/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *      https://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.commons.text;
  
  import java.util.HashSet;
  import java.util.Locale;
  import java.util.Set;
  import java.util.function.IntUnaryOperator;
  import java.util.function.Predicate;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.apache.commons.lang3.ArrayUtils;
  import org.apache.commons.lang3.StringUtils;
  import org.apache.commons.lang3.Strings;
  import org.apache.commons.lang3.Validate;
  
  /**
   * Operations on Strings that contain words.
   *
   * <p>
   * This class tries to handle {@code null} input gracefully. An exception will not be thrown for a
   * {@code null} input. Each method documents its behavior in more detail.
   * </p>
   *
   * @since 1.1
   */
  public class WordUtils {
  
      /**
       * Abbreviates the words nicely.
       * <p>
       * This method searches for the first space after the lower limit and abbreviates the String there. It will also append any String passed as a parameter to
       * the end of the String. The upper limit can be specified to forcibly abbreviate a String.
       * </p>
       *
       * <pre>
       * WordUtils.abbreviate("Now is the time for all good men", 0, 40, null));     = "Now"
       * WordUtils.abbreviate("Now is the time for all good men", 10, 40, null));    = "Now is the"
       * WordUtils.abbreviate("Now is the time for all good men", 20, 40, null));    = "Now is the time for all"
       * WordUtils.abbreviate("Now is the time for all good men", 0, 40, ""));       = "Now"
       * WordUtils.abbreviate("Now is the time for all good men", 10, 40, ""));      = "Now is the"
       * WordUtils.abbreviate("Now is the time for all good men", 20, 40, ""));      = "Now is the time for all"
       * WordUtils.abbreviate("Now is the time for all good men", 0, 40, " ..."));   = "Now ..."
       * WordUtils.abbreviate("Now is the time for all good men", 10, 40, " ..."));  = "Now is the ..."
       * WordUtils.abbreviate("Now is the time for all good men", 20, 40, " ..."));  = "Now is the time for all ..."
       * WordUtils.abbreviate("Now is the time for all good men", 0, -1, ""));       = "Now"
       * WordUtils.abbreviate("Now is the time for all good men", 10, -1, ""));      = "Now is the"
       * WordUtils.abbreviate("Now is the time for all good men", 20, -1, ""));      = "Now is the time for all"
       * WordUtils.abbreviate("Now is the time for all good men", 50, -1, ""));      = "Now is the time for all good men"
       * WordUtils.abbreviate("Now is the time for all good men", 1000, -1, ""));    = "Now is the time for all good men"
       * WordUtils.abbreviate("Now is the time for all good men", 9, -10, null));    = Throws {@link IllegalArgumentException}
       * WordUtils.abbreviate("Now is the time for all good men", 10, 5, null));     = Throws {@link IllegalArgumentException}
       * </pre>
       *
       * @param str         The string to be abbreviated. If null is passed, null is returned. If the empty String is passed, the empty string is returned.
       * @param lower       The lower limit; negative value is treated as zero.
       * @param upper       The upper limit; specify -1 if no limit is desired. The upper limit cannot be lower than the lower limit.
       * @param appendToEnd The String to be appended to the end of the abbreviated string. This is appended ONLY if the string was indeed abbreviated. The append
       *                    does not count towards the lower or upper limits.
       * @return The abbreviated String.
       */
      public static String abbreviate(final String str, int lower, int upper, final String appendToEnd) {
          Validate.isTrue(upper >= -1, "upper value cannot be less than -1");
          Validate.isTrue(upper >= lower || upper == -1, "upper value is less than lower value");
          if (StringUtils.isEmpty(str)) {
              return str;
          }
          // if the lower value is greater than the length of the string,
          // set to the length of the string
          if (lower > str.length()) {
              lower = str.length();
          }
          // if the upper value is -1 (i.e. no limit) or is greater
          // than the length of the string, set to the length of the string
          if (upper == -1 || upper > str.length()) {
              upper = str.length();
          }
          final StringBuilder result = new StringBuilder();
          final int index = Strings.CS.indexOf(str, " ", lower);
          if (index == -1) {
              result.append(str, 0, upper);
              // only if abbreviation has occurred do we append the appendToEnd value
              if (upper != str.length()) {
                  result.append(StringUtils.defaultString(appendToEnd));
             }
         } else {
             result.append(str, 0, Math.min(index, upper));
             result.append(StringUtils.defaultString(appendToEnd));
         }
         return result.toString();
     }
 
