    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.text;
    018
    019import java.util.HashSet;
    020import java.util.Set;
    021import java.util.regex.Matcher;
    022import java.util.regex.Pattern;
    023
    024import org.apache.commons.lang3.ArrayUtils;
    025import org.apache.commons.lang3.StringUtils;
    026import org.apache.commons.lang3.Validate;
    027
    028/**
    029 * <p>
    030 * Operations on Strings that contain words.
    031 * </p>
    032 *
    033 * <p>
    034 * This class tries to handle {@code null} input gracefully. An exception will not be thrown for a
    035 * {@code null} input. Each method documents its behavior in more detail.
    036 * </p>
    037 *
    038 * @since 1.1
    039 */
    040public class WordUtils {
    041
    042    /**
    043     * <p>{@code WordUtils} instances should NOT be constructed in
    044     * standard programming. Instead, the class should be used as
    045     * {@code WordUtils.wrap("foo bar", 20);}.</p>
    046     *
    047     * <p>This constructor is public to permit tools that require a JavaBean
    048     * instance to operate.</p>
    049     */
    050    public WordUtils() {
    051      super();
    052    }
    053
    054    // Wrapping
    055    //--------------------------------------------------------------------------
    056    /**
    057     * <p>Wraps a single line of text, identifying words by {@code ' '}.</p>
    058     *
    059     * <p>New lines will be separated by the system property line separator.
    060     * Very long words, such as URLs will <i>not</i> be wrapped.</p>
    061     *
    062     * <p>Leading spaces on a new line are stripped.
    063     * Trailing spaces are not stripped.</p>
    064     *
    065     * <table border="1">
    066     *  <caption>Examples</caption>
    067     *  <tr>
    068     *   <th>input</th>
    069     *   <th>wrapLength</th>
    070     *   <th>result</th>
    071     *  </tr>
    072     *  <tr>
    073     *   <td>null</td>
    074     *   <td>*</td>
    075     *   <td>null</td>
    076     *  </tr>
    077     *  <tr>
    078     *   <td>""</td>
    079     *   <td>*</td>
    080     *   <td>""</td>
    081     *  </tr>
    082     *  <tr>
    083     *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
    084     *   <td>20</td>
    085     *   <td>"Here is one line of\ntext that is going\nto be wrapped after\n20 columns."</td>
    086     *  </tr>
    087     *  <tr>
    088     *   <td>"Click here to jump to the commons website - https://commons.apache.org"</td>
    089     *   <td>20</td>
    090     *   <td>"Click here to jump\nto the commons\nwebsite -\nhttps://commons.apache.org"</td>
    091     *  </tr>
    092     *  <tr>
    093     *   <td>"Click here, https://commons.apache.org, to jump to the commons website"</td>
    094     *   <td>20</td>
    095     *   <td>"Click here,\nhttps://commons.apache.org,\nto jump to the\ncommons website"</td>
    096     *  </tr>
    097     * </table>
    098     *
    099     * (assuming that '\n' is the systems line separator)
    100     *
    101     * @param str  the String to be word wrapped, may be null
    102     * @param wrapLength  the column to wrap the words at, less than 1 is treated as 1
    103     * @return a line with newlines inserted, {@code null} if null input
    104     */
    105    public static String wrap(final String str, final int wrapLength) {
    106        return wrap(str, wrapLength, null, false);
    107    }
    108
    109    /**
    110     * <p>Wraps a single line of text, identifying words by {@code ' '}.</p>
    111     *
    112     * <p>Leading spaces on a new line are stripped.
