001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019 package org.apache.hadoop.util;
020
021 import java.io.PrintWriter;
022 import java.io.StringWriter;
023 import java.net.URI;
024 import java.net.URISyntaxException;
025 import java.text.DateFormat;
026 import java.util.ArrayList;
027 import java.util.Arrays;
028 import java.util.Collection;
029 import java.util.Date;
030 import java.util.Iterator;
031 import java.util.List;
032 import java.util.Locale;
033 import java.util.Map;
034 import java.util.StringTokenizer;
035 import java.util.regex.Matcher;
036 import java.util.regex.Pattern;
037
038 import org.apache.commons.lang.SystemUtils;
039 import org.apache.hadoop.classification.InterfaceAudience;
040 import org.apache.hadoop.classification.InterfaceStability;
041 import org.apache.hadoop.fs.Path;
042 import org.apache.hadoop.net.NetUtils;
043
044 import com.google.common.net.InetAddresses;
045
046 /**
047 * General string utils
048 */
049 @InterfaceAudience.Private
050 @InterfaceStability.Unstable
051 public class StringUtils {
052
053 /**
054 * Priority of the StringUtils shutdown hook.
055 */
056 public static final int SHUTDOWN_HOOK_PRIORITY = 0;
057
058 /**
059 * Shell environment variables: $ followed by one letter or _ followed by
060 * multiple letters, numbers, or underscores. The group captures the
061 * environment variable name without the leading $.
062 */
063 public static final Pattern SHELL_ENV_VAR_PATTERN =
064 Pattern.compile("\\$([A-Za-z_]{1}[A-Za-z0-9_]*)");
065
066 /**
067 * Windows environment variables: surrounded by %. The group captures the
068 * environment variable name without the leading and trailing %.
069 */
070 public static final Pattern WIN_ENV_VAR_PATTERN = Pattern.compile("%(.*?)%");
071
072 /**
073 * Regular expression that matches and captures environment variable names
074 * according to platform-specific rules.
075 */
076 public static final Pattern ENV_VAR_PATTERN = Shell.WINDOWS ?
077 WIN_ENV_VAR_PATTERN : SHELL_ENV_VAR_PATTERN;
078
079 /**
080 * Make a string representation of the exception.
081 * @param e The exception to stringify
082 * @return A string with exception name and call stack.
083 */
084 public static String stringifyException(Throwable e) {
085 StringWriter stm = new StringWriter();
086 PrintWriter wrt = new PrintWriter(stm);
087 e.printStackTrace(wrt);
088 wrt.close();
089 return stm.toString();
090 }
091
092 /**
093 * Given a full hostname, return the word upto the first dot.
094 * @param fullHostname the full hostname
095 * @return the hostname to the first dot
096 */
097 public static String simpleHostname(String fullHostname) {
098 if (InetAddresses.isInetAddress(fullHostname)) {
099 return fullHostname;
100 }
101 int offset = fullHostname.indexOf('.');
102 if (offset != -1) {
103 return fullHostname.substring(0, offset);
104 }
105 return fullHostname;
106 }
107
108 /**
109 * Given an integer, return a string that is in an approximate, but human
110 * readable format.
111 * @param number the number to format
112 * @return a human readable form of the integer
113 *
114 * @deprecated use {@link TraditionalBinaryPrefix#long2String(long, String, int)}.
115 */
116 @Deprecated
117 public static String humanReadableInt(long number) {
118 return TraditionalBinaryPrefix.long2String(number, "", 1);
119 }
120
121 /** The same as String.format(Locale.ENGLISH, format, objects). */
122 public static String format(final String format, final Object... objects) {
123 return String.format(Locale.ENGLISH, format, objects);
124 }
125
126 /**
127 * Format a percentage for presentation to the user.
128 * @param fraction the percentage as a fraction, e.g. 0.1 = 10%
129 * @param decimalPlaces the number of decimal places
130 * @return a string representation of the percentage
131 */
132 public static String formatPercent(double fraction, int decimalPlaces) {
133 return format("%." + decimalPlaces + "f%%", fraction*100);
134 }
135
136 /**
137 * Given an array of strings, return a comma-separated list of its elements.