     /**
      * Applies a function to the first character of each word in a String.
      * <p>
      * This is used by {@link #capitalize(String, char...)} and {@link #uncapitalize(String, char...)}. The {@code transform} function is applied to the first
      * code point of each word; all other code points are passed through unchanged.
      * </p>
      *
      * @param str        The String to transform, may be null.
      * @param delimiters The set of characters to determine word boundaries, null means whitespace.
      * @param transform  The casing function to apply to the first code point of each word (e.g., {@code Character::toTitleCase} or
      *                   {@code Character::toLowerCase}).
      * @return The transformed String, or {@code null}/{@code ""} if the input is null/empty.
      */
     private static String applyWordCaseTransform(final String str, final char[] delimiters, final IntUnaryOperator transform) {
         if (StringUtils.isEmpty(str)) {
             return str;
         }
         final Predicate<Integer> isDelimiter = generateIsDelimiterFunction(delimiters);
         final int strLen = str.length();
         final int[] newCodePoints = new int[strLen];
         int outOffset = 0;
         boolean transformNext = true;
         for (int index = 0; index < strLen;) {
             final int codePoint = str.codePointAt(index);
             if (isDelimiter.test(codePoint)) {
                 transformNext = true;
                 newCodePoints[outOffset++] = codePoint;
                 index += Character.charCount(codePoint);
             } else if (transformNext) {
                 final int transformed = transform.applyAsInt(codePoint);
                 newCodePoints[outOffset++] = transformed;
                 index += Character.charCount(transformed);
                 transformNext = false;
             } else {
                 newCodePoints[outOffset++] = codePoint;
                 index += Character.charCount(codePoint);
             }
         }
         return new String(newCodePoints, 0, outOffset);
     }
 
     /**
      * Capitalizes all the whitespace separated words in a String. Only the first character of each word is changed. To convert the rest of each word to
      * lowercase at the same time, use {@link #capitalizeFully(String)}.
      * <p>
      * Whitespace is defined by {@link Character#isWhitespace(char)}. A {@code null} input String returns {@code null}. Capitalization uses the Unicode title
      * case, normally equivalent to upper case.
      * </p>
      *
      * <pre>
      * WordUtils.capitalize(null)        = null
      * WordUtils.capitalize("")          = ""
      * WordUtils.capitalize("i am FINE") = "I Am FINE"
      * </pre>
      *
      * @param str The String to capitalize, may be null.
      * @return A new Capitalized String, or {@code null} if null String input.
      * @see #uncapitalize(String)
      * @see #capitalizeFully(String)
      */
     public static String capitalize(final String str) {
         return capitalize(str, null);
     }
 
     /**
      * Capitalizes all the delimiter separated words in a String. Only the first character of each word is changed. To convert the rest of each word to
      * lowercase at the same time, use {@link #capitalizeFully(String, char[])}.
      * <p>
      * The delimiters represent a set of characters understood to separate words. The first string character and the first non-delimiter character after a
      * delimiter will be capitalized.
      * </p>
      * <p>
      * A {@code null} input String returns {@code null}. Capitalization uses the Unicode title case, normally equivalent to upper case.
      * </p>
      *
      * <pre>
      * WordUtils.capitalize(null, *)            = null
      * WordUtils.capitalize("", *)              = ""
      * WordUtils.capitalize(*, new char[0])     = *
      * WordUtils.capitalize("i am fine", null)  = "I Am Fine"
      * WordUtils.capitalize("i aM.fine", {'.'}) = "I aM.Fine"
      * WordUtils.capitalize("i am fine", new char[]{}) = "I am fine"
      * </pre>
      *
      * @param str        The String to capitalize, may be null.
      * @param delimiters The Set of characters to determine capitalization, null means whitespace.
      * @return A new Capitalized String, or {@code null} if null String input.
      * @see #uncapitalize(String)
      * @see #capitalizeFully(String)
      */
     public static String capitalize(final String str, final char... delimiters) {
         return applyWordCaseTransform(str, delimiters, Character::toTitleCase);
     }
 
