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 List<String> values = new ArrayList<String>();
329 if (str == null)
330 return values;
331 StringTokenizer tokenizer = new StringTokenizer (str,",");
332 values = new ArrayList<String>();
333 while (tokenizer.hasMoreTokens()) {
334 values.add(tokenizer.nextToken());
335 }
336 return values;
337 }
338
339 /**
340 * Splits a comma separated value <code>String</code>, trimming leading and trailing whitespace on each value.
341 * @param str a comma separated <String> with values
342 * @return a <code>Collection</code> of <code>String</code> values
343 */
344 public static Collection<String> getTrimmedStringCollection(String str){
345 return new ArrayList<String>(
346 Arrays.asList(getTrimmedStrings(str)));
347 }
348
349 /**
350 * Splits a comma separated value <code>String</code>, trimming leading and trailing whitespace on each value.
351 * @param str a comma separated <String> with values
352 * @return an array of <code>String</code> values
353 */
354 public static String[] getTrimmedStrings(String str){
355 if (null == str || "".equals(str.trim())) {
356 return emptyStringArray;
357 }
358
359 return str.trim().split("\\s*,\\s*");
360 }
361
362 final public static String[] emptyStringArray = {};
363 final public static char COMMA = ',';
364 final public static String COMMA_STR = ",";
365 final public static char ESCAPE_CHAR = '\\';
366
367 /**
368 * Split a string using the default separator
369 * @param str a string that may have escaped separator
370 * @return an array of strings
371 */
372 public static String[] split(String str) {
373 return split(str, ESCAPE_CHAR, COMMA);
374 }
375
376 /**
377 * Split a string using the given separator
378 * @param str a string that may have escaped separator
379 * @param escapeChar a char that be used to escape the separator
380 * @param separator a separator char
381 * @return an array of strings
382 */
383 public static String[] split(
384 String str, char escapeChar, char separator) {
385 if (str==null) {
386 return null;
387 }
388 ArrayList<String> strList = new ArrayList<String>();
389 StringBuilder split = new StringBuilder();
390 int index = 0;
391 while ((index = findNext(str, separator, escapeChar, index, split)) >= 0) {
392 ++index; // move over the separator for next search
393 strList.add(split.toString());
394 split.setLength(0); // reset the buffer
395 }
396 strList.add(split.toString());
397 // remove trailing empty split(s)
398 int last = strList.size(); // last split
399 while (--last>=0 && "".equals(strList.get(last))) {
400 strList.remove(last);
401 }
402 return strList.toArray(new String[strList.size()]);
403 }
404
405 /**
406 * Split a string using the given separator, with no escaping performed.
407 * @param str a string to be split. Note that this may not be null.
408 * @param separator a separator char
409 * @return an array of strings
410 */
411 public static String[] split(
412 String str, char separator) {
413 // String.split returns a single empty result for splitting the empty
414 // string.
415 if ("".equals(str)) {
416 return new String[]{""};
417 }
418 ArrayList<String> strList = new ArrayList<String>();
419 int startIndex = 0;
420 int nextIndex = 0;
421 while ((nextIndex = str.indