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</code> input gracefully. An exception will not be thrown for a
035 * <code>null</code> 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</code> instances should NOT be constructed in
044     * standard programming. Instead, the class should be used as
045     * <code>WordUtils.wrap("foo bar", 20);</code>.</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>' '</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 - http://commons.apache.org"</td>
089     *   <td>20</td>
090     *   <td>"Click here to jump\nto the commons\nwebsite -\nhttp://commons.apache.org"</td>
091     *  </tr>
092     *  <tr>
093     *   <td>"Click here, http://commons.apache.org, to jump to the commons website"</td>
094     *   <td>20</td>
095     *   <td>"Click here,\nhttp://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</code> 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>' '</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 - http://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 -\nhttp://commons.apache.org"</td>
167     *  </tr>
168     *  <tr>
169     *   <td>"Click here to jump to the commons website - http://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</code> 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</code> 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</code>.</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 - http://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 -\nhttp://commons.apache.org"</td>
256     *  </tr>
257     *  <tr>
258     *   <td>"Click here to jump to the commons website - http://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</code> 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</code> 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
305        while (offset < inputLineLength) {
306            int spaceToWrapAt = -1;
307            Matcher matcher = patternToWrapOn.matcher(str.substring(offset,
308                    Math.min((int) Math.min(Integer.MAX_VALUE, offset + wrapLength + 1L), inputLineLength)));
309            if (matcher.find()) {
310                if (matcher.start() == 0) {
311                    offset += matcher.end();
312                    continue;
313                }
314                spaceToWrapAt = matcher.start() + offset;
315            }
316
317            // only last line without leading spaces is left
318            if (inputLineLength - offset <= wrapLength) {
319                break;
320            }
321
322            while (matcher.find()) {
323                spaceToWrapAt = matcher.start() + offset;
324            }
325
326            if (spaceToWrapAt >= offset) {
327                // normal case
328                wrappedLine.append(str, offset, spaceToWrapAt);
329                wrappedLine.append(newLineStr);
330                offset = spaceToWrapAt + 1;
331
332            } else {
333                // really long word or URL
334                if (wrapLongWords) {
335                    // wrap really long word one line at a time
336                    wrappedLine.append(str, offset, wrapLength + offset);
337                    wrappedLine.append(newLineStr);
338                    offset += wrapLength;
339                } else {
340                    // do not wrap really long word, just extend beyond limit
341                    matcher = patternToWrapOn.matcher(str.substring(offset + wrapLength));
342                    if (matcher.find()) {
343                        spaceToWrapAt = matcher.start() + offset + wrapLength;
344                    }
345
346                    if (spaceToWrapAt >= 0) {
347                        wrappedLine.append(str, offset, spaceToWrapAt);
348                        wrappedLine.append(newLineStr);
349                        offset = spaceToWrapAt + 1;
350                    } else {
351                        wrappedLine.append(str, offset, str.length());
352                        offset = inputLineLength;
353                    }
354                }
355            }
356        }
357
358        // Whatever is left in line is short enough to just pass through
359        wrappedLine.append(str, offset, str.length());
360
361        return wrappedLine.toString();
362    }
363
364    // Capitalizing
365    //-----------------------------------------------------------------------
366    /**
367     * <p>Capitalizes all the whitespace separated words in a String.
368     * Only the first character of each word is changed. To convert the
369     * rest of each word to lowercase at the same time,
370     * use {@link #capitalizeFully(String)}.</p>
371     *
372     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
373     * A <code>null</code> input String returns <code>null</code>.
374     * Capitalization uses the Unicode title case, normally equivalent to
375     * upper case.</p>
376     *
377     * <pre>
378     * WordUtils.capitalize(null)        = null
379     * WordUtils.capitalize("")          = ""
380     * WordUtils.capitalize("i am FINE") = "I Am FINE"
381     * </pre>
382     *
383     * @param str  the String to capitalize, may be null
384     * @return capitalized String, <code>null</code> if null String input
385     * @see #uncapitalize(String)
386     * @see #capitalizeFully(String)
387     */
388    public static String capitalize(final String str) {
389        return capitalize(str, null);
390    }
391
392    /**
393     * <p>Capitalizes all the delimiter separated words in a String.
