code: /*
   * 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
   * 
   *      http://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.lang;
  
  /**
   * <p>Operations on Strings that contain words.</p>
   * 
   * <p>This class tries to handle <code>null</code> input gracefully.
   * An exception will not be thrown for a <code>null</code> input.
   * Each method documents its behaviour in more detail.</p>
   * 
   * @author Apache Jakarta Velocity
   * @author Stephen Colebourne
   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
   * @author Gary Gregory
   * @since 2.0
   * @version $Id: WordUtils.java 471626 2006-11-06 04:02:09Z bayard $
   */
  public class WordUtils {
  
      /**
       * <p><code>WordUtils</code> instances should NOT be constructed in
       * standard programming. Instead, the class should be used as
       * <code>WordUtils.wrap("foo bar", 20);</code>.</p>
       *
       * <p>This constructor is public to permit tools that require a JavaBean
       * instance to operate.</p>
       */
      public WordUtils() {
        super();
      }
  
      // Wrapping
      //--------------------------------------------------------------------------
  //    /**
  //     * <p>Wraps a block of text to a specified line length using '\n' as
  //     * a newline.</p>
  //     *
  //     * <p>This method takes a block of text, which might have long lines in it
  //     * and wraps the long lines based on the supplied lineLength parameter.</p>
  //     * 
  //     * <p>If a single word is longer than the line length (eg. a URL), it will
  //     * not be broken, and will display beyond the expected width.</p>
  //     * 
  //     * <p>If there are tabs in inString, you are going to get results that are
  //     * a bit strange. Tabs are a single character but are displayed as 4 or 8
  //     * spaces. Remove the tabs.</p>
  //     *
  //     * @param str  text which is in need of word-wrapping, may be null
  //     * @param lineLength  the column to wrap the words at
  //     * @return the text with all the long lines word-wrapped
  //     *  <code>null</code> if null string input
  //     */
  //    public static String wrapText(String str, int lineLength) {
  //        return wrap(str, null, lineLength);
  //    }
      
  //    /**
  //     * <p>Wraps a block of text to a specified line length.</p>
  //     *
  //     * <p>This method takes a block of text, which might have long lines in it
  //     * and wraps the long lines based on the supplied lineLength parameter.</p>
  //     * 
  //     * <p>If a single word is longer than the wrapColumn (eg. a URL), it will
  //     * not be broken, and will display beyond the expected width.</p>
  //     * 
  //     * <p>If there are tabs in inString, you are going to get results that are
  //     * a bit strange. Tabs are a single character but are displayed as 4 or 8
  //     * spaces. Remove the tabs.</p>
  //     *
  //     * @param str  text which is in need of word-wrapping, may be null
  //     * @param newLineChars  the characters that define a newline, null treated as \n
  //     * @param lineLength  the column to wrap the words at
  //     * @return the text with all the long lines word-wrapped
  //     *  <code>null</code> if null string input
  //     */
  //    public static String wrapText(String str, String newLineChars, int lineLength) {
  //        if (str == null) {
  //            return null;
  //        }
  //        if (newLineChars == null) {
  //            newLineChars = "\n";
  //        }
  //        StringTokenizer lineTokenizer = new StringTokenizer(str, newLineChars, true);
  //        StringBuffer stringBuffer = new StringBuffer();
  //
  //        while (lineTokenizer.hasMoreTokens()) {
  //            try {
  //                String nextLine = lineTokenizer.nextToken();
  //
  //                if (nextLine.length() > lineLength) {
  //                    // This line is long enough to be wrapped.
  //                    nextLine = wrapLine(nextLine, null, lineLength, false);
  //                }
  //
  //                stringBuffer.append(nextLine);
  //
  //            } catch (NoSuchElementException nsee) {
  //                // thrown by nextToken(), but I don't know why it would
  //                break;
  //            }
  //        }
  //
  //        return stringBuffer.toString();
  //    }
  
      // Wrapping
      //-----------------------------------------------------------------------
      /**
       * <p>Wraps a single line of text, identifying words by <code>' '</code>.</p>
       * 
       * <p>New lines will be separated by the system property line separator.
       * Very long words, such as URLs will <i>not</i> be wrapped.</p>
       * 
       * <p>Leading spaces on a new line are stripped.
       * Trailing spaces are not stripped.</p>
       *
       * <pre>
       * WordUtils.wrap(null, *) = null
       * WordUtils.wrap("", *) = ""
       * </pre>
       *
       * @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</code> if null input
       */
      public static String wrap(String str, int wrapLength) {
          return wrap(str, wrapLength, null, false);
      }
      