    113     * Trailing spaces are not stripped.</p>
    114     *
    115     * <table border="1">
    116     *  <caption>Examples</caption>
    117     *  <tr>
    118     *   <th>input</th>
    119     *   <th>wrapLength</th>
    120     *   <th>newLineString</th>
    121     *   <th>wrapLongWords</th>
    122     *   <th>result</th>
    123     *  </tr>
    124     *  <tr>
    125     *   <td>null</td>
    126     *   <td>*</td>
    127     *   <td>*</td>
    128     *   <td>true/false</td>
    129     *   <td>null</td>
    130     *  </tr>
    131     *  <tr>
    132     *   <td>""</td>
    133     *   <td>*</td>
    134     *   <td>*</td>
    135     *   <td>true/false</td>
    136     *   <td>""</td>
    137     *  </tr>
    138     *  <tr>
    139     *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
    140     *   <td>20</td>
    141     *   <td>"\n"</td>
    142     *   <td>true/false</td>
    143     *   <td>"Here is one line of\ntext that is going\nto be wrapped after\n20 columns."</td>
    144     *  </tr>
    145     *  <tr>
    146     *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
    147     *   <td>20</td>
    148     *   <td>"&lt;br /&gt;"</td>
    149     *   <td>true/false</td>
    150     *   <td>"Here is one line of&lt;br /&gt;text that is going&lt;
    151     *   br /&gt;to be wrapped after&lt;br /&gt;20 columns."</td>
    152     *  </tr>
    153     *  <tr>
    154     *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
    155     *   <td>20</td>
    156     *   <td>null</td>
    157     *   <td>true/false</td>
    158     *   <td>"Here is one line of" + systemNewLine + "text that is going"
    159     *   + systemNewLine + "to be wrapped after" + systemNewLine + "20 columns."</td>
    160     *  </tr>
    161     *  <tr>
    162     *   <td>"Click here to jump to the commons website - https://commons.apache.org"</td>
    163     *   <td>20</td>
    164     *   <td>"\n"</td>
    165     *   <td>false</td>
    166     *   <td>"Click here to jump\nto the commons\nwebsite -\nhttps://commons.apache.org"</td>
    167     *  </tr>
    168     *  <tr>
    169     *   <td>"Click here to jump to the commons website - https://commons.apache.org"</td>
    170     *   <td>20</td>
    171     *   <td>"\n"</td>
    172     *   <td>true</td>
    173     *   <td>"Click here to jump\nto the commons\nwebsite -\nhttp://commons.apach\ne.org"</td>
    174     *  </tr>
    175     * </table>
    176     *
    177     * @param str  the String to be word wrapped, may be null
    178     * @param wrapLength  the column to wrap the words at, less than 1 is treated as 1
    179     * @param newLineStr  the string to insert for a new line,
    180     *  {@code null} uses the system property line separator
    181     * @param wrapLongWords  true if long words (such as URLs) should be wrapped
    182     * @return a line with newlines inserted, {@code null} if null input
    183     */
    184    public static String wrap(final String str,
    185                              final int wrapLength,
    186                              final String newLineStr,
    187                              final boolean wrapLongWords) {
    188        return wrap(str, wrapLength, newLineStr, wrapLongWords, " ");
    189    }
    190
    191    /**
    192     * <p>Wraps a single line of text, identifying words by {@code wrapOn}.</p>
    193     *
    194     * <p>Leading spaces on a new line are stripped.
    195     * Trailing spaces are not stripped.</p>
    196     *
    197     * <table border="1">
    198     *  <caption>Examples</caption>
    199     *  <tr>
    200     *   <th>input</th>
    201     *   <th>wrapLength</th>
    202     *   <th>newLineString</th>
    203     *   <th>wrapLongWords</th>
    204     *   <th>wrapOn</th>
    205     *   <th>result</th>
    206     *  </tr>
    207     *  <tr>
    208     *   <td>null</td>
    209     *   <td>*</td>
    210     *   <td>*</td>
    211     *   <td>true/false</td>
    212     *   <td>*</td>
    213     *   <td>null</td>
    214     *  </tr>
    215     *  <tr>
    216     *   <td>""</td>
    217     *   <td>*</td>
    218     *   <td>*</td>
    219     *   <td>true/false</td>
    220     *   <td>*</td>
    221     *   <td>""</td>
    222     *  </tr>
    223     *  <tr>
    224     *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
    225     *   <td>20</td>
    226     *   <td>"\n"</td>
    227     *   <td>true/false</td>
    228     *   <td>" "</td>
    229     *   <td>"Here is one line of\ntext that is going\nto be wrapped after\n20 columns."</td>
    230     *  </tr>
    231     *  <tr>
    232     *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
    233     *   <td>20</td>
    234     *   <td>"&lt;br /&gt;"</td>
    235     *   <td>true/false</td>
    236     *   <td>" "</td>
    237     *   <td>"Here is one line of&lt;br /&gt;text that is going&lt;br /&gt;
    238     *   to be wrapped after&lt;br /&gt;20 columns."</td>
    239     *  </tr>
    240     *  <tr>
    241     *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
    242     *   <td>20</td>
    243     *   <td>null</td>
    244     *   <td>true/false</td>
    245     *   <td>" "</td>
    246     *   <td>"Here is one line of" + systemNewLine + "text that is going"
    247     *   + systemNewLine + "to be wrapped after" + systemNewLine + "20 columns."</td>
    248     *  </tr>
    249     *  <tr>
    250     *   <td>"Click here to jump to the commons website - https://commons.apache.org"</td>
    251     *   <td>20</td>
    252     *   <td>"\n"</td>
    253     *   <td>false</td>
    254     *   <td>" "</td>
    255     *   <td>"Click here to jump\nto the commons\nwebsite -\nhttps://commons.apache.org"</td>
    256     *  </tr>
    257     *  <tr>
    258     *   <td>"Click here to jump to the commons website - https://commons.apache.org"</td>
    259     *   <td>20</td>