138 * @param strs Array of strings
139 * @return Empty string if strs.length is 0, comma separated list of strings
140 * otherwise
141 */
142
143 public static String arrayToString(String[] strs) {
144 if (strs.length == 0) { return ""; }
145 StringBuilder sbuf = new StringBuilder();
146 sbuf.append(strs[0]);
147 for (int idx = 1; idx < strs.length; idx++) {
148 sbuf.append(",");
149 sbuf.append(strs[idx]);
150 }
151 return sbuf.toString();
152 }
153
154 /**
155 * Given an array of bytes it will convert the bytes to a hex string
156 * representation of the bytes
157 * @param bytes
158 * @param start start index, inclusively
159 * @param end end index, exclusively
160 * @return hex string representation of the byte array
161 */
162 public static String byteToHexString(byte[] bytes, int start, int end) {
163 if (bytes == null) {
164 throw new IllegalArgumentException("bytes == null");
165 }
166 StringBuilder s = new StringBuilder();
167 for(int i = start; i < end; i++) {
168 s.append(format("%02x", bytes[i]));
169 }
170 return s.toString();
171 }
172
173 /** Same as byteToHexString(bytes, 0, bytes.length). */
174 public static String byteToHexString(byte bytes[]) {
175 return byteToHexString(bytes, 0, bytes.length);
176 }
177
178 /**
179 * Given a hexstring this will return the byte array corresponding to the
180 * string
181 * @param hex the hex String array
182 * @return a byte array that is a hex string representation of the given
183 * string. The size of the byte array is therefore hex.length/2
184 */
185 public static byte[] hexStringToByte(String hex) {
186 byte[] bts = new byte[hex.length() / 2];
187 for (int i = 0; i < bts.length; i++) {
188 bts[i] = (byte) Integer.parseInt(hex.substring(2 * i, 2 * i + 2), 16);
189 }
190 return bts;
191 }
192 /**
193 *
194 * @param uris
195 */
196 public static String uriToString(URI[] uris){
197 if (uris == null) {
198 return null;
199 }
200 StringBuilder ret = new StringBuilder(uris[0].toString());
201 for(int i = 1; i < uris.length;i++){
202 ret.append(",");
203 ret.append(uris[i].toString());
204 }
205 return ret.toString();
206 }
207
208 /**
209 * @param str
210 * The string array to be parsed into an URI array.
211 * @return <tt>null</tt> if str is <tt>null</tt>, else the URI array
212 * equivalent to str.
213 * @throws IllegalArgumentException
214 * If any string in str violates RFC 2396.
215 */
216 public static URI[] stringToURI(String[] str){
217 if (str == null)
218 return null;
219 URI[] uris = new URI[str.length];
220 for (int i = 0; i < str.length;i++){
221 try{
222 uris[i] = new URI(str[i]);
223 }catch(URISyntaxException ur){
224 throw new IllegalArgumentException(
225 "Failed to create uri for " + str[i], ur);
226 }
227 }
228 return uris;
229 }
230
231 /**
232 *
233 * @param str
234 */
235 public static Path[] stringToPath(String[] str){
236 if (str == null) {
237 return null;
238 }
239 Path[] p = new Path[str.length];
240 for (int i = 0; i < str.length;i++){
241 p[i] = new Path(str[i]);
242 }
243 return p;
244 }
245 /**
246 *
247 * Given a finish and start time in long milliseconds, returns a
248 * String in the format Xhrs, Ymins, Z sec, for the time difference between two times.
249 * If finish time comes before start time then negative valeus of X, Y and Z wil return.
250 *
251 * @param finishTime finish time
252 * @param startTime start time
253 */
254 public static String formatTimeDiff(long finishTime, long startTime){
255 long timeDiff = finishTime - startTime;
256 return formatTime(timeDiff);
257 }
258
259 /**
260 *
261 * Given the time in long milliseconds, returns a
262 * String in the format Xhrs, Ymins, Z sec.