394     * Only the first character of each word is changed. To convert the
395     * rest of each word to lowercase at the same time,
396     * use {@link #capitalizeFully(String, char[])}.</p>
397     *
398     * <p>The delimiters represent a set of characters understood to separate words.
399     * The first string character and the first non-delimiter character after a
400     * delimiter will be capitalized. </p>
401     *
402     * <p>A <code>null</code> input String returns <code>null</code>.
403     * Capitalization uses the Unicode title case, normally equivalent to
404     * upper case.</p>
405     *
406     * <pre>
407     * WordUtils.capitalize(null, *)            = null
408     * WordUtils.capitalize("", *)              = ""
409     * WordUtils.capitalize(*, new char[0])     = *
410     * WordUtils.capitalize("i am fine", null)  = "I Am Fine"
411     * WordUtils.capitalize("i aM.fine", {'.'}) = "I aM.Fine"
412     * WordUtils.capitalize("i am fine", new char[]{}) = "I am fine"
413     * </pre>
414     *
415     * @param str  the String to capitalize, may be null
416     * @param delimiters  set of characters to determine capitalization, null means whitespace
417     * @return capitalized String, <code>null</code> if null String input
418     * @see #uncapitalize(String)
419     * @see #capitalizeFully(String)
420     */
421    public static String capitalize(final String str, final char... delimiters) {
422        if (StringUtils.isEmpty(str)) {
423            return str;
424        }
425        final Set<Integer> delimiterSet = generateDelimiterSet(delimiters);
426        final int strLen = str.length();
427        final int[] newCodePoints = new int[strLen];
428        int outOffset = 0;
429
430        boolean capitalizeNext = true;
431        for (int index = 0; index < strLen;) {
432            final int codePoint = str.codePointAt(index);
433
434            if (delimiterSet.contains(codePoint)) {
435                capitalizeNext = true;
436                newCodePoints[outOffset++] = codePoint;
437                index += Character.charCount(codePoint);
438            } else if (capitalizeNext) {
439                final int titleCaseCodePoint = Character.toTitleCase(codePoint);
440                newCodePoints[outOffset++] = titleCaseCodePoint;
441                index += Character.charCount(titleCaseCodePoint);
442                capitalizeNext = false;
443            } else {
444                newCodePoints[outOffset++] = codePoint;
445                index += Character.charCount(codePoint);
446            }
447        }
448        return new String(newCodePoints, 0, outOffset);
449    }
450
451    //-----------------------------------------------------------------------
452    /**
453     * <p>Converts all the whitespace separated words in a String into capitalized words,
454     * that is each word is made up of a titlecase character and then a series of
455     * lowercase characters.  </p>
456     *
457     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
458     * A <code>null</code> input String returns <code>null</code>.
459     * Capitalization uses the Unicode title case, normally equivalent to
460     * upper case.</p>
461     *
462     * <pre>
463     * WordUtils.capitalizeFully(null)        = null
464     * WordUtils.capitalizeFully("")          = ""
465     * WordUtils.capitalizeFully("i am FINE") = "I Am Fine"
466     * </pre>
467     *
468     * @param str  the String to capitalize, may be null
469     * @return capitalized String, <code>null</code> if null String input
470     */
471    public static String capitalizeFully(final String str) {
472        return capitalizeFully(str, null);
473    }
474
475    /**
476     * <p>Converts all the delimiter separated words in a String into capitalized words,
477     * that is each word is made up of a titlecase character and then a series of
478     * lowercase characters. </p>
479     *
480     * <p>The delimiters represent a set of characters understood to separate words.
481     * The first string character and the first non-delimiter character after a
482     * delimiter will be capitalized. </p>
483     *
484     * <p>A <code>null</code> input String returns <code>null</code>.