    260     *   <td>"\n"</td>
    261     *   <td>true</td>
    262     *   <td>" "</td>
    263     *   <td>"Click here to jump\nto the commons\nwebsite -\nhttp://commons.apach\ne.org"</td>
    264     *  </tr>
    265     *  <tr>
    266     *   <td>"flammable/inflammable"</td>
    267     *   <td>20</td>
    268     *   <td>"\n"</td>
    269     *   <td>true</td>
    270     *   <td>"/"</td>
    271     *   <td>"flammable\ninflammable"</td>
    272     *  </tr>
    273     * </table>
    274     * @param str  the String to be word wrapped, may be null
    275     * @param wrapLength  the column to wrap the words at, less than 1 is treated as 1
    276     * @param newLineStr  the string to insert for a new line,
    277     *  {@code null} uses the system property line separator
    278     * @param wrapLongWords  true if long words (such as URLs) should be wrapped
    279     * @param wrapOn regex expression to be used as a breakable characters,
    280     *               if blank string is provided a space character will be used
    281     * @return a line with newlines inserted, {@code null} if null input
    282     */
    283    public static String wrap(final String str,
    284                              int wrapLength,
    285                              String newLineStr,
    286                              final boolean wrapLongWords,
    287                              String wrapOn) {
    288        if (str == null) {
    289            return null;
    290        }
    291        if (newLineStr == null) {
    292            newLineStr = System.lineSeparator();
    293        }
    294        if (wrapLength < 1) {
    295            wrapLength = 1;
    296        }
    297        if (StringUtils.isBlank(wrapOn)) {
    298            wrapOn = " ";
    299        }
    300        final Pattern patternToWrapOn = Pattern.compile(wrapOn);
    301        final int inputLineLength = str.length();
    302        int offset = 0;
    303        final StringBuilder wrappedLine = new StringBuilder(inputLineLength + 32);
    304        int matcherSize = -1;
    305
    306        while (offset < inputLineLength) {
    307            int spaceToWrapAt = -1;
    308            Matcher matcher = patternToWrapOn.matcher(str.substring(offset,
    309                    Math.min((int) Math.min(Integer.MAX_VALUE, offset + wrapLength + 1L), inputLineLength)));
    310            if (matcher.find()) {
    311                if (matcher.start() == 0) {
    312                    matcherSize = matcher.end() - matcher.start();
    313                    if (matcherSize != 0) {
    314                        offset += matcher.end();
    315                        continue;
    316                    }
    317                    offset += 1;
    318                }
    319                spaceToWrapAt = matcher.start() + offset;
    320            }
    321
    322            // only last line without leading spaces is left
    323            if (inputLineLength - offset <= wrapLength) {
    324                break;
    325            }
    326
    327            while (matcher.find()) {
    328                spaceToWrapAt = matcher.start() + offset;
    329            }
    330
    331            if (spaceToWrapAt >= offset) {
    332                // normal case
    333                wrappedLine.append(str, offset, spaceToWrapAt);
    334                wrappedLine.append(newLineStr);
    335                offset = spaceToWrapAt + 1;
    336
    337            } else {
    338                // really long word or URL
    339                if (wrapLongWords) {
    340                    if (matcherSize == 0) {
    341                        offset--;
    342                    }
    343                    // wrap really long word one line at a time
    344                    wrappedLine.append(str, offset, wrapLength + offset);
    345                    wrappedLine.append(newLineStr);
    346                    offset += wrapLength;
    347                    matcherSize = -1;
    348                } else {
    349                    // do not wrap really long word, just extend beyond limit
    350                    matcher = patternToWrapOn.matcher(str.substring(offset + wrapLength));
    351                    if (matcher.find()) {
    352                        matcherSize = matcher.end() - matcher.start();
    353                        spaceToWrapAt = matcher.start() + offset + wrapLength;
    354                    }
    355
    356                    if (spaceToWrapAt >= 0) {
    357                        if (matcherSize == 0 && offset != 0) {
    358                            offset--;
    359                        }
    360                        wrappedLine.append(str, offset, spaceToWrapAt);
    361                        wrappedLine.append(newLineStr);
    362                        offset = spaceToWrapAt + 1;
    363                    } else {
    364                        if (matcherSize == 0 && offset != 0) {
    365                            offset--;
    366                        }
    367                        wrappedLine.append(str, offset, str.length());
    368                        offset = inputLineLength;
    369                        matcherSize = -1;
    370                    }
    371                }
    372            }
    373        }
    374
    375        if (matcherSize == 0 && offset < inputLineLength) {
    376            offset--;
    377        }
    378
    379        // Whatever is left in line is short enough to just pass through
    380        wrappedLine.append(str, offset, str.length());
    381
    382        return wrappedLine.toString();
    383    }
    384
    385    // Capitalizing
    386    //-----------------------------------------------------------------------
    387    /**
    388     * <p>Capitalizes all the whitespace separated words in a String.