263 *
264 * @param timeDiff The time difference to format
265 */
266 public static String formatTime(long timeDiff){
267 StringBuilder buf = new StringBuilder();
268 long hours = timeDiff / (60*60*1000);
269 long rem = (timeDiff % (60*60*1000));
270 long minutes = rem / (60*1000);
271 rem = rem % (60*1000);
272 long seconds = rem / 1000;
273
274 if (hours != 0){
275 buf.append(hours);
276 buf.append("hrs, ");
277 }
278 if (minutes != 0){
279 buf.append(minutes);
280 buf.append("mins, ");
281 }
282 // return "0sec if no difference
283 buf.append(seconds);
284 buf.append("sec");
285 return buf.toString();
286 }
287 /**
288 * Formats time in ms and appends difference (finishTime - startTime)
289 * as returned by formatTimeDiff().
290 * If finish time is 0, empty string is returned, if start time is 0
291 * then difference is not appended to return value.
292 * @param dateFormat date format to use
293 * @param finishTime fnish time
294 * @param startTime start time
295 * @return formatted value.
296 */
297 public static String getFormattedTimeWithDiff(DateFormat dateFormat,
298 long finishTime, long startTime){
299 StringBuilder buf = new StringBuilder();
300 if (0 != finishTime) {
301 buf.append(dateFormat.format(new Date(finishTime)));
302 if (0 != startTime){
303 buf.append(" (" + formatTimeDiff(finishTime , startTime) + ")");
304 }
305 }
306 return buf.toString();
307 }
308
309 /**
310 * Returns an arraylist of strings.
311 * @param str the comma seperated string values
312 * @return the arraylist of the comma seperated string values
313 */
314 public static String[] getStrings(String str){
315 Collection<String> values = getStringCollection(str);
316 if(values.size() == 0) {
317 return null;
318 }
319 return values.toArray(new String[values.size()]);
320 }
321
322 /**
323 * Returns a collection of strings.
324 * @param str comma seperated string values
325 * @return an <code>ArrayList</code> of string values
326 */
327 public static Collection<String> getStringCollection(String str){
328 String delim = ",";
329 return getStringCollection(str, delim);
330 }
331
332 /**
333 * Returns a collection of strings.
334 *
335 * @param str
336 * String to parse
337 * @param delim
338 * delimiter to separate the values
339 * @return Collection of parsed elements.
340 */
341 public static Collection<String> getStringCollection(String str, String delim) {
342 List<String> values = new ArrayList<String>();
343 if (str == null)
344 return values;
345 StringTokenizer tokenizer = new StringTokenizer(str, delim);
346 values = new ArrayList<String>();
347 while (tokenizer.hasMoreTokens()) {
348 values.add(tokenizer.nextToken());
349 }
350 return values;
351 }
352
353 /**
354 * Splits a comma separated value <code>String</code>, trimming leading and trailing whitespace on each value.
355 * @param str a comma separated <String> with values
356 * @return a <code>Collection</code> of <code>String</code> values
357 */
358 public static Collection<String> getTrimmedStringCollection(String str){
359 return new ArrayList<String>(
360 Arrays.asList(getTrimmedStrings(str)));
361 }
362
363 /**
364 * Splits a comma separated value <code>String</code>, trimming leading and trailing whitespace on each value.
365 * @param str a comma separated <String> with values
366 * @return an array of <code>String</code> values
367 */
368 public static String[] getTrimmedStrings(String str){
369 if (null == str || str.trim().isEmpty()) {
370 return emptyStringArray;
371 }
372
373 return str.trim().split("\\s*,\\s*");
374 }
375
376 final public static String[] emptyStringArray = {};
377 final public static char COMMA = ',';
378 final public static String COMMA_STR = ",";
379 final public static char ESCAPE_CHAR = '\\';
380
381 /**
382 * Split a string using the default separator
383 * @param str a string that may have escaped separator
384 * @return an array of strings
385 */
386 public static String[] split(String str) {
387 return split(str, ESCAPE_CHAR, COMMA);
388 }
389
390 /**
391 * Split a string using the given separator
392 * @param str a string that may have escaped separator
393 * @param escapeChar a char that be used to escape the separator
394 * @param separator a separator char
395 * @return an array of strings
396 */
397 public static String[] split(
398 String str, char escapeChar, char separator) {
399 if (str==null) {
400 return null;
401 }
402 ArrayList<String> strList = new ArrayList<String>();
403 StringBuilder split = new StringBuilder();
404 int index = 0;
405 while ((index = findNext(str, separator, escapeChar, index, split)) >= 0) {
406 ++index; // move over the separator for next search
407 strList.add(split.toString());
408 split.setLength(0); // reset the buffer
409 }
410 strList.add(split.toString());
411 // remove trailing empty split(s)
412 int last = strList.size(); // last split
413 while (--last>=0 && "".equals(strList.get(last))) {
414 strList.remove(last);
415 }
416 return strList.toArray(new String[strList.size()]);
417 }
418
419 /**
420 * Split a string using the given separator, with no escaping performed.