      /**
       * <p>Wraps a single line of text, identifying words by <code>' '</code>.</p>
       * 
       * <p>Leading spaces on a new line are stripped.
       * Trailing spaces are not stripped.</p>
       * 
       * <pre>
       * WordUtils.wrap(null, *, *, *) = null
       * WordUtils.wrap("", *, *, *) = ""
       * </pre>
       *
       * @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</code> 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</code> if null input
       */
      public static String wrap(String str, int wrapLength, String newLineStr, boolean wrapLongWords) {
          if (str == null) {
              return null;
          }
          if (newLineStr == null) {
              newLineStr = SystemUtils.LINE_SEPARATOR;
          }
          if (wrapLength < 1) {
              wrapLength = 1;
          }
          int inputLineLength = str.length();
          int offset = 0;
          StringBuffer wrappedLine = new StringBuffer(inputLineLength + 32);
          
          while ((inputLineLength - offset) > wrapLength) {
              if (str.charAt(offset) == ' ') {
                  offset++;
                  continue;
              }
              int spaceToWrapAt = str.lastIndexOf(' ', wrapLength + offset);
  
              if (spaceToWrapAt >= offset) {
                  // normal case
                  wrappedLine.append(str.substring(offset, spaceToWrapAt));
                  wrappedLine.append(newLineStr);
                  offset = spaceToWrapAt + 1;
                  
              } else {
                  // really long word or URL
                  if (wrapLongWords) {
                      // wrap really long word one line at a time
                      wrappedLine.append(str.substring(offset, wrapLength + offset));
                      wrappedLine.append(newLineStr);
                      offset += wrapLength;
                  } else {
                      // do not wrap really long word, just extend beyond limit
                      spaceToWrapAt = str.indexOf(' ', wrapLength + offset);
                      if (spaceToWrapAt >= 0) {
                          wrappedLine.append(str.substring(offset, spaceToWrapAt));
                          wrappedLine.append(newLineStr);
                          offset = spaceToWrapAt + 1;
                      } else {
                          wrappedLine.append(str.substring(offset));
                          offset = inputLineLength;
                      }
                  }
              }
          }
  
          // Whatever is left in line is short enough to just pass through
          wrappedLine.append(str.substring(offset));
  
          return wrappedLine.toString();
      }
  
      // Capitalizing
      //-----------------------------------------------------------------------
      /**
       * <p>Capitalizes all the whitespace separated words in a String.
       * Only the first letter of each word is changed. To convert the 
       * rest of each word to lowercase at the same time, 
       * use {@link #capitalizeFully(String)}.</p>
       *
       * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
       * A <code>null</code> input String returns <code>null</code>.
       * 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 capitalized String, <code>null</code> if null String input
       * @see #uncapitalize(String)
       * @see #capitalizeFully(String)
       */
      public static String capitalize(String str) {
          return capitalize(str, null);
      }
  
      /**
       * <p>Capitalizes all the delimiter separated words in a String.
       * Only the first letter of each word is changed. To convert the 
       * rest of each word to lowercase at the same time, 
       * use {@link #capitalizeFully(String, char[])}.</p>
       *
       * <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</code> input String returns <code>null</code>.
       * 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"
       * </pre>
       * 
       * @param str  the String to capitalize, may be null
       * @param delimiters  set of characters to determine capitalization, null means whitespace
       * @return capitalized String, <code>null</code> if null String input
       * @see #uncapitalize(String)
       * @see #capitalizeFully(String)
       * @since 2.1
       */
      public static String capitalize(String str, char[] delimiters) {
          int delimLen = (delimiters == null ? -1 : delimiters.length);
          if (str == null || str.length() == 0 || delimLen == 0) {
              return str;
          }
          int strLen = str.length();
          StringBuffer buffer = new StringBuffer(strLen);
          boolean capitalizeNext = true;
          for (int i = 0; i < strLen; i++) {
              char ch = str.charAt(i);
  
              if (isDelimiter(ch, delimiters)) {
                  buffer.append(ch);
                  capitalizeNext = true;
              } else if (capitalizeNext) {
                  buffer.append(Character.toTitleCase(ch));
                  capitalizeNext = false;
              } else {
                  buffer.append(ch);
              }
          }
          return buffer.toString();
      }
  
      //-----------------------------------------------------------------------
      /**
       * <p>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>
       *
       * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
       * A <code>null</code> input String returns <code>null</code>.
       * 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 capitalized String, <code>null</code> if null String input
       */
      public static String capitalizeFully(String str) {
          return capitalizeFully(str, null);
      }
  
      /**
       * <p>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>
       *
       * <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</code> input String returns <code>null</code>.
       * 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  set of characters to determine capitalization, null means whitespace
       * @return capitalized String, <code>null</code> if null String input
       * @since 2.1
       */
      public static String capitalizeFully(String str, char[] delimiters) {
          int delimLen = (delimiters == null ? -1 : delimiters.length);
          if (str == null || str.length() == 0 || delimLen == 0) {
              return str;
          }
          str = str.toLowerCase();
          return capitalize(str, delimiters);
      }
  