    389     * Only the first character of each word is changed. To convert the
    390     * rest of each word to lowercase at the same time,
    391     * use {@link #capitalizeFully(String)}.</p>
    392     *
    393     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
    394     * A {@code null} input String returns {@code null}.
    395     * Capitalization uses the Unicode title case, normally equivalent to
    396     * upper case.</p>
    397     *
    398     * <pre>
    399     * WordUtils.capitalize(null)        = null
    400     * WordUtils.capitalize("")          = ""
    401     * WordUtils.capitalize("i am FINE") = "I Am FINE"
    402     * </pre>
    403     *
    404     * @param str  the String to capitalize, may be null
    405     * @return capitalized String, {@code null} if null String input
    406     * @see #uncapitalize(String)
    407     * @see #capitalizeFully(String)
    408     */
    409    public static String capitalize(final String str) {
    410        return capitalize(str, null);
    411    }
    412
    413    /**
    414     * <p>Capitalizes all the delimiter separated words in a String.
    415     * Only the first character of each word is changed. To convert the
    416     * rest of each word to lowercase at the same time,
    417     * use {@link #capitalizeFully(String, char[])}.</p>
    418     *
    419     * <p>The delimiters represent a set of characters understood to separate words.
    420     * The first string character and the first non-delimiter character after a
    421     * delimiter will be capitalized.</p>
    422     *
    423     * <p>A {@code null} input String returns {@code null}.
    424     * Capitalization uses the Unicode title case, normally equivalent to
    425     * upper case.</p>
    426     *
    427     * <pre>
    428     * WordUtils.capitalize(null, *)            = null
    429     * WordUtils.capitalize("", *)              = ""
    430     * WordUtils.capitalize(*, new char[0])     = *
    431     * WordUtils.capitalize("i am fine", null)  = "I Am Fine"
    432     * WordUtils.capitalize("i aM.fine", {'.'}) = "I aM.Fine"
    433     * WordUtils.capitalize("i am fine", new char[]{}) = "I am fine"
    434     * </pre>
    435     *
    436     * @param str  the String to capitalize, may be null
    437     * @param delimiters  set of characters to determine capitalization, null means whitespace
    438     * @return capitalized String, {@code null} if null String input
    439     * @see #uncapitalize(String)
    440     * @see #capitalizeFully(String)
    441     */
    442    public static String capitalize(final String str, final char... delimiters) {
    443        if (StringUtils.isEmpty(str)) {
    444            return str;
    445        }
    446        final Set<Integer> delimiterSet = generateDelimiterSet(delimiters);
    447        final int strLen = str.length();
    448        final int[] newCodePoints = new int[strLen];
    449        int outOffset = 0;
    450
    451        boolean capitalizeNext = true;
    452        for (int index = 0; index < strLen;) {
    453            final int codePoint = str.codePointAt(index);
    454
    455            if (delimiterSet.contains(codePoint)) {
    456                capitalizeNext = true;
    457                newCodePoints[outOffset++] = codePoint;
    458                index += Character.charCount(codePoint);
    459            } else if (capitalizeNext) {
    460                final int titleCaseCodePoint = Character.toTitleCase(codePoint);
    461                newCodePoints[outOffset++] = titleCaseCodePoint;
    462                index += Character.charCount(titleCaseCodePoint);
    463                capitalizeNext = false;
    464            } else {
    465                newCodePoints[outOffset++] = codePoint;
    466                index += Character.charCount(codePoint);
    467            }
    468        }
    469        return new String(newCodePoints, 0, outOffset);
    470    }
    471
    472    //-----------------------------------------------------------------------
    473    /**
    474     * <p>Converts all the whitespace separated words in a String into capitalized words,
    475     * that is each word is made up of a titlecase character and then a series of
    476     * lowercase characters.</p>
    477     *
    478     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
    479     * A {@code null} input String returns {@code null}.