421 * @param str a string to be split. Note that this may not be null.
422 * @param separator a separator char
423 * @return an array of strings
424 */
425 public static String[] split(
426 String str, char separator) {
427 // String.split returns a single empty result for splitting the empty
428 // string.
429 if (str.isEmpty()) {
430 return new String[]{""};
431 }
432 ArrayList<String> strList = new ArrayList<String>();
433 int startIndex = 0;
434 int nextIndex = 0;
435 while ((nextIndex = str.indexOf((int)separator, startIndex)) != -1) {
436 strList.add(str.substring(startIndex, nextIndex));
437 startIndex = nextIndex + 1;
438 }
439 strList.add(str.substring(startIndex));
440 // remove trailing empty split(s)
441 int last = strList.size(); // last split
442 while (--last>=0 && "".equals(strList.get(last))) {
443 strList.remove(last);
444 }
445 return strList.toArray(new String[strList.size()]);
446 }
447
448 /**
449 * Finds the first occurrence of the separator character ignoring the escaped
450 * separators starting from the index. Note the substring between the index
451 * and the position of the separator is passed.
452 * @param str the source string
453 * @param separator the character to find
454 * @param escapeChar character used to escape
455 * @param start from where to search
456 * @param split used to pass back the extracted string
457 */
458 public static int findNext(String str, char separator, char escapeChar,
459 int start, StringBuilder split) {
460 int numPreEscapes = 0;
461 for (int i = start; i < str.length(); i++) {
462 char curChar = str.charAt(i);
463 if (numPreEscapes == 0 && curChar == separator) { // separator
464 return i;
465 } else {
466 split.append(curChar);
467 numPreEscapes = (curChar == escapeChar)
468 ? (++numPreEscapes) % 2
469 : 0;
470 }
471 }
472 return -1;
473 }
474
475 /**
476 * Escape commas in the string using the default escape char
477 * @param str a string
478 * @return an escaped string
479 */
480 public static String escapeString(String str) {
481 return escapeString(str, ESCAPE_CHAR, COMMA);
482 }
483
484 /**
485 * Escape <code>charToEscape</code> in the string
486 * with the escape char <code>escapeChar</code>
487 *
488 * @param str string
489 * @param escapeChar escape char
490 * @param charToEscape the char to be escaped
491 * @return an escaped string
492 */
493 public static String escapeString(
494 String str, char escapeChar, char charToEscape) {
495 return escapeString(str, escapeChar, new char[] {charToEscape});
496 }
497
498 // check if the character array has the character
499 private static boolean hasChar(char[] chars, char character) {
500 for (char target : chars) {
501 if (character == target) {
502 return true;
503 }
504 }
505 return false;
506 }
507
508 /**
509 * @param charsToEscape array of characters to be escaped
510 */
511 public static String escapeString(String str, char escapeChar,
512 char[] charsToEscape) {
513 if (str == null) {
514 return null;
515 }
516 StringBuilder result = new StringBuilder();
517 for (int i=0; i<str.length(); i++) {
518 char curChar = str.charAt(i);
519 if (curChar == escapeChar || hasChar(charsToEscape, curChar)) {
520 // special char
521 result.append(escapeChar);
522 }
523 result.append(curChar);
524 }
525 return result.toString();
526 }
527
528 /**
529 * Unescape commas in the string using the default escape char
530 * @param str a string
531 * @return an unescaped string
532 */
533 public static String unEscapeString(String str) {
534 return unEscapeString(str, ESCAPE_CHAR, COMMA);
535 }
536
537 /**
538 * Unescape <code>charToEscape</code> in the string
539 * with the escape char <code>escapeChar</code>
540 *