     /**
      * Converts all the whitespace separated words in a String into capitalized words,
      * that is each word is made up of a titlecase character and then a series of
      * lowercase characters.
      *
      * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
      * A {@code null} input String returns {@code null}.
      * Capitalization uses the Unicode title case, normally equivalent to
      * upper case.</p>
      *
      * <pre>
      * WordUtils.capitalizeFully(null)        = null
      * WordUtils.capitalizeFully("")          = ""
      * WordUtils.capitalizeFully("i am FINE") = "I Am Fine"
      * </pre>
      *
      * @param str  The String to capitalize, may be null.
      * @return A new capitalized String, or {@code null} if null String input.
      */
     public static String capitalizeFully(final String str) {
         return capitalizeFully(str, null);
     }
 
     /**
      * Converts all the delimiter separated words in a String into capitalized words,
      * that is each word is made up of a titlecase character and then a series of
      * lowercase characters.
      *
      * <p>The delimiters represent a set of characters understood to separate words.
      * The first string character and the first non-delimiter character after a
      * delimiter will be capitalized.</p>
      *
      * <p>A {@code null} input String returns {@code null}.
      * Capitalization uses the Unicode title case, normally equivalent to
      * upper case.</p>
      *
      * <pre>
      * WordUtils.capitalizeFully(null, *)            = null
      * WordUtils.capitalizeFully("", *)              = ""
      * WordUtils.capitalizeFully(*, null)            = *
      * WordUtils.capitalizeFully(*, new char[0])     = *
      * WordUtils.capitalizeFully("i aM.fine", {'.'}) = "I am.Fine"
      * </pre>
      *
      * @param str  The String to capitalize, may be null.
      * @param delimiters  The Set of characters to determine capitalization, null means whitespace.
      * @return A new capitalized String, or {@code null} if null String input.
      */
     public static String capitalizeFully(final String str, final char... delimiters) {
         return StringUtils.isEmpty(str) ? str : capitalize(str.toLowerCase(Locale.ROOT), delimiters);
     }
 
     /**
      * Checks if the String contains all words in the given array.
      *
      * <p>
      * A {@code null} String will return {@code false}. A {@code null}, zero
      * length search array or if one element of array is null will return {@code false}.
      * </p>
      *
      * <pre>
      * WordUtils.containsAllWords(null, *)            = false
      * WordUtils.containsAllWords("", *)              = false
      * WordUtils.containsAllWords(*, null)            = false
      * WordUtils.containsAllWords(*, [])              = false
      * WordUtils.containsAllWords("abcd", "ab", "cd") = false
      * WordUtils.containsAllWords("abc def", "def", "abc") = true
      * </pre>
      *
      * @param word The CharSequence to check, may be null.
      * @param words The array of String words to search for, may be null.
      * @return {@code true} if all search words are found, {@code false} otherwise.
      */
     public static boolean containsAllWords(final CharSequence word, final CharSequence... words) {
         if (StringUtils.isEmpty(word) || ArrayUtils.isEmpty(words)) {
             return false;
         }
         for (final CharSequence w : words) {
             if (StringUtils.isBlank(w)) {
                 return false;
             }
             final Pattern p = Pattern.compile(".*\\b" + Pattern.quote(w.toString()) + "\\b.*", Pattern.DOTALL);
             if (!p.matcher(word).matches()) {
                 return false;
             }
         }
         return true;
     }
 