485     * Capitalization uses the Unicode title case, normally equivalent to
486     * upper case.</p>
487     *
488     * <pre>
489     * WordUtils.capitalizeFully(null, *)            = null
490     * WordUtils.capitalizeFully("", *)              = ""
491     * WordUtils.capitalizeFully(*, null)            = *
492     * WordUtils.capitalizeFully(*, new char[0])     = *
493     * WordUtils.capitalizeFully("i aM.fine", {'.'}) = "I am.Fine"
494     * </pre>
495     *
496     * @param str  the String to capitalize, may be null
497     * @param delimiters  set of characters to determine capitalization, null means whitespace
498     * @return capitalized String, <code>null</code> if null String input
499     */
500    public static String capitalizeFully(String str, final char... delimiters) {
501        if (StringUtils.isEmpty(str)) {
502            return str;
503        }
504        str = str.toLowerCase();
505        return capitalize(str, delimiters);
506    }
507
508    //-----------------------------------------------------------------------
509    /**
510     * <p>Uncapitalizes all the whitespace separated words in a String.
511     * Only the first character of each word is changed.</p>
512     *
513     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
514     * A <code>null</code> input String returns <code>null</code>.</p>
515     *
516     * <pre>
517     * WordUtils.uncapitalize(null)        = null
518     * WordUtils.uncapitalize("")          = ""
519     * WordUtils.uncapitalize("I Am FINE") = "i am fINE"
520     * </pre>
521     *
522     * @param str  the String to uncapitalize, may be null
523     * @return uncapitalized String, <code>null</code> if null String input
524     * @see #capitalize(String)
525     */
526    public static String uncapitalize(final String str) {
527        return uncapitalize(str, null);
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>The delimiters represent a set of characters understood to separate words.
535     * The first string character and the first non-delimiter character after a
536     * delimiter will be uncapitalized. </p>
537     *
538     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
539     * A <code>null</code> input String returns <code>null</code>.</p>
540     *
541     * <pre>
542     * WordUtils.uncapitalize(null, *)            = null
543     * WordUtils.uncapitalize("", *)              = ""
544     * WordUtils.uncapitalize(*, null)            = *
545     * WordUtils.uncapitalize(*, new char[0])     = *
546     * WordUtils.uncapitalize("I AM.FINE", {'.'}) = "i AM.fINE"
547     * WordUtils.uncapitalize("I am fine", new char[]{}) = "i am fine"
548     * </pre>
549     *
550     * @param str  the String to uncapitalize, may be null
551     * @param delimiters  set of characters to determine uncapitalization, null means whitespace
552     * @return uncapitalized String, <code>null</code> if null String input
553     * @see #capitalize(String)
554     */
555    public static String uncapitalize(final String str, final char... delimiters) {
556        if (StringUtils.isEmpty(str)) {
557            return str;
558        }
559        final Set<Integer> delimiterSet = generateDelimiterSet(delimiters);
560        final int strLen = str.length();
561        final int[] newCodePoints = new int[strLen];
562        int outOffset = 0;
563
564        boolean uncapitalizeNext = true;
565        for (int index = 0; index < strLen;) {
566            final int codePoint = str.codePointAt(index);
567
568            if (delimiterSet.contains(codePoint)) {
569                uncapitalizeNext = true;
570                newCodePoints[outOffset++] = codePoint;
571                index += Character.charCount(codePoint);
572            } else if (uncapitalizeNext) {
573                final int titleCaseCodePoint = Character.toLowerCase(codePoint);
574                newCodePoints[outOffset++] = titleCaseCodePoint;
575                index += Character.charCount(titleCaseCodePoint);
576                uncapitalizeNext = false;
577            } else {
578                newCodePoints[outOffset++] = codePoint;
579                index += Character.charCount(codePoint);
580            }
581        }
582        return new String(newCodePoints, 0, outOffset);
583    }
584
585    //-----------------------------------------------------------------------
586    /**
587     * <p>Swaps the case of a String using a word based algorithm.</p>
588     *
589     * <ul>
590     *  <li>Upper case character converts to Lower case</li>
591     *  <li>Title case character converts to Lower case</li>
592     *  <li>Lower case character after Whitespace or at start converts to Title case</li>
593     *  <li>Other Lower case character converts to Upper case</li>
594     * </ul>
595     *
596     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
597     * A <code>null</code> input String returns <code>null</code>.</p>
598     *
599     * <pre>
600     * StringUtils.swapCase(null)                 = null
601     * StringUtils.swapCase("")                   = ""
602     * StringUtils.swapCase("The dog has a BONE") = "tHE DOG HAS A bone"
603     * </pre>
604     *