    480     * Capitalization uses the Unicode title case, normally equivalent to
    481     * upper case.</p>
    482     *
    483     * <pre>
    484     * WordUtils.capitalizeFully(null)        = null
    485     * WordUtils.capitalizeFully("")          = ""
    486     * WordUtils.capitalizeFully("i am FINE") = "I Am Fine"
    487     * </pre>
    488     *
    489     * @param str  the String to capitalize, may be null
    490     * @return capitalized String, {@code null} if null String input
    491     */
    492    public static String capitalizeFully(final String str) {
    493        return capitalizeFully(str, null);
    494    }
    495
    496    /**
    497     * <p>Converts all the delimiter separated words in a String into capitalized words,
    498     * that is each word is made up of a titlecase character and then a series of
    499     * lowercase characters.</p>
    500     *
    501     * <p>The delimiters represent a set of characters understood to separate words.
    502     * The first string character and the first non-delimiter character after a
    503     * delimiter will be capitalized.</p>
    504     *
    505     * <p>A {@code null} input String returns {@code null}.
    506     * Capitalization uses the Unicode title case, normally equivalent to
    507     * upper case.</p>
    508     *
    509     * <pre>
    510     * WordUtils.capitalizeFully(null, *)            = null
    511     * WordUtils.capitalizeFully("", *)              = ""
    512     * WordUtils.capitalizeFully(*, null)            = *
    513     * WordUtils.capitalizeFully(*, new char[0])     = *
    514     * WordUtils.capitalizeFully("i aM.fine", {'.'}) = "I am.Fine"
    515     * </pre>
    516     *
    517     * @param str  the String to capitalize, may be null
    518     * @param delimiters  set of characters to determine capitalization, null means whitespace
    519     * @return capitalized String, {@code null} if null String input
    520     */
    521    public static String capitalizeFully(String str, final char... delimiters) {
    522        if (StringUtils.isEmpty(str)) {
    523            return str;
    524        }
    525        str = str.toLowerCase();
    526        return capitalize(str, delimiters);
    527    }
    528
    529    //-----------------------------------------------------------------------
    530    /**
    531     * <p>Uncapitalizes all the whitespace separated words in a String.
    532     * Only the first character of each word is changed.</p>
    533     *
    534     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
    535     * A {@code null} input String returns {@code null}.</p>
    536     *
    537     * <pre>
    538     * WordUtils.uncapitalize(null)        = null
    539     * WordUtils.uncapitalize("")          = ""
    540     * WordUtils.uncapitalize("I Am FINE") = "i am fINE"
    541     * </pre>
    542     *
    543     * @param str  the String to uncapitalize, may be null
    544     * @return uncapitalized String, {@code null} if null String input
    545     * @see #capitalize(String)
    546     */
    547    public static String uncapitalize(final String str) {
    548        return uncapitalize(str, null);
    549    }
    550
    551    /**
    552     * <p>Uncapitalizes all the whitespace separated words in a String.
    553     * Only the first character of each word is changed.</p>
    554     *
    555     * <p>The delimiters represent a set of characters understood to separate words.
    556     * The first string character and the first non-delimiter character after a
    557     * delimiter will be uncapitalized.</p>
    558     *
    559     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
    560     * A {@code null} input String returns {@code null}.</p>
    561     *
    562     * <pre>
    563     * WordUtils.uncapitalize(null, *)            = null
    564     * WordUtils.uncapitalize("", *)              = ""
    565     * WordUtils.uncapitalize(*, null)            = *
    566     * WordUtils.uncapitalize(*, new char[0])     = *
    567     * WordUtils.uncapitalize("I AM.FINE", {'.'}) = "i AM.fINE"
    568     * WordUtils.uncapitalize("I am fine", new char[]{}) = "i am fine"
    569     * </pre>
    570     *
    571     * @param str  the String to uncapitalize, may be null
    572     * @param delimiters  set of characters to determine uncapitalization, null means whitespace
    573     * @return uncapitalized String, {@code null} if null String input
    574     * @see #capitalize(String)
    575     */
    576    public static String uncapitalize(final String str, final char... delimiters) {
    577        if (StringUtils.isEmpty(str)) {
    578            return str;
    579        }
    580        final Set<Integer> delimiterSet = generateDelimiterSet(delimiters);
    581        final int strLen = str.length();
    582        final int[] newCodePoints = new int[strLen];
    583        int outOffset = 0;
    584
    585        boolean uncapitalizeNext = true;
    586        for (int index = 0; index < strLen;) {