541 * @param str string
542 * @param escapeChar escape char
543 * @param charToEscape the escaped char
544 * @return an unescaped string
545 */
546 public static String unEscapeString(
547 String str, char escapeChar, char charToEscape) {
548 return unEscapeString(str, escapeChar, new char[] {charToEscape});
549 }
550
551 /**
552 * @param charsToEscape array of characters to unescape
553 */
554 public static String unEscapeString(String str, char escapeChar,
555 char[] charsToEscape) {
556 if (str == null) {
557 return null;
558 }
559 StringBuilder result = new StringBuilder(str.length());
560 boolean hasPreEscape = false;
561 for (int i=0; i<str.length(); i++) {
562 char curChar = str.charAt(i);
563 if (hasPreEscape) {
564 if (curChar != escapeChar && !hasChar(charsToEscape, curChar)) {
565 // no special char
566 throw new IllegalArgumentException("Illegal escaped string " + str +
567 " unescaped " + escapeChar + " at " + (i-1));
568 }
569 // otherwise discard the escape char
570 result.append(curChar);
571 hasPreEscape = false;
572 } else {
573 if (hasChar(charsToEscape, curChar)) {
574 throw new IllegalArgumentException("Illegal escaped string " + str +
575 " unescaped " + curChar + " at " + i);
576 } else if (curChar == escapeChar) {
577 hasPreEscape = true;
578 } else {
579 result.append(curChar);
580 }
581 }
582 }
583 if (hasPreEscape ) {
584 throw new IllegalArgumentException("Illegal escaped string " + str +
585 ", not expecting " + escapeChar + " in the end." );
586 }
587 return result.toString();
588 }
589
590 /**
591 * Return a message for logging.
592 * @param prefix prefix keyword for the message
593 * @param msg content of the message
594 * @return a message for logging
595 */
596 private static String toStartupShutdownString(String prefix, String [] msg) {
597 StringBuilder b = new StringBuilder(prefix);
598 b.append("\n/************************************************************");
599 for(String s : msg)
600 b.append("\n" + prefix + s);
601 b.append("\n************************************************************/");
602 return b.toString();
603 }
604
605 /**
606 * Print a log message for starting up and shutting down
607 * @param clazz the class of the server
608 * @param args arguments
609 * @param LOG the target log object
610 */
611 public static void startupShutdownMessage(Class<?> clazz, String[] args,
612 final org.apache.commons.logging.Log LOG) {
613 final String hostname = NetUtils.getHostname();
614 final String classname = clazz.getSimpleName();
615 LOG.info(
616 toStartupShutdownString("STARTUP_MSG: ", new String[] {
617 "Starting " + classname,
618 " host = " + hostname,
619 " args = " + Arrays.asList(args),
620 " version = " + VersionInfo.getVersion(),
621 " classpath = " + System.getProperty("java.class.path"),
622 " build = " + VersionInfo.getUrl() + " -r "
623 + VersionInfo.getRevision()
624 + "; compiled by '" + VersionInfo.getUser()
625 + "' on " + VersionInfo.getDate(),
626 " java = " + System.getProperty("java.version") }
627 )
628 );
629
630 if (SystemUtils.IS_OS_UNIX) {
631 try {
632 SignalLogger.INSTANCE.register(LOG);
633 } catch (Throwable t) {
634 LOG.warn("failed to register any UNIX signal loggers: ", t);
635 }
636 }
637 ShutdownHookManager.get().addShutdownHook(
638 new Runnable() {
639 @Override
640 public void run() {
641 LOG.info(toStartupShutdownString("SHUTDOWN_MSG: ", new String[]{
642 "Shutting down " + classname + " at " + hostname}));
643 }
644 }, SHUTDOWN_HOOK_PRIORITY);
645
646 }
647
648 /**
649 * The traditional binary prefixes, kilo, mega, ..., exa,
650 * which can be represented by a 64-bit integer.
651 * TraditionalBinaryPrefix symbol are case insensitive.