      //-----------------------------------------------------------------------
      /**
       * <p>Uncapitalizes all the whitespace separated words in a String.
       * Only the first letter of each word is changed.</p>
       *
       * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
       * A <code>null</code> input String returns <code>null</code>.</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 uncapitalized String, <code>null</code> if null String input
       * @see #capitalize(String)
       */
      public static String uncapitalize(String str) {
          return uncapitalize(str, null);
      }
  
      /**
       * <p>Uncapitalizes all the whitespace separated words in a String.
       * Only the first letter of each word is changed.</p>
       *
       * <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</code> input String returns <code>null</code>.</p>
       *
       * <pre>
       * WordUtils.uncapitalize(null, *)            = null
       * WordUtils.uncapitalize("", *)              = ""
       * WordUtils.uncapitalize(*, null)            = *
       * WordUtils.uncapitalize(*, new char[0])     = *
       * WordUtils.uncapitalize("I AM.FINE", {'.'}) = "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, <code>null</code> if null String input
       * @see #capitalize(String)
       * @since 2.1
       */
      public static String uncapitalize(String str, char[] delimiters) {
          int delimLen = (delimiters == null ? -1 : delimiters.length);
          if (str == null || str.length() == 0 || delimLen == 0) {
              return str;
          }
          int strLen = str.length();
          StringBuffer buffer = new StringBuffer(strLen);
          boolean uncapitalizeNext = true;
          for (int i = 0; i < strLen; i++) {
              char ch = str.charAt(i);
  
              if (isDelimiter(ch, delimiters)) {
                  buffer.append(ch);
                  uncapitalizeNext = true;
              } else if (uncapitalizeNext) {
                  buffer.append(Character.toLowerCase(ch));
                  uncapitalizeNext = false;
              } else {
                  buffer.append(ch);
              }
          }
          return buffer.toString();
      }
  
      //-----------------------------------------------------------------------
      /**
       * <p>Swaps the case of a String using a word based algorithm.</p>
       * 
       * <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</code> input String returns <code>null</code>.</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, <code>null</code> if null String input
       */
      public static String swapCase(String str) {
          int strLen;
          if (str == null || (strLen = str.length()) == 0) {
              return str;
          }
          StringBuffer buffer = new StringBuffer(strLen);
  
          boolean whitespace = true;
          char ch = 0;
          char tmp = 0;
  
          for (int i = 0; i < strLen; i++) {
              ch = str.charAt(i);
              if (Character.isUpperCase(ch)) {
                  tmp = Character.toLowerCase(ch);
              } else if (Character.isTitleCase(ch)) {
                  tmp = Character.toLowerCase(ch);
              } else if (Character.isLowerCase(ch)) {
                  if (whitespace) {
                      tmp = Character.toTitleCase(ch);
                  } else {
                      tmp = Character.toUpperCase(ch);
                  }
              } else {
                  tmp = ch;
              }
              buffer.append(tmp);
              whitespace = Character.isWhitespace(ch);
          }
          return buffer.toString();
      }
  
      //-----------------------------------------------------------------------
      /**
       * <p>Extracts the initial letters from each word in the String.</p>
       * 
       * <p>The first letter of the string and all first letters 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</code> input String returns <code>null</code>.</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 String of initial letters, <code>null</code> if null String input
       * @see #initials(String,char[])
       * @since 2.2
       */
      public static String initials(String str) {
          return initials(str, null);
      }
  
      /**
       * <p>Extracts the initial letters from each word in the String.</p>
       * 
       * <p>The first letter of the string and all first letters 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</code> input String returns <code>null</code>.
       * 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  set of characters to determine words, null means whitespace
       * @return String of initial letters, <code>null</code> if null String input
       * @see #initials(String)
       * @since 2.2
       */
      public static String initials(String str, char[] delimiters) {
          if (str == null || str.length() == 0) {
              return str;
          }
          if (delimiters != null && delimiters.length == 0) {
              return "";
          }
          int strLen = str.length();
          char[] buf = new char[strLen / 2 + 1];
          int count = 0;
          boolean lastWasGap = true;
          for (int i = 0; i < strLen; i++) {
              char ch = str.charAt(i);
  
              if (isDelimiter(ch, delimiters)) {
                  lastWasGap = true;
              } else if (lastWasGap) {
                  buf[count++] = ch;
                  lastWasGap = false;
              } else {
                  // ignore ch
              }
          }
          return new String(buf, 0, count);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Is the character a delimiter.
       *
       * @param ch  the character to check
       * @param delimiters  the delimiters
       * @return true if it is a delimiter
       */
      private static boolean isDelimiter(char ch, char[] delimiters) {
          if (delimiters == null) {
              return Character.isWhitespace(ch);
          }
          for (int i = 0, isize = delimiters.length; i < isize; i++) {
              if (ch == delimiters[i]) {
                  return true;
              }
          }
          return false;
      }
  
  }
  