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