605     * @param str  the String to swap case, may be null
606     * @return the changed String, <code>null</code> if null String input
607     */
608    public static String swapCase(final String str) {
609        if (StringUtils.isEmpty(str)) {
610            return str;
611        }
612        final int strLen = str.length();
613        final int[] newCodePoints = new int[strLen];
614        int outOffset = 0;
615        boolean whitespace = true;
616        for (int index = 0; index < strLen;) {
617            final int oldCodepoint = str.codePointAt(index);
618            final int newCodePoint;
619            if (Character.isUpperCase(oldCodepoint) || Character.isTitleCase(oldCodepoint)) {
620                newCodePoint = Character.toLowerCase(oldCodepoint);
621                whitespace = false;
622            } else if (Character.isLowerCase(oldCodepoint)) {
623                if (whitespace) {
624                    newCodePoint = Character.toTitleCase(oldCodepoint);
625                    whitespace = false;
626                } else {
627                    newCodePoint = Character.toUpperCase(oldCodepoint);
628                }
629            } else {
630                whitespace = Character.isWhitespace(oldCodepoint);
631                newCodePoint = oldCodepoint;
632            }
633            newCodePoints[outOffset++] = newCodePoint;
634            index += Character.charCount(newCodePoint);
635        }
636        return new String(newCodePoints, 0, outOffset);
637    }
638
639    //-----------------------------------------------------------------------
640    /**
641     * <p>Extracts the initial characters from each word in the String.</p>
642     *
643     * <p>All first characters after whitespace are returned as a new string.
644     * Their case is not changed.</p>
645     *
646     * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.
647     * A <code>null</code> input String returns <code>null</code>.</p>
648     *
649     * <pre>
650     * WordUtils.initials(null)             = null
651     * WordUtils.initials("")               = ""
652     * WordUtils.initials("Ben John Lee")   = "BJL"
653     * WordUtils.initials("Ben J.Lee")      = "BJ"
654     * </pre>
655     *
656     * @param str  the String to get initials from, may be null
657     * @return String of initial letters, <code>null</code> if null String input
658     * @see #initials(String,char[])
659     */
660    public static String initials(final String str) {
661        return initials(str, null);
662    }
663
664    /**
665     * <p>Extracts the initial characters from each word in the String.</p>
666     *
667     * <p>All first characters after the defined delimiters are returned as a new string.
668     * Their case is not changed.</p>
669     *
670     * <p>If the delimiters array is null, then Whitespace is used.
671     * Whitespace is defined by {@link Character#isWhitespace(char)}.
672     * A <code>null</code> input String returns <code>null</code>.
673     * An empty delimiter array returns an empty String.</p>
674     *
675     * <pre>
676     * WordUtils.initials(null, *)                = null
677     * WordUtils.initials("", *)                  = ""
678     * WordUtils.initials("Ben John Lee", null)   = "BJL"
679     * WordUtils.initials("Ben J.Lee", null)      = "BJ"
680     * WordUtils.initials("Ben J.Lee", [' ','.']) = "BJL"
681     * WordUtils.initials(*, new char[0])         = ""
682     * </pre>
683     *
684     * @param str  the String to get initials from, may be null
685     * @param delimiters  set of characters to determine words, null means whitespace
686     * @return String of initial characters, <code>null</code> if null String input
687     * @see #initials(String)
688     */
689    public static String initials(final String str, final char... delimiters) {
690        if (StringUtils.isEmpty(str)) {
691            return str;
692        }
693        if (delimiters != null && delimiters.length == 0) {
694            return "";
695        }
696        final Set<Integer> delimiterSet = generateDelimiterSet(delimiters);
697        final int strLen = str.length();
698        final int[] newCodePoints = new int[strLen / 2 + 1];
699        int count = 0;
700        boolean lastWasGap = true;
701        for (int i = 0; i < strLen;) {
702            final int codePoint = str.codePointAt(i);
703
704            if (delimiterSet.contains(codePoint) || (delimiters == null && Character.isWhitespace(codePoint))) {
705                lastWasGap = true;
706            } else if (lastWasGap) {
707                newCodePoints[count++] = codePoint;
708                lastWasGap = false;
709            }
710
711            i += Character.charCount(codePoint);
712        }
713        return new String(newCodePoints, 0, count);
714    }
715
716    //-----------------------------------------------------------------------
717    /**
718     * <p>Checks if the String contains all words in the given array.</p>
719     *
720     * <p>
721     * A {@code null} String will return {@code false}. A {@code null}, zero
722     * length search array or if one element of array is null will return {@code false}.
