while (--digit >= 0) {
    986                buffer.append(work[digit]);
    987            }
    988        }
    989    }
    990
    991    /**
    992     * Gets the time zone display name, using a cache for performance.
    993     *
    994     * @param tz  the zone to query
    995     * @param daylight  true if daylight savings
    996     * @param style  the style to use {@code TimeZone.LONG} or {@code TimeZone.SHORT}
    997     * @param locale  the locale to use
    998     * @return the textual name of the time zone
    999     */
    1000    static String getTimeZoneDisplay(final TimeZone tz, final boolean daylight, final int style, final Locale locale) {
    1001        final TimeZoneDisplayKey key = new TimeZoneDisplayKey(tz, daylight, style, locale);
    1002        // This is a very slow call, so cache the results.
    1003        return cTimeZoneDisplayCache.computeIfAbsent(key, k -> tz.getDisplayName(daylight, style, locale));
    1004    }
    1005
    1006    /**
    1007     * The pattern.
    1008     */
    1009    private final String pattern;
    1010
    1011    /**
    1012     * The time zone.
    1013     */
    1014    private final TimeZone timeZone;
    1015
    1016    /**
    1017     * The locale.
    1018     */
    1019    private final Locale locale;
    1020
    1021    /**
    1022     * The parsed rules.
    1023     */
    1024    private transient Rule[] rules;
    1025
    1026    /**
    1027     * The estimated maximum length.
    1028     */
    1029    private transient int maxLengthEstimate;
    1030
    1031    // Constructor
    1032    /**
    1033     * Constructs a new FastDatePrinter.
    1034     * Use {@link FastDateFormat#getInstance(String, TimeZone, Locale)}  or another variation of the
    1035     * factory methods of {@link FastDateFormat} to get a cached FastDatePrinter instance.
    1036     *
    1037     * @param pattern  {@link java.text.SimpleDateFormat} compatible pattern
    1038     * @param timeZone  non-null time zone to use
    1039     * @param locale  non-null locale to use
    1040     * @throws NullPointerException if pattern, timeZone, or locale is null.
    1041     */
    1042    protected FastDatePrinter(final String pattern, final TimeZone timeZone, final Locale locale) {
    1043        this.pattern = pattern;
    1044        this.timeZone = timeZone;
    1045        this.locale = LocaleUtils.toLocale(locale);
    1046        init();
    1047    }
    1048
    1049    /**
    1050     * Performs the formatting by applying the rules to the
    1051     * specified calendar.
    1052     *
    1053     * @param calendar  the calendar to format
    1054     * @param buf  the buffer to format into
    1055     * @param <B> the Appendable class type, usually StringBuilder or StringBuffer.
    1056     * @return the specified string buffer
    1057     */
    1058    private <B extends Appendable> B applyRules(final Calendar calendar, final B buf) {
    1059        try {
    1060            for (final Rule rule : rules) {
    1061                rule.appendTo(buf, calendar);
    1062            }
    1063        } catch (final IOException ioe) {
    1064            ExceptionUtils.asRuntimeException(ioe);
    1065        }
    1066        return buf;
    1067    }
    1068
    1069    /**
    1070     * Performs the formatting by applying the rules to the
    1071     * specified calendar.
    1072     *
    1073     * @param calendar the calendar to format
    1074     * @param buf the buffer to format into
    1075     * @return the specified string buffer
    1076     *
    1077     * @deprecated use {@link #format(Calendar)} or {@link #format(Calendar, Appendable)}
    1078     */
    1079    @Deprecated
    1080    protected StringBuffer applyRules(final Calendar calendar, final StringBuffer buf) {
    1081        return (StringBuffer) applyRules(calendar, (Appendable) buf);
    1082    }
    1083
    1084    /**
    1085     * Creates a String representation of the given Calendar by applying the rules of this printer to it.
    1086     * @param c the Calendar to apply the rules to.
    1087     * @return a String representation of the given Calendar.
    1088     */
    1089    private String applyRulesToString(final Calendar c) {
    1090        return applyRules(c, new StringBuilder(maxLengthEstimate)).toString();
    1091    }
    1092
    1093    // Basics
    1094    /**
    1095     * Compares two objects for equality.