    587            final int codePoint = str.codePointAt(index);
    588
    589            if (delimiterSet.contains(codePoint)) {
    590                uncapitalizeNext = true;
    591                newCodePoints[outOffset++] = codePoint;
    592                index += Character.charCount(codePoint);
    593            } else if (uncapitalizeNext) {
    594                final int titleCaseCodePoint = Character.toLowerCase(codePoint);
    595                newCodePoints[outOffset++] = titleCaseCodePoint;
    596                index += Character.charCount(titleCaseCodePoint);
    597                uncapitalizeNext = false;
    598            } else {
    599                newCodePoints[outOffset++] = codePoint;
    600                index += Character.charCount(codePoint);
    601            }
    602        }
    603        return new String(newCodePoints, 0, outOffset);
    604    }
    605
    606    //-----------------------------------------------------------------------
    607    /**
    608     * <p>Swaps the case of a String using a word based algorithm.</p>
    609     *
    610     * <ul>
    611     *  <li>Upper case character converts to Lower case</li>
    612     *  <li>Title case character converts to Lower case</li>
    613     *  <li>Lower case character after Whitespace or at start converts to Title case</li>
    614     *  <li>Other Lower case character converts to Upper case</li>
    615     * </ul>
    616     *
    617     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
    618     * A {@code null} input String returns {@code null}.</p>
    619     *
    620     * <pre>
    621     * StringUtils.swapCase(null)                 = null
    622     * StringUtils.swapCase("")                   = ""
    623     * StringUtils.swapCase("The dog has a BONE") = "tHE DOG HAS A bone"
    624     * </pre>
    625     *
    626     * @param str  the String to swap case, may be null
    627     * @return The changed String, {@code null} if null String input
    628     */
    629    public static String swapCase(final String str) {
    630        if (StringUtils.isEmpty(str)) {
    631            return str;
    632        }
    633        final int strLen = str.length();
    634        final int[] newCodePoints = new int[strLen];
    635        int outOffset = 0;
    636        boolean whitespace = true;
    637        for (int index = 0; index < strLen;) {
    638            final int oldCodepoint = str.codePointAt(index);
    639            final int newCodePoint;
    640            if (Character.isUpperCase(oldCodepoint) || Character.isTitleCase(oldCodepoint)) {
    641                newCodePoint = Character.toLowerCase(oldCodepoint);
    642                whitespace = false;
    643            } else if (Character.isLowerCase(oldCodepoint)) {
    644                if (whitespace) {
    645                    newCodePoint = Character.toTitleCase(oldCodepoint);
    646                    whitespace = false;
    647                } else {
    648                    newCodePoint = Character.toUpperCase(oldCodepoint);
    649                }
    650            } else {
    651                whitespace = Character.isWhitespace(oldCodepoint);
    652                newCodePoint = oldCodepoint;
    653            }
    654            newCodePoints[outOffset++] = newCodePoint;
    655            index += Character.charCount(newCodePoint);
    656        }
    657        return new String(newCodePoints, 0, outOffset);
    658    }
    659
    660    //-----------------------------------------------------------------------
    661    /**
    662     * <p>Extracts the initial characters from each word in the String.</p>
    663     *
    664     * <p>All first characters after whitespace are returned as a new string.
    665     * Their case is not changed.</p>
    666     *
    667     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
    668     * A {@code null} input String returns {@code null}.</p>
    669     *
    670     * <pre>
    671     * WordUtils.initials(null)             = null
    672     * WordUtils.initials("")               = ""
    673     * WordUtils.initials("Ben John Lee")   = "BJL"
    674     * WordUtils.initials("Ben J.Lee")      = "BJ"
    675     * </pre>
    676     *
    677     * @param str  the String to get initials from, may be null
    678     * @return String of initial letters, {@code null} if null String input
    679     * @see #initials(String,char[])
    680     */
    681    public static String initials(final String str) {
    682        return initials(str, null);
    683    }
    684
    685    /**
    686     * <p>Extracts the initial characters from each word in the String.</p>
    687     *
    688     * <p>All first characters after the defined delimiters are returned as a new string.
    689     * Their case is not changed.</p>
    690     *
    691     * <p>If the delimiters array is null, then Whitespace is used.
    692     * Whitespace is defined by {@link Character#isWhitespace(char)}.
    693     * A {@code null} input String returns {@code null}.