     /**
      * Given the array of delimiters supplied; returns a function determining whether a character code point is a delimiter.
      * The function provides O(1) lookup time.
      * Whitespace is defined by {@link Character#isWhitespace(char)} and is used as the defaultvalue if delimiters is null.
      *
      * @param delimiters The set of characters to determine delimiters, null means whitespace.
      * @return A Predicate<Integer> taking a code point value as an argument and returning true if a delimiter.
      */
     private static Predicate<Integer> generateIsDelimiterFunction(final char[] delimiters) {
         final Predicate<Integer> isDelimiter;
         if (delimiters == null || delimiters.length == 0) {
             isDelimiter = delimiters == null ? Character::isWhitespace : c -> false;
         } else {
             final Set<Integer> delimiterSet = new HashSet<>();
             for (int index = 0; index < delimiters.length; index++) {
                 delimiterSet.add(Character.codePointAt(delimiters, index));
             }
             isDelimiter = delimiterSet::contains;
         }
         return isDelimiter;
     }
 
     /**
      * Extracts the initial characters from each word in the String.
      * <p>
      * All first characters after whitespace are returned as a new string. Their case is not changed.
      * </p>
      * <p>
      * Whitespace is defined by {@link Character#isWhitespace(char)}. A {@code null} input String returns {@code null}.
      * </p>
      *
      * <pre>
      * WordUtils.initials(null)             = null
      * WordUtils.initials("")               = ""
      * WordUtils.initials("Ben John Lee")   = "BJL"
      * WordUtils.initials("Ben J.Lee")      = "BJ"
      * </pre>
      *
      * @param str The String to get initials from, may be null.
      * @return A new String of initial letters, or {@code null} if null String input.
      * @see #initials(String,char[])
      */
     public static String initials(final String str) {
         return initials(str, null);
     }
 
     /**
      * Extracts the initial characters from each word in the String.
      * <p>
      * All first characters after the defined delimiters are returned as a new string. Their case is not changed.
      * </p>
      * <p>
      * If the delimiters array is null, then Whitespace is used. Whitespace is defined by {@link Character#isWhitespace(char)}. A {@code null} input String
      * returns {@code null}. An empty delimiter array returns an empty String.
      * </p>
      *
      * <pre>
      * WordUtils.initials(null, *)                = null
      * WordUtils.initials("", *)                  = ""
      * WordUtils.initials("Ben John Lee", null)   = "BJL"
      * WordUtils.initials("Ben J.Lee", null)      = "BJ"
      * WordUtils.initials("Ben J.Lee", [' ','.']) = "BJL"
      * WordUtils.initials(*, new char[0])         = ""
      * </pre>
      *
      * @param str        The String to get initials from, may be null.
      * @param delimiters The Set of characters to determine words, null means whitespace.
      * @return String of initial characters, or {@code null} if null String input.
      * @see #initials(String)
      */
     public static String initials(final String str, final char... delimiters) {
         if (StringUtils.isEmpty(str)) {
             return str;
         }
         if (delimiters != null && delimiters.length == 0) {
             return StringUtils.EMPTY;
         }
         final Predicate<Integer> isDelimiter = generateIsDelimiterFunction(delimiters);
         final int strLen = str.length();
         final int[] newCodePoints = new int[strLen / 2 + 1];
         int count = 0;
         boolean lastWasGap = true;
         for (int i = 0; i < strLen;) {
             final int codePoint = str.codePointAt(i);
             if (isDelimiter.test(codePoint)) {
                 lastWasGap = true;
             } else if (lastWasGap) {
                 newCodePoints[count++] = codePoint;
                 lastWasGap = false;
             }
             i += Character.charCount(codePoint);
         }
         return new String(newCodePoints, 0, count);
     }
 
     /**
      * Is the character a delimiter.
      *
      * @param ch         The character to check.
      * @param delimiters The delimiters.
      * @return true if it is a delimiter.
      * @deprecated as of 1.2 and will be removed in 2.0.
      */
     @Deprecated
     public static boolean isDelimiter(final char ch, final char[] delimiters) {
         if (delimiters == null) {
             return Character.isWhitespace(ch);
         }
         for (final char delimiter : delimiters) {
             if (ch == delimiter) {
                 return true;
             }
         }
         return false;
     }
 
     /**
      * Is the codePoint a delimiter.
      *
      * @param codePoint  The codePint to check.
      * @param delimiters The delimiters.
      * @return true if it is a delimiter.
      * @deprecated as of 1.2 and will be removed in 2.0.
      */
     @Deprecated
     public static boolean isDelimiter(final int codePoint, final char[] delimiters) {
         if (delimiters == null) {
             return Character.isWhitespace(codePoint);
         }
         for (int index = 0; index < delimiters.length; index++) {
             final int delimiterCodePoint = Character.codePointAt(delimiters, index);
             if (delimiterCodePoint == codePoint) {
                 return true;
             }
         }
         return false;
     }
 
     /**
      * Swaps the case of a String using a word based algorithm.
      * <ul>
      * <li>Upper case character converts to Lower case</li>
      * <li>Title case character converts to Lower case</li>
      * <li>Lower case character after Whitespace or at start converts to Title case</li>
      * <li>Other Lower case character converts to Upper case</li>
      * </ul>
      * <p>
      * Whitespace is defined by {@link Character#isWhitespace(char)}. A {@code null} input String returns {@code null}.
      * </p>
      *
      * <pre>
      * StringUtils.swapCase(null)                 = null
      * StringUtils.swapCase("")                   = ""
      * StringUtils.swapCase("The dog has a BONE") = "tHE DOG HAS A bone"
      * </pre>
      *
      * @param str The String to swap case, may be null.
      * @return The changed String, or {@code null} if null String input.
      */
     public static String swapCase(final String str) {
         if (StringUtils.isEmpty(str)) {
             return str;
         }
         final int strLen = str.length();
         final int[] newCodePoints = new int[strLen];
         int outOffset = 0;
         boolean whitespace = true;
         for (int index = 0; index < strLen;) {
             final int oldCodepoint = str.codePointAt(index);
             final int newCodePoint;
             if (Character.isUpperCase(oldCodepoint) || Character.isTitleCase(oldCodepoint)) {
                 newCodePoint = Character.toLowerCase(oldCodepoint);
                 whitespace = false;
             } else if (Character.isLowerCase(oldCodepoint)) {
                 if (whitespace) {
                     newCodePoint = Character.toTitleCase(oldCodepoint);
                     whitespace = false;
                 } else {
                     newCodePoint = Character.toUpperCase(oldCodepoint);
                 }
             } else {
                 whitespace = Character.isWhitespace(oldCodepoint);
                 newCodePoint = oldCodepoint;
             }
             newCodePoints[outOffset++] = newCodePoint;
             index += Character.charCount(newCodePoint);
         }
         return new String(newCodePoints, 0, outOffset);
     }
 
     /**
      * Uncapitalizes all the whitespace separated words in a String. Only the first character of each word is changed.
      * <p>
      * Whitespace is defined by {@link Character#isWhitespace(char)}. A {@code null} input String returns {@code null}.
      * </p>
      *
      * <pre>
      * WordUtils.uncapitalize(null)        = null
      * WordUtils.uncapitalize("")          = ""
      * WordUtils.uncapitalize("I Am FINE") = "i am fINE"
      * </pre>
      *
      * @param str The String to uncapitalize, may be null.
      * @return A new uncapitalized String, or {@code null} if null String input.
      * @see #capitalize(String)
      */
     public static String uncapitalize(final String str) {
         return uncapitalize(str, null);
     }
 
     /**
      * Uncapitalizes all the whitespace separated words in a String. Only the first character of each word is changed.
      * <p>
      * The delimiters represent a set of characters understood to separate words. The first string character and the first non-delimiter character after a
      * delimiter will be uncapitalized.
      * </p>
      * <p>
      * Whitespace is defined by {@link Character#isWhitespace(char)}. A {@code null} input String returns {@code null}.
      * </p>
      *
      * <pre>
      * WordUtils.uncapitalize(null, *)            = null
      * WordUtils.uncapitalize("", *)              = ""
      * WordUtils.uncapitalize(*, null)            = *
      * WordUtils.uncapitalize(*, new char[0])     = *
      * WordUtils.uncapitalize("I AM.FINE", {'.'}) = "i AM.fINE"
      * WordUtils.uncapitalize("I am fine", new char[]{}) = "i am fine"
      * </pre>
      *
      * @param str        The String to uncapitalize, may be null.
      * @param delimiters set of characters to determine uncapitalization, null means whitespace.
      * @return uncapitalized String, or {@code null} if null String input.
      * @see #capitalize(String)
      */
     public static String uncapitalize(final String str, final char... delimiters) {
         return applyWordCaseTransform(str, delimiters, Character::toLowerCase);
     }
 