    1096     *
    1097     * @param obj  the object to compare to
    1098     * @return {@code true} if equal
    1099     */
    1100    @Override
    1101    public boolean equals(final Object obj) {
    1102        if (!(obj instanceof FastDatePrinter)) {
    1103            return false;
    1104        }
    1105        final FastDatePrinter other = (FastDatePrinter) obj;
    1106        return pattern.equals(other.pattern)
    1107            && timeZone.equals(other.timeZone)
    1108            && locale.equals(other.locale);
    1109    }
    1110
    1111    /* (non-Javadoc)
    1112     * @see org.apache.commons.lang3.time.DatePrinter#format(java.util.Calendar)
    1113     */
    1114    @Override
    1115    public String format(final Calendar calendar) {
    1116        return format(calendar, new StringBuilder(maxLengthEstimate)).toString();
    1117    }
    1118
    1119    /* (non-Javadoc)
    1120     * @see org.apache.commons.lang3.time.DatePrinter#format(java.util.Calendar, Appendable)
    1121     */
    1122    @Override
    1123    public <B extends Appendable> B format(Calendar calendar, final B buf) {
    1124        // do not pass in calendar directly, this will cause TimeZone of FastDatePrinter to be ignored
    1125        if (!calendar.getTimeZone().equals(timeZone)) {
    1126            calendar = (Calendar) calendar.clone();
    1127            calendar.setTimeZone(timeZone);
    1128        }
    1129        return applyRules(calendar, buf);
    1130    }
    1131
    1132    /* (non-Javadoc)
    1133     * @see org.apache.commons.lang3.time.DatePrinter#format(java.util.Calendar, StringBuffer)
    1134     */
    1135    @Override
    1136    public StringBuffer format(final Calendar calendar, final StringBuffer buf) {
    1137        // do not pass in calendar directly, this will cause TimeZone of FastDatePrinter to be ignored
    1138        return format(calendar.getTime(), buf);
    1139    }
    1140
    1141    /* (non-Javadoc)
    1142     * @see org.apache.commons.lang3.time.DatePrinter#format(java.util.Date)
    1143     */
    1144    @Override
    1145    public String format(final Date date) {
    1146        final Calendar c = newCalendar();
    1147        c.setTime(date);
    1148        return applyRulesToString(c);
    1149    }
    1150
    1151    /* (non-Javadoc)
    1152     * @see org.apache.commons.lang3.time.DatePrinter#format(java.util.Date, Appendable)
    1153     */
    1154    @Override
    1155    public <B extends Appendable> B format(final Date date, final B buf) {
    1156        final Calendar c = newCalendar();
    1157        c.setTime(date);
    1158        return applyRules(c, buf);
    1159    }
    1160
    1161    /* (non-Javadoc)
    1162     * @see org.apache.commons.lang3.time.DatePrinter#format(java.util.Date, StringBuffer)
    1163     */
    1164    @Override
    1165    public StringBuffer format(final Date date, final StringBuffer buf) {
    1166        final Calendar c = newCalendar();
    1167        c.setTime(date);
    1168        return (StringBuffer) applyRules(c, (Appendable) buf);
    1169    }
    1170
    1171    /* (non-Javadoc)
    1172     * @see org.apache.commons.lang3.time.DatePrinter#format(long)
    1173     */
    1174    @Override
    1175    public String format(final long millis) {
    1176        final Calendar c = newCalendar();
    1177        c.setTimeInMillis(millis);
    1178        return applyRulesToString(c);
    1179    }
    1180
    1181    /* (non-Javadoc)
    1182     * @see org.apache.commons.lang3.time.DatePrinter#format(long, Appendable)
    1183     */
    1184    @Override
    1185    public <B extends Appendable> B format(final long millis, final B buf) {
    1186        final Calendar c = newCalendar();
    1187        c.setTimeInMillis(millis);
    1188        return applyRules(c, buf);
    1189    }
    1190
    1191    /* (non-Javadoc)
    1192     * @see org.apache.commons.lang3.time.DatePrinter#format(long, StringBuffer)
    1193     */
    1194    @Override
    1195    public StringBuffer format(final long millis, final StringBuffer buf) {
    1196        final Calendar c = newCalendar();
    1197        c.setTimeInMillis(millis);
    1198        return (StringBuffer) applyRules(c, (Appendable) buf);
    1199    }
    1200
    1201    /**
    1202     * Formats a {@link Date}, {@link Calendar} or
    1203     * {@link Long} (milliseconds) object.
    1204     * @since 3.5
    1205     * @param obj  the object to format
    1206     * @return The formatted value.
    1207     */
    1208    String format(final Object obj) {
    1209        if (obj instanceof Date) {
    1210            return format((Date) obj);
    1211        }
    1212        if (obj instanceof Calendar) {
    1213            return format((Calendar) obj);
    1214        }
    1215        if (obj instanceof Long) {
    1216            return format(((Long) obj).longValue());
    1217        }
    1218        throw new IllegalArgumentException("Unknown class: " + ClassUtils.getName(obj, "<null>"));
    1219    }
    1220
    1221    // Format methods
    1222    /**
    1223     * Formats a {@link Date}, {@link Calendar} or
    1224     * {@link Long} (milliseconds) object.