723     * </p>
724     *
725     * <pre>
726     * WordUtils.containsAllWords(null, *)            = false
727     * WordUtils.containsAllWords("", *)              = false
728     * WordUtils.containsAllWords(*, null)            = false
729     * WordUtils.containsAllWords(*, [])              = false
730     * WordUtils.containsAllWords("abcd", "ab", "cd") = false
731     * WordUtils.containsAllWords("abc def", "def", "abc") = true
732     * </pre>
733     *
734     * @param word The CharSequence to check, may be null
735     * @param words The array of String words to search for, may be null
736     * @return {@code true} if all search words are found, {@code false} otherwise
737     */
738    public static boolean containsAllWords(final CharSequence word, final CharSequence... words) {
739        if (StringUtils.isEmpty(word) || ArrayUtils.isEmpty(words)) {
740            return false;
741        }
742        for (final CharSequence w : words) {
743            if (StringUtils.isBlank(w)) {
744                return false;
745            }
746            final Pattern p = Pattern.compile(".*\\b" + w + "\\b.*");
747            if (!p.matcher(word).matches()) {
748                return false;
749            }
750        }
751        return true;
752    }
753
754    //-----------------------------------------------------------------------
755    /**
756     * Is the character a delimiter.
757     *
758     * @param ch the character to check
759     * @param delimiters the delimiters
760     * @return true if it is a delimiter
761     * @deprecated as of 1.2 and will be removed in 2.0
762     */
763    @Deprecated
764    public static boolean isDelimiter(final char ch, final char[] delimiters) {
765        if (delimiters == null) {
766            return Character.isWhitespace(ch);
767        }
768        for (final char delimiter : delimiters) {
769            if (ch == delimiter) {
770                return true;
771            }
772        }
773        return false;
774    }
775
776  //-----------------------------------------------------------------------
777    /**
778     * Is the codePoint a delimiter.
779     *
780     * @param codePoint the codePint to check
781     * @param delimiters the delimiters
782     * @return true if it is a delimiter
783     * @deprecated as of 1.2 and will be removed in 2.0
784     */
785    @Deprecated
786    public static boolean isDelimiter(final int codePoint, final char[] delimiters) {
787        if (delimiters == null) {
788            return Character.isWhitespace(codePoint);
789        }
790        for (int index = 0; index < delimiters.length; index++) {
791            final int delimiterCodePoint = Character.codePointAt(delimiters, index);
792            if (delimiterCodePoint == codePoint) {
793                return true;
794            }
795        }
796        return false;
797    }
798
799    //-----------------------------------------------------------------------
800    /**
801     * Abbreviates the words nicely.
802     *
803     * This method searches for the first space after the lower limit and abbreviates
804     * the String there. It will also append any String passed as a parameter
805     * to the end of the String. The upper limit can be specified to forcibly
806     * abbreviate a String.
807     *
808     * @param str         the string to be abbreviated. If null is passed, null is returned.
809     *                    If the empty String is passed, the empty string is returned.
810     * @param lower       the lower limit.
811     * @param upper       the upper limit; specify -1 if no limit is desired.
812     *                    If the upper limit is lower than the lower limit, it will be
813     *                    adjusted to be the same as the lower limit.
814     * @param appendToEnd String to be appended to the end of the abbreviated string.
815     *                    This is appended ONLY if the string was indeed abbreviated.
816     *                    The append does not count towards the lower or upper limits.
817     * @return the abbreviated String.