     /**
      * Wraps a single line of text, identifying words by {@code ' '}.
      *
      * <p>New lines will be separated by the system property line separator.
      * Very long words, such as URLs will <em>not</em> be wrapped.</p>
      *
      * <p>Leading spaces on a new line are stripped.
      * Trailing spaces are not stripped.</p>
      *
      * <table border="1">
      *  <caption>Examples</caption>
      *  <tr>
      *   <th>input</th>
      *   <th>wrapLength</th>
      *   <th>result</th>
      *  </tr>
      *  <tr>
      *   <td>null</td>
      *   <td>*</td>
      *   <td>null</td>
      *  </tr>
      *  <tr>
      *   <td>""</td>
      *   <td>*</td>
      *   <td>""</td>
      *  </tr>
      *  <tr>
      *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
      *   <td>20</td>
      *   <td>"Here is one line of\ntext that is going\nto be wrapped after\n20 columns."</td>
      *  </tr>
      *  <tr>
      *   <td>"Click here to jump to the commons website - https://commons.apache.org"</td>
      *   <td>20</td>
      *   <td>"Click here to jump\nto the commons\nwebsite -\nhttps://commons.apache.org"</td>
      *  </tr>
      *  <tr>
      *   <td>"Click here, https://commons.apache.org, to jump to the commons website"</td>
      *   <td>20</td>
      *   <td>"Click here,\nhttps://commons.apache.org,\nto jump to the\ncommons website"</td>
      *  </tr>
      * </table>
      *
      * (assuming that '\n' is the systems line separator)
      *
      * @param str  The String to be word wrapped, may be null.
      * @param wrapLength  The column to wrap the words at, less than 1 is treated as 1.
      * @return A line with newlines inserted, {@code null} if null input.
      */
     public static String wrap(final String str, final int wrapLength) {
         return wrap(str, wrapLength, null, false);
     }
 
     /**
      * Wraps a single line of text, identifying words by {@code ' '}.
      *
      * <p>Leading spaces on a new line are stripped.
      * Trailing spaces are not stripped.</p>
      *
      * <table border="1">
      *  <caption>Examples</caption>
      *  <tr>
      *   <th>input</th>
      *   <th>wrapLength</th>
      *   <th>newLineString</th>
      *   <th>wrapLongWords</th>
      *   <th>result</th>
      *  </tr>
      *  <tr>
      *   <td>null</td>
      *   <td>*</td>
      *   <td>*</td>
      *   <td>true/false</td>
      *   <td>null</td>
      *  </tr>
      *  <tr>
      *   <td>""</td>
      *   <td>*</td>
      *   <td>*</td>
      *   <td>true/false</td>
      *   <td>""</td>
      *  </tr>
      *  <tr>
      *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
      *   <td>20</td>
      *   <td>"\n"</td>
      *   <td>true/false</td>
      *   <td>"Here is one line of\ntext that is going\nto be wrapped after\n20 columns."</td>
      *  </tr>
      *  <tr>
      *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
      *   <td>20</td>
      *   <td>"&lt;br /&gt;"</td>
      *   <td>true/false</td>
      *   <td>"Here is one line of&lt;br /&gt;text that is going&lt;
      *   br /&gt;to be wrapped after&lt;br /&gt;20 columns."</td>
      *  </tr>
      *  <tr>
      *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
      *   <td>20</td>
      *   <td>null</td>
      *   <td>true/false</td>
      *   <td>"Here is one line of" + systemNewLine + "text that is going"
      *   + systemNewLine + "to be wrapped after" + systemNewLine + "20 columns."</td>
      *  </tr>
      *  <tr>
      *   <td>"Click here to jump to the commons website - https://commons.apache.org"</td>
      *   <td>20</td>
      *   <td>"\n"</td>
      *   <td>false</td>
      *   <td>"Click here to jump\nto the commons\nwebsite -\nhttps://commons.apache.org"</td>
      *  </tr>
      *  <tr>
      *   <td>"Click here to jump to the commons website - https://commons.apache.org"</td>
      *   <td>20</td>
      *   <td>"\n"</td>
      *   <td>true</td>
      *   <td>"Click here to jump\nto the commons\nwebsite -\nhttps://commons.apach\ne.org"</td>
      *  </tr>
      * </table>
      *
      * @param str  The String to be word wrapped, may be null.
      * @param wrapLength  The column to wrap the words at, less than 1 is treated as 1.
      * @param newLineStr  The string to insert for a new line, {@code null} uses the system property line separator.
      * @param wrapLongWords  true if long words (such as URLs) should be wrapped.
      * @return A line with newlines inserted, {@code null} if null input.
      */
     public static String wrap(final String str, final int wrapLength, final String newLineStr, final boolean wrapLongWords) {
         return wrap(str, wrapLength, newLineStr, wrapLongWords, " ");
     }
 