    1225     * @deprecated Use {{@link #format(Date)}, {{@link #format(Calendar)}, {{@link #format(long)}.
    1226     * @param obj  the object to format
    1227     * @param toAppendTo  the buffer to append to
    1228     * @param pos  the position - ignored
    1229     * @return the buffer passed in
    1230     */
    1231    @Deprecated
    1232    @Override
    1233    public StringBuffer format(final Object obj, final StringBuffer toAppendTo, final FieldPosition pos) {
    1234        if (obj instanceof Date) {
    1235            return format((Date) obj, toAppendTo);
    1236        }
    1237        if (obj instanceof Calendar) {
    1238            return format((Calendar) obj, toAppendTo);
    1239        }
    1240        if (obj instanceof Long) {
    1241            return format(((Long) obj).longValue(), toAppendTo);
    1242        }
    1243        throw new IllegalArgumentException("Unknown class: " + ClassUtils.getName(obj, "<null>"));
    1244    }
    1245
    1246    /* (non-Javadoc)
    1247     * @see org.apache.commons.lang3.time.DatePrinter#getLocale()
    1248     */
    1249    @Override
    1250    public Locale getLocale() {
    1251        return locale;
    1252    }
    1253
    1254    /**
    1255     * Gets an estimate for the maximum string length that the
    1256     * formatter will produce.
    1257     *
    1258     * <p>The actual formatted length will almost always be less than or
    1259     * equal to this amount.</p>
    1260     *
    1261     * @return the maximum formatted length
    1262     */
    1263    public int getMaxLengthEstimate() {
    1264        return maxLengthEstimate;
    1265    }
    1266
    1267    // Accessors
    1268    /* (non-Javadoc)
    1269     * @see org.apache.commons.lang3.time.DatePrinter#getPattern()
    1270     */
    1271    @Override
    1272    public String getPattern() {
    1273        return pattern;
    1274    }
    1275
    1276    /* (non-Javadoc)
    1277     * @see org.apache.commons.lang3.time.DatePrinter#getTimeZone()
    1278     */
    1279    @Override
    1280    public TimeZone getTimeZone() {
    1281        return timeZone;
    1282    }
    1283
    1284    /**
    1285     * Returns a hash code compatible with equals.
    1286     *
    1287     * @return a hash code compatible with equals
    1288     */
    1289    @Override
    1290    public int hashCode() {
    1291        return pattern.hashCode() + 13 * (timeZone.hashCode() + 13 * locale.hashCode());
    1292    }
    1293
    1294    /**
    1295     * Initializes the instance for first use.
    1296     */
    1297    private void init() {
    1298        final List<Rule> rulesList = parsePattern();
    1299        rules = rulesList.toArray(EMPTY_RULE_ARRAY);
    1300
    1301        int len = 0;
    1302        for (int i = rules.length; --i >= 0;) {
    1303            len += rules[i].estimateLength();
    1304        }
    1305
    1306        maxLengthEstimate = len;
    1307    }
    1308
    1309    /**
    1310     * Creates a new Calendar instance.
    1311     * @return a new Calendar instance.
    1312     */
    1313    private Calendar newCalendar() {
    1314        return Calendar.getInstance(timeZone, locale);
    1315    }
    1316
    1317    // Parse the pattern
    1318    /**
    1319     * Returns a list of Rules given a pattern.