818     *
819     * <pre>
820     * WordUtils.abbreviate("Now is the time for all good men", 0, 40, null));     = "Now"
821     * WordUtils.abbreviate("Now is the time for all good men", 10, 40, null));    = "Now is the"
822     * WordUtils.abbreviate("Now is the time for all good men", 20, 40, null));    = "Now is the time for all"
823     * WordUtils.abbreviate("Now is the time for all good men", 0, 40, ""));       = "Now"
824     * WordUtils.abbreviate("Now is the time for all good men", 10, 40, ""));      = "Now is the"
825     * WordUtils.abbreviate("Now is the time for all good men", 20, 40, ""));      = "Now is the time for all"
826     * WordUtils.abbreviate("Now is the time for all good men", 0, 40, " ..."));   = "Now ..."
827     * WordUtils.abbreviate("Now is the time for all good men", 10, 40, " ..."));  = "Now is the ..."
828     * WordUtils.abbreviate("Now is the time for all good men", 20, 40, " ..."));  = "Now is the time for all ..."
829     * WordUtils.abbreviate("Now is the time for all good men", 0, -1, ""));       = "Now"
830     * WordUtils.abbreviate("Now is the time for all good men", 10, -1, ""));      = "Now is the"
831     * WordUtils.abbreviate("Now is the time for all good men", 20, -1, ""));      = "Now is the time for all"
832     * WordUtils.abbreviate("Now is the time for all good men", 50, -1, ""));      = "Now is the time for all good men"
833     * WordUtils.abbreviate("Now is the time for all good men", 1000, -1, ""));    = "Now is the time for all good men"
834     * WordUtils.abbreviate("Now is the time for all good men", 9, -10, null));    = IllegalArgumentException
835     * WordUtils.abbreviate("Now is the time for all good men", 10, 5, null));     = IllegalArgumentException
836     * </pre>
837     */
838    public static String abbreviate(final String str, int lower, int upper, final String appendToEnd) {
839        Validate.isTrue(upper >= -1, "upper value cannot be less than -1");
840        Validate.isTrue(upper >= lower || upper == -1, "upper value is less than lower value");
841
842        if (StringUtils.isEmpty(str)) {
843            return str;
844        }
845
846        // if the lower value is greater than the length of the string,
847        // set to the length of the string
848        if (lower > str.length()) {
849            lower = str.length();
850        }
851
852        // if the upper value is -1 (i.e. no limit) or is greater
853        // than the length of the string, set to the length of the string
854        if (upper == -1 || upper > str.length()) {
855            upper = str.length();
856        }
857
858        final StringBuilder result = new StringBuilder();
859        final int index = StringUtils.indexOf(str, " ", lower);
860        if (index == -1) {
861            result.append(str, 0, upper);
862            // only if abbreviation has occured do we append the appendToEnd value
863            if (upper != str.length()) {
864                result.append(StringUtils.defaultString(appendToEnd));
865            }
866        } else if (index > upper) {
867            result.append(str, 0, upper);
868            result.append(StringUtils.defaultString(appendToEnd));
869        } else {
870            result.append(str, 0, index);
871            result.append(StringUtils.defaultString(appendToEnd));
872        }
873
874        return result.toString();
875    }
876
877    // -----------------------------------------------------------------------
878    /**
879     * <p>
880     * Converts an array of delimiters to a hash set of code points. Code point of space(32) is added as the default
881     * value if delimiters is null. The generated hash set provides O(1) lookup time.
882     * </p>
883     *
884     * @param delimiters set of characters to determine capitalization, null means whitespace
885     * @return Set<Integer>
886     */
887    private static Set<Integer> generateDelimiterSet(final char[] delimiters) {
888        final Set<Integer> delimiterHashSet = new HashSet<>();
889        if (delimiters == null || delimiters.length == 0) {
890            if (delimiters == null) {
891                delimiterHashSet.add(Character.codePointAt(new char[] {' '}, 0));
892            }
893
894            return delimiterHashSet;
895        }
896
897        for (int index = 0; index < delimiters.length; index++) {
898            delimiterHashSet.add(Character.codePointAt(delimiters, index));
899        }
900        return delimiterHashSet;
901    }
902 }