652 */
653 public static enum TraditionalBinaryPrefix {
654 KILO(10),
655 MEGA(KILO.bitShift + 10),
656 GIGA(MEGA.bitShift + 10),
657 TERA(GIGA.bitShift + 10),
658 PETA(TERA.bitShift + 10),
659 EXA (PETA.bitShift + 10);
660
661 public final long value;
662 public final char symbol;
663 public final int bitShift;
664 public final long bitMask;
665
666 private TraditionalBinaryPrefix(int bitShift) {
667 this.bitShift = bitShift;
668 this.value = 1L << bitShift;
669 this.bitMask = this.value - 1L;
670 this.symbol = toString().charAt(0);
671 }
672
673 /**
674 * @return The TraditionalBinaryPrefix object corresponding to the symbol.
675 */
676 public static TraditionalBinaryPrefix valueOf(char symbol) {
677 symbol = Character.toUpperCase(symbol);
678 for(TraditionalBinaryPrefix prefix : TraditionalBinaryPrefix.values()) {
679 if (symbol == prefix.symbol) {
680 return prefix;
681 }
682 }
683 throw new IllegalArgumentException("Unknown symbol '" + symbol + "'");
684 }
685
686 /**
687 * Convert a string to long.
688 * The input string is first be trimmed
689 * and then it is parsed with traditional binary prefix.
690 *
691 * For example,
692 * "-1230k" will be converted to -1230 * 1024 = -1259520;
693 * "891g" will be converted to 891 * 1024^3 = 956703965184;
694 *
695 * @param s input string
696 * @return a long value represented by the input string.
697 */
698 public static long string2long(String s) {
699 s = s.trim();
700 final int lastpos = s.length() - 1;
701 final char lastchar = s.charAt(lastpos);
702 if (Character.isDigit(lastchar))
703 return Long.parseLong(s);
704 else {
705 long prefix;
706 try {
707 prefix = TraditionalBinaryPrefix.valueOf(lastchar).value;
708 } catch (IllegalArgumentException e) {
709 throw new IllegalArgumentException("Invalid size prefix '" + lastchar
710 + "' in '" + s
711 + "'. Allowed prefixes are k, m, g, t, p, e(case insensitive)");
712 }
713 long num = Long.parseLong(s.substring(0, lastpos));
714 if (num > (Long.MAX_VALUE/prefix) || num < (Long.MIN_VALUE/prefix)) {
715 throw new IllegalArgumentException(s + " does not fit in a Long");
716 }
717 return num * prefix;
718 }
719 }
720
721 /**
722 * Convert a long integer to a string with traditional binary prefix.
723 *
724 * @param n the value to be converted
725 * @param unit The unit, e.g. "B" for bytes.
726 * @param decimalPlaces The number of decimal places.
727 * @return a string with traditional binary prefix.
728 */
729 public static String long2String(long n, String unit, int decimalPlaces) {
730 if (unit == null) {
731 unit = "";
732 }
733 //take care a special case
734 if (n == Long.MIN_VALUE) {
735 return "-8 " + EXA.symbol + unit;
736 }
737
738 final StringBuilder b = new StringBuilder();
739 //take care negative numbers
740 if (n < 0) {
741 b.append('-');
742 n = -n;
743 }
744 if (n < KILO.value) {
745 //no prefix
746 b.append(n);
747 return (unit.isEmpty()? b: b.append(" ").append(unit)).toString();
748 } else {
749 //find traditional binary prefix
750 int i = 0;
751 for(; i < values().length && n >= values()[i].value; i++);
752 TraditionalBinaryPrefix prefix = values()[i - 1];
753
754 if ((n & prefix.bitMask) == 0) {
755 //exact division
756 b.append(n >> prefix.bitShift);
757 } else {
758 final String format = "%." + decimalPlaces + "f";
759 String s = format(format, n/(double)prefix.value);
760 //check a special rounding up case
761 if (s.startsWith("1024")) {
762 prefix = values()[i];
763 s = format(format, n/(double)prefix.value);
764 }
765 b.append(s);
766 }
767 return b.append(' ').append(prefix.symbol).append(unit).toString();
768 }
769 }
770 }
771
772 /**
773 * Escapes HTML Special characters present in the string.