    1320     *
    1321     * @return a {@link List} of Rule objects
    1322     * @throws IllegalArgumentException if pattern is invalid
    1323     */
    1324    protected List<Rule> parsePattern() {
    1325        final DateFormatSymbols symbols = new DateFormatSymbols(locale);
    1326        final List<Rule> rules = new ArrayList<>();
    1327
    1328        final String[] ERAs = symbols.getEras();
    1329        final String[] months = symbols.getMonths();
    1330        final String[] shortMonths = symbols.getShortMonths();
    1331        final String[] weekdays = symbols.getWeekdays();
    1332        final String[] shortWeekdays = symbols.getShortWeekdays();
    1333        final String[] AmPmStrings = symbols.getAmPmStrings();
    1334
    1335        final int length = pattern.length();
    1336        final int[] indexRef = new int[1];
    1337
    1338        for (int i = 0; i < length; i++) {
    1339            indexRef[0] = i;
    1340            final String token = parseToken(pattern, indexRef);
    1341            i = indexRef[0];
    1342
    1343            final int tokenLen = token.length();
    1344            if (tokenLen == 0) {
    1345                break;
    1346            }
    1347
    1348            Rule rule;
    1349            final char c = token.charAt(0);
    1350
    1351            switch (c) {
    1352            case 'G': // era designator (text)
    1353                rule = new TextField(Calendar.ERA, ERAs);
    1354                break;
    1355            case 'y': // year (number)
    1356            case 'Y': // week year
    1357                if (tokenLen == 2) {
    1358                    rule = TwoDigitYearField.INSTANCE;
    1359                } else {
    1360                    rule = selectNumberRule(Calendar.YEAR, Math.max(tokenLen, 4));
    1361                }
    1362                if (c == 'Y') {
    1363                    rule = new WeekYear((NumberRule) rule);
    1364                }
    1365                break;
    1366            case 'M': // month in year (text and number)
    1367                if (tokenLen >= 4) {
    1368                    rule = new TextField(Calendar.MONTH, months);
    1369                } else if (tokenLen == 3) {
    1370                    rule = new TextField(Calendar.MONTH, shortMonths);
    1371                } else if (tokenLen == 2) {
    1372                    rule = TwoDigitMonthField.INSTANCE;
    1373                } else {
    1374                    rule = UnpaddedMonthField.INSTANCE;
    1375                }
    1376                break;
    1377            case 'L': // month in year (text and number)
    1378                if (tokenLen >= 4) {
    1379                    rule = new TextField(Calendar.MONTH, CalendarUtils.getInstance(locale).getStandaloneLongMonthNames());
    1380                } else if (tokenLen == 3) {
    1381                    rule = new TextField(Calendar.MONTH, CalendarUtils.getInstance(locale).getStandaloneShortMonthNames());
    1382                } else if (tokenLen == 2) {
    1383                    rule = TwoDigitMonthField.INSTANCE;
    1384                } else {
    1385                    rule = UnpaddedMonthField.INSTANCE;
    1386                }
    1387                break;
    1388            case 'd': // day in month (number)
    1389                rule = selectNumberRule(Calendar.DAY_OF_MONTH, tokenLen);
    1390                break;
    1391            case 'h': // hour in am/pm (number, 1..12)
    1392                rule = new TwelveHourField(selectNumberRule(Calendar.HOUR, tokenLen));
    1393                break;
    1394            case 'H': // hour in day (number, 0..23)
    1395                rule = selectNumberRule(Calendar.HOUR_OF_DAY, tokenLen);
    1396                break;
    1397            case 'm': // minute in hour (number)
    1398                rule = selectNumberRule(Calendar.MINUTE, tokenLen);
    1399                break;
    1400            case 's': // second in minute (number)
    1401                rule = selectNumberRule(Calendar.SECOND, tokenLen);
    1402                break;
    1403            case 'S': // millisecond (number)
    1404                rule = selectNumberRule(Calendar.MILLISECOND, tokenLen);
    1405                break;
    1406            case 'E': // day in week (text)
    1407                rule = new TextField(Calendar.DAY_OF_WEEK, tokenLen < 4 ? shortWeekdays : weekdays);
    1408                break;
    1409            case 'u': // day in week (number)
    1410                rule = new DayInWeekField(selectNumberRule(Calendar.DAY_OF_WEEK, tokenLen));
    1411                break;
    1412            case 'D': // day in year (number)
    1413                rule = selectNumberRule(Calendar.DAY_OF_YEAR, tokenLen);
    1414                break;
    1415            case 'F': // day of week in month (number)
    1416                rule = selectNumberRule(Calendar.DAY_OF_WEEK_IN_MONTH, tokenLen);
    1417                break;
    1418            case 'w': // week in year (number)
    1419                rule = selectNumberRule(Calendar.WEEK_OF_YEAR, tokenLen);
    1420                break;
    1421            case 'W': // week in month (number)
    1422                rule = selectNumberRule(Calendar.WEEK_OF_MONTH, tokenLen);
    1423                break;
    1424            case 'a': // am/pm marker (text)
    1425                rule = new TextField(Calendar.AM_PM, AmPmStrings);
    1426                break;
    1427            case 'k': // hour in day (1..24)
    1428                rule = new TwentyFourHourField(selectNumberRule(Calendar.HOUR_OF_DAY, tokenLen));