     /**
      * Wraps a single line of text, identifying words by {@code wrapOn}.
      *
      * <p>Leading spaces on a new line are stripped.
      * Trailing spaces are not stripped.</p>
      *
      * <table border="1">
      *  <caption>Examples</caption>
      *  <tr>
      *   <th>input</th>
      *   <th>wrapLength</th>
      *   <th>newLineString</th>
      *   <th>wrapLongWords</th>
      *   <th>wrapOn</th>
      *   <th>result</th>
      *  </tr>
      *  <tr>
      *   <td>null</td>
      *   <td>*</td>
      *   <td>*</td>
      *   <td>true/false</td>
      *   <td>*</td>
      *   <td>null</td>
      *  </tr>
      *  <tr>
      *   <td>""</td>
      *   <td>*</td>
      *   <td>*</td>
      *   <td>true/false</td>
      *   <td>*</td>
      *   <td>""</td>
      *  </tr>
      *  <tr>
      *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
      *   <td>20</td>
      *   <td>"\n"</td>
      *   <td>true/false</td>
      *   <td>" "</td>
      *   <td>"Here is one line of\ntext that is going\nto be wrapped after\n20 columns."</td>
      *  </tr>
      *  <tr>
      *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
      *   <td>20</td>
      *   <td>"&lt;br /&gt;"</td>
      *   <td>true/false</td>
      *   <td>" "</td>
      *   <td>"Here is one line of&lt;br /&gt;text that is going&lt;br /&gt;
      *   to be wrapped after&lt;br /&gt;20 columns."</td>
      *  </tr>
      *  <tr>
      *   <td>"Here is one line of text that is going to be wrapped after 20 columns."</td>
      *   <td>20</td>
      *   <td>null</td>
      *   <td>true/false</td>
      *   <td>" "</td>
      *   <td>"Here is one line of" + systemNewLine + "text that is going"
      *   + systemNewLine + "to be wrapped after" + systemNewLine + "20 columns."</td>
      *  </tr>
      *  <tr>
      *   <td>"Click here to jump to the commons website - https://commons.apache.org"</td>
      *   <td>20</td>
      *   <td>"\n"</td>
      *   <td>false</td>
      *   <td>" "</td>
      *   <td>"Click here to jump\nto the commons\nwebsite -\nhttps://commons.apache.org"</td>
      *  </tr>
      *  <tr>
      *   <td>"Click here to jump to the commons website - https://commons.apache.org"</td>
      *   <td>20</td>
      *   <td>"\n"</td>
      *   <td>true</td>
      *   <td>" "</td>
      *   <td>"Click here to jump\nto the commons\nwebsite -\nhttps://commons.apach\ne.org"</td>
      *  </tr>
      *  <tr>
      *   <td>"flammable/inflammable"</td>
      *   <td>20</td>
      *   <td>"\n"</td>
      *   <td>true</td>
      *   <td>"/"</td>
      *   <td>"flammable\ninflammable"</td>
      *  </tr>
      * </table>
      *
      * @param str  The String to be word wrapped, may be null.
      * @param wrapLength  The column to wrap the words at, less than 1 is treated as 1.
      * @param newLineStr  The string to insert for a new line, {@code null} uses the system property line separator.
      * @param wrapLongWords  true if long words (such as URLs) should be wrapped.
      * @param wrapOn Regex expression to be used as a breakable characters, if blank string is provided a space character will be used.
      * @return A line with newlines inserted, {@code null} if null input.
      */
     public static String wrap(final String str, int wrapLength, String newLineStr, final boolean wrapLongWords, String wrapOn) {
         if (str == null) {
             return null;
         }
         if (newLineStr == null) {
             newLineStr = System.lineSeparator();
         }
         if (wrapLength < 1) {
             wrapLength = 1;
         }
         if (StringUtils.isBlank(wrapOn)) {
             wrapOn = " ";
         }
         final Pattern patternToWrapOn = Pattern.compile(wrapOn);