    694     * An empty delimiter array returns an empty String.</p>
    695     *
    696     * <pre>
    697     * WordUtils.initials(null, *)                = null
    698     * WordUtils.initials("", *)                  = ""
    699     * WordUtils.initials("Ben John Lee", null)   = "BJL"
    700     * WordUtils.initials("Ben J.Lee", null)      = "BJ"
    701     * WordUtils.initials("Ben J.Lee", [' ','.']) = "BJL"
    702     * WordUtils.initials(*, new char[0])         = ""
    703     * </pre>
    704     *
    705     * @param str  the String to get initials from, may be null
    706     * @param delimiters  set of characters to determine words, null means whitespace
    707     * @return String of initial characters, {@code null} if null String input
    708     * @see #initials(String)
    709     */
    710    public static String initials(final String str, final char... delimiters) {
    711        if (StringUtils.isEmpty(str)) {
    712            return str;
    713        }
    714        if (delimiters != null && delimiters.length == 0) {
    715            return StringUtils.EMPTY;
    716        }
    717        final Set<Integer> delimiterSet = generateDelimiterSet(delimiters);
    718        final int strLen = str.length();
    719        final int[] newCodePoints = new int[strLen / 2 + 1];
    720        int count = 0;
    721        boolean lastWasGap = true;
    722        for (int i = 0; i < strLen;) {
    723            final int codePoint = str.codePointAt(i);
    724
    725            if (delimiterSet.contains(codePoint) || (delimiters == null && Character.isWhitespace(codePoint))) {
    726                lastWasGap = true;
    727            } else if (lastWasGap) {
    728                newCodePoints[count++] = codePoint;
    729                lastWasGap = false;
    730            }
    731
    732            i += Character.charCount(codePoint);
    733        }
    734        return new String(newCodePoints, 0, count);
    735    }
    736
    737    //-----------------------------------------------------------------------
    738    /**
    739     * <p>Checks if the String contains all words in the given array.</p>
    740     *
    741     * <p>
    742     * A {@code null} String will return {@code false}. A {@code null}, zero
    743     * length search array or if one element of array is null will return {@code false}.
    744     * </p>
    745     *
    746     * <pre>
    747     * WordUtils.containsAllWords(null, *)            = false
    748     * WordUtils.containsAllWords("", *)              = false
    749     * WordUtils.containsAllWords(*, null)            = false
    750     * WordUtils.containsAllWords(*, [])              = false
    751     * WordUtils.containsAllWords("abcd", "ab", "cd") = false
    752     * WordUtils.containsAllWords("abc def", "def", "abc") = true
    753     * </pre>
    754     *
    755     * @param word The CharSequence to check, may be null
    756     * @param words The array of String words to search for, may be null
    757     * @return {@code true} if all search words are found, {@code false} otherwise
    758     */
    759    public static boolean containsAllWords(final CharSequence word, final CharSequence... words) {
    760        if (StringUtils.isEmpty(word) || ArrayUtils.isEmpty(words)) {
    761            return false;
    762        }
    763        for (final CharSequence w : words) {
    764            if (StringUtils.isBlank(w)) {
    765                return false;
    766            }
    767            final Pattern p = Pattern.compile(".*\\b" + w + "\\b.*");
    768            if (!p.matcher(word).matches()) {
    769                return false;
    770            }
    771        }
    772        return true;
    773    }
    774
    775    //-----------------------------------------------------------------------
    776    /**
    777     * Is the character a delimiter.
    778     *
    779     * @param ch the character to check
    780     * @param delimiters the delimiters
    781     * @return true if it is a delimiter
    782     * @deprecated as of 1.2 and will be removed in 2.0
    783     */
    784    @Deprecated
    785    public static boolean isDelimiter(final char ch, final char[] delimiters) {
    786        if (delimiters == null) {
    787            return Character.isWhitespace(ch);
    788        }
    789        for (final char delimiter : delimiters) {
    790            if (ch == delimiter) {
    791                return true;
    792            }
    793        }
    794        return false;
    795    }
    796
    797  //-----------------------------------------------------------------------
    798    /**
    799     * Is the codePoint a delimiter.
    800     *
    801     * @param codePoint the codePint to check
    802     * @param delimiters the delimiters
    803     * @return true if it is a delimiter
    804     * @deprecated as of 1.2 and will be removed in 2.0
    805     */
    806    @Deprecated
    807    public static boolean isDelimiter(final int codePoint, final char[] delimiters) {
    808        if (delimiters == null) {
    809            return Character.isWhitespace(codePoint);
    810        }
    811        for (int index = 0; index < delimiters.length; index++) {
    812            final int delimiterCodePoint = Character.codePointAt(delimiters, index);
    813            if (delimiterCodePoint == codePoint) {
    814                return true;
    815            }
    816        }
    817        return false;
    818    }
    819
    820    //-----------------------------------------------------------------------
    821    /**
    822     * Abbreviates the words nicely.
    823     *
    824     * This method searches for the first space after the lower limit and abbreviates
    825     * the String there. It will also append any String passed as a parameter
    826     * to the end of the String. The upper limit can be specified to forcibly
    827     * abbreviate a String.
    828     *
    829     * @param str         the string to be abbreviated. If null is passed, null is returned.
    830     *                    If the empty String is passed, the empty string is returned.
    831     * @param lower       the lower limit.
    832     * @param upper       the upper limit; specify -1 if no limit is desired.
    833     *                    If the upper limit is lower than the lower limit, it will be
    834     *                    adjusted to be the same as the lower limit.