    1429                break;
    1430            case 'K': // hour in am/pm (0..11)
    1431                rule = selectNumberRule(Calendar.HOUR, tokenLen);
    1432                break;
    1433            case 'X': // ISO 8601
    1434                rule = Iso8601_Rule.getRule(tokenLen);
    1435                break;
    1436            case 'z': // time zone (text)
    1437                if (tokenLen >= 4) {
    1438                    rule = new TimeZoneNameRule(timeZone, locale, TimeZone.LONG);
    1439                } else {
    1440                    rule = new TimeZoneNameRule(timeZone, locale, TimeZone.SHORT);
    1441                }
    1442                break;
    1443            case 'Z': // time zone (value)
    1444                if (tokenLen == 1) {
    1445                    rule = TimeZoneNumberRule.INSTANCE_NO_COLON;
    1446                } else if (tokenLen == 2) {
    1447                    rule = Iso8601_Rule.ISO8601_HOURS_COLON_MINUTES;
    1448                } else {
    1449                    rule = TimeZoneNumberRule.INSTANCE_COLON;
    1450                }
    1451                break;
    1452            case '\'': // literal text
    1453                final String sub = token.substring(1);
    1454                if (sub.length() == 1) {
    1455                    rule = new CharacterLiteral(sub.charAt(0));
    1456                } else {
    1457                    rule = new StringLiteral(sub);
    1458                }
    1459                break;
    1460            default:
    1461                throw new IllegalArgumentException("Illegal pattern component: " + token);
    1462            }
    1463
    1464            rules.add(rule);
    1465        }
    1466
    1467        return rules;
    1468    }
    1469
    1470    /**
    1471     * Performs the parsing of tokens.
    1472     *
    1473     * @param pattern  the pattern
    1474     * @param indexRef  index references
    1475     * @return parsed token
    1476     */
    1477    protected String parseToken(final String pattern, final int[] indexRef) {
    1478        final StringBuilder buf = new StringBuilder();
    1479
    1480        int i = indexRef[0];
    1481        final int length = pattern.length();
    1482
    1483        char c = pattern.charAt(i);
    1484        if (c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z') {
    1485            // Scan a run of the same character, which indicates a time
    1486            // pattern.
    1487            buf.append(c);
    1488
    1489            while (i + 1 < length) {
    1490                final char peek = pattern.charAt(i + 1);
    1491                if (peek != c) {
    1492                    break;
    1493                }
    1494                buf.append(c);
    1495                i++;
    1496            }
    1497        } else {
    1498            // This will identify token as text.
    1499            buf.append('\'');
    1500
    1501            boolean inLiteral = false;
    1502
    1503            for (; i < length; i++) {
    1504                c = pattern.charAt(i);
    1505
    1506                if (c == '\'') {
    1507                    if (i + 1 < length && pattern.charAt(i + 1) == '\'') {
    1508                        // '' is treated as escaped '
    1509                        i++;
    1510                        buf.append(c);
    1511                    } else {
    1512                        inLiteral = !inLiteral;
    1513                    }
    1514                } else if (!inLiteral &&
    1515                         (c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z')) {
    1516                    i--;
    1517                    break;
    1518                } else {
    1519                    buf.append(c);
    1520                }
    1521            }
    1522        }
    1523
    1524        indexRef[0] = i;
    1525        return buf.toString();
    1526    }
    1527
    1528    // Serializing
    1529    /**
    1530     * Create the object after serialization. This implementation reinitializes the
    1531     * transient properties.
    1532     *
    1533     * @param in ObjectInputStream from which the object is being deserialized.
    1534     * @throws IOException if there is an IO issue.
    1535     * @throws ClassNotFoundException if a class cannot be found.
    1536     */
    1537    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
    1538        in.defaultReadObject();
    1539        init();
    1540    }
    1541
    1542    /**
    1543     * Gets an appropriate rule for the padding required.
    1544     *
    1545     * @param field  the field to get a rule for
    1546     * @param padding  the padding required
    1547     * @return a new rule with the correct padding
    1548     */
    1549    protected NumberRule selectNumberRule(final int field, final int padding) {
    1550        switch (padding) {
    1551        case 1:
    1552            return new UnpaddedNumberField(field);
    1553        case 2:
    1554            return new TwoDigitNumberField(field);
    1555        default:
    1556            return new PaddedNumberField(field, padding);
    1557        }
    1558    }
    1559
    1560    /**
    1561     * Gets a debugging string version of this formatter.
    1562     *
    1563     * @return a debugging string
    1564     */
    1565    @Override
    1566    public String toString() {
    1567        return "FastDatePrinter[" + pattern + "," + locale + "," + timeZone.getID() + "]";
    1568    }
    1569}