774 * @param string
775 * @return HTML Escaped String representation
776 */
777 public static String escapeHTML(String string) {
778 if(string == null) {
779 return null;
780 }
781 StringBuilder sb = new StringBuilder();
782 boolean lastCharacterWasSpace = false;
783 char[] chars = string.toCharArray();
784 for(char c : chars) {
785 if(c == ' ') {
786 if(lastCharacterWasSpace){
787 lastCharacterWasSpace = false;
788 sb.append(" ");
789 }else {
790 lastCharacterWasSpace=true;
791 sb.append(" ");
792 }
793 }else {
794 lastCharacterWasSpace = false;
795 switch(c) {
796 case '<': sb.append("<"); break;
797 case '>': sb.append(">"); break;
798 case '&': sb.append("&"); break;
799 case '"': sb.append("""); break;
800 default : sb.append(c);break;
801 }
802 }
803 }
804
805 return sb.toString();
806 }
807
808 /**
809 * @return a byte description of the given long interger value.
810 */
811 public static String byteDesc(long len) {
812 return TraditionalBinaryPrefix.long2String(len, "B", 2);
813 }
814
815 /** @deprecated use StringUtils.format("%.2f", d). */
816 @Deprecated
817 public static String limitDecimalTo2(double d) {
818 return format("%.2f", d);
819 }
820
821 /**
822 * Concatenates strings, using a separator.
823 *
824 * @param separator Separator to join with.
825 * @param strings Strings to join.
826 */
827 public static String join(CharSequence separator, Iterable<?> strings) {
828 Iterator<?> i = strings.iterator();
829 if (!i.hasNext()) {
830 return "";
831 }
832 StringBuilder sb = new StringBuilder(i.next().toString());
833 while (i.hasNext()) {
834 sb.append(separator);
835 sb.append(i.next().toString());
836 }
837 return sb.toString();
838 }
839
840 /**
841 * Concatenates strings, using a separator.
842 *
843 * @param separator to join with
844 * @param strings to join
845 * @return the joined string
846 */
847 public static String join(CharSequence separator, String[] strings) {
848 // Ideally we don't have to duplicate the code here if array is iterable.
849 StringBuilder sb = new StringBuilder();
850 boolean first = true;
851 for (String s : strings) {
852 if (first) {
853 first = false;
854 } else {
855 sb.append(separator);
856 }
857 sb.append(s);
858 }
859 return sb.toString();
860 }
861
862 /**
863 * Convert SOME_STUFF to SomeStuff
864 *
865 * @param s input string
866 * @return camelized string
867 */
868 public static String camelize(String s) {
869 StringBuilder sb = new StringBuilder();
870 String[] words = split(s.toLowerCase(Locale.US), ESCAPE_CHAR, '_');
871
872 for (String word : words)
873 sb.append(org.apache.commons.lang.StringUtils.capitalize(word));
874
875 return sb.toString();
876 }
877
878 /**
879 * Matches a template string against a pattern, replaces matched tokens with
880 * the supplied replacements, and returns the result. The regular expression
881 * must use a capturing group. The value of the first capturing group is used
882 * to look up the replacement. If no replacement is found for the token, then
883 * it is replaced with the empty string.
884 *
885 * For example, assume template is "%foo%_%bar%_%baz%", pattern is "%(.*?)%",
886 * and replacements contains 2 entries, mapping "foo" to "zoo" and "baz" to
887 * "zaz". The result returned would be "zoo__zaz".
888 *
889 * @param template String template to receive replacements
890 * @param pattern Pattern to match for identifying tokens, must use a capturing
891 * group
892 * @param replacements Map<String, String> mapping tokens identified by the
893 * capturing group to their replacement values
894 * @return String template with replacements
895 */
896 public static String replaceTokens(String template, Pattern pattern,
897 Map<String, String> replacements) {
898 StringBuffer sb = new StringBuffer();
899 Matcher matcher = pattern.matcher(template);
900 while (matcher.find()) {
901 String replacement = replacements.get(matcher.group(1));
902 if (replacement == null) {
903 replacement = "";
904 }
905 matcher.appendReplacement(sb, Matcher.quoteReplacement(replacement));
906 }
907 matcher.appendTail(sb);
908 return sb.toString();
909 }
910
911 /**
912 * Get stack trace for a given thread.
913 */
914 public static String getStackTrace(Thread t) {
915 final StackTraceElement[] stackTrace = t.getStackTrace();
916 StringBuilder str = new StringBuilder();
917 for (StackTraceElement e : stackTrace) {
918 str.append(e.toString() + "\n");
919 }
920 return str.toString();
921 }
922 }