    835     * @param appendToEnd String to be appended to the end of the abbreviated string.
    836     *                    This is appended ONLY if the string was indeed abbreviated.
    837     *                    The append does not count towards the lower or upper limits.
    838     * @return The abbreviated String.
    839     *
    840     * <pre>
    841     * WordUtils.abbreviate("Now is the time for all good men", 0, 40, null));     = "Now"
    842     * WordUtils.abbreviate("Now is the time for all good men", 10, 40, null));    = "Now is the"
    843     * WordUtils.abbreviate("Now is the time for all good men", 20, 40, null));    = "Now is the time for all"
    844     * WordUtils.abbreviate("Now is the time for all good men", 0, 40, ""));       = "Now"
    845     * WordUtils.abbreviate("Now is the time for all good men", 10, 40, ""));      = "Now is the"
    846     * WordUtils.abbreviate("Now is the time for all good men", 20, 40, ""));      = "Now is the time for all"
    847     * WordUtils.abbreviate("Now is the time for all good men", 0, 40, " ..."));   = "Now ..."
    848     * WordUtils.abbreviate("Now is the time for all good men", 10, 40, " ..."));  = "Now is the ..."
    849     * WordUtils.abbreviate("Now is the time for all good men", 20, 40, " ..."));  = "Now is the time for all ..."
    850     * WordUtils.abbreviate("Now is the time for all good men", 0, -1, ""));       = "Now"
    851     * WordUtils.abbreviate("Now is the time for all good men", 10, -1, ""));      = "Now is the"
    852     * WordUtils.abbreviate("Now is the time for all good men", 20, -1, ""));      = "Now is the time for all"
    853     * WordUtils.abbreviate("Now is the time for all good men", 50, -1, ""));      = "Now is the time for all good men"
    854     * WordUtils.abbreviate("Now is the time for all good men", 1000, -1, ""));    = "Now is the time for all good men"
    855     * WordUtils.abbreviate("Now is the time for all good men", 9, -10, null));    = IllegalArgumentException
    856     * WordUtils.abbreviate("Now is the time for all good men", 10, 5, null));     = IllegalArgumentException
    857     * </pre>
    858     */
    859    public static String abbreviate(final String str, int lower, int upper, final String appendToEnd) {
    860        Validate.isTrue(upper >= -1, "upper value cannot be less than -1");
    861        Validate.isTrue(upper >= lower || upper == -1, "upper value is less than lower value");
    862
    863        if (StringUtils.isEmpty(str)) {
    864            return str;
    865        }
    866
    867        // if the lower value is greater than the length of the string,
    868        // set to the length of the string
    869        if (lower > str.length()) {
    870            lower = str.length();
    871        }
    872
    873        // if the upper value is -1 (i.e. no limit) or is greater
    874        // than the length of the string, set to the length of the string
    875        if (upper == -1 || upper > str.length()) {
    876            upper = str.length();
    877        }
    878
    879        final StringBuilder result = new StringBuilder();
    880        final int index = StringUtils.indexOf(str, " ", lower);
    881        if (index == -1) {
    882            result.append(str, 0, upper);
    883            // only if abbreviation has occurred do we append the appendToEnd value
    884            if (upper != str.length()) {
    885                result.append(StringUtils.defaultString(appendToEnd));
    886            }
    887        } else if (index > upper) {
    888            result.append(str, 0, upper);
    889            result.append(StringUtils.defaultString(appendToEnd));
    890        } else {
    891            result.append(str, 0, index);
    892            result.append(StringUtils.defaultString(appendToEnd));
    893        }
    894
    895        return result.toString();
    896    }
    897
    898    // -----------------------------------------------------------------------
    899    /**
    900     * <p>
    901     * Converts an array of delimiters to a hash set of code points. Code point of space(32) is added as the default
    902     * value if delimiters is null. The generated hash set provides O(1) lookup time.
    903     * </p>
    904     *
    905     * @param delimiters set of characters to determine capitalization, null means whitespace
    906     * @return Set<Integer>
    907     */
    908    private static Set<Integer> generateDelimiterSet(final char[] delimiters) {
    909        final Set<Integer> delimiterHashSet = new HashSet<>();
    910        if (delimiters == null || delimiters.length == 0) {
    911            if (delimiters == null) {
    912                delimiterHashSet.add(Character.codePointAt(new char[] {' '}, 0));
    913            }
    914
    915            return delimiterHashSet;
    916        }
    917
    918        for (int index = 0; index < delimiters.length; index++) {
    919            delimiterHashSet.add(Character.codePointAt(delimiters, index));
    920        }
    921        return delimiterHashSet;
    922    }
    923 }