         final int inputLineLength = str.length();
         int offset = 0;
         final StringBuilder wrappedLine = new StringBuilder(inputLineLength + 32);
         int matcherSize = -1;
         while (offset < inputLineLength) {
             int spaceToWrapAt = -1;
             Matcher matcher = patternToWrapOn
                     .matcher(str.substring(offset, Math.min((int) Math.min(Integer.MAX_VALUE, offset + wrapLength + 1L), inputLineLength)));
             if (matcher.find()) {
                 if (matcher.start() == 0) {
                     matcherSize = matcher.end();
                     if (matcherSize != 0) {
                         offset += matcher.end();
                         continue;
                     }
                     offset += 1;
                 }
                 spaceToWrapAt = matcher.start() + offset;
             }
             // only last line without leading spaces is left
             if (inputLineLength - offset <= wrapLength) {
                 break;
             }
             while (matcher.find()) {
                 spaceToWrapAt = matcher.start() + offset;
             }
             if (spaceToWrapAt >= offset) {
                 // normal case
                 wrappedLine.append(str, offset, spaceToWrapAt);
                 wrappedLine.append(newLineStr);
                 offset = spaceToWrapAt + 1;
             } else // really long word or URL
             if (wrapLongWords) {
                 if (matcherSize == 0) {
                     offset--;
                 }
                 // wrap really long word one line at a time, but keep a surrogate pair whole
                 int wrapAt = wrapLength + offset;
                 if (Character.isHighSurrogate(str.charAt(wrapAt - 1)) && Character.isLowSurrogate(str.charAt(wrapAt))) {
                     wrapAt++;
                 }
                 wrappedLine.append(str, offset, wrapAt);
                 wrappedLine.append(newLineStr);
                 offset = wrapAt;
                 matcherSize = -1;
             } else {
                 // do not wrap really long word, just extend beyond limit
                 matcher = patternToWrapOn.matcher(str.substring(offset + wrapLength));
                 if (matcher.find()) {
                     matcherSize = matcher.end() - matcher.start();
                     spaceToWrapAt = matcher.start() + offset + wrapLength;
                 }
                 if (spaceToWrapAt >= 0) {
                     if (matcherSize == 0 && offset != 0) {
                         offset--;
                     }
                     wrappedLine.append(str, offset, spaceToWrapAt);
                     wrappedLine.append(newLineStr);
                     offset = spaceToWrapAt + 1;
                 } else {
                     if (matcherSize == 0 && offset != 0) {
                         offset--;
                     }
                     wrappedLine.append(str, offset, str.length());
                     offset = inputLineLength;
                     matcherSize = -1;
                 }
             }
         }
         if (matcherSize == 0 && offset < inputLineLength) {
             offset--;
         }
         // Whatever is left in line is short enough to just pass through
         wrappedLine.append(str, offset, str.length());
         return wrappedLine.toString();
     }
 
     /**
      * {@code WordUtils} instances should NOT be constructed in standard programming. Instead, the class should be used as
      * {@code WordUtils.wrap("foo bar", 20);}.
      * <p>
      * This constructor is public to permit tools that require a JavaBean instance to operate.
      * </p>
      */
     public WordUtils() {
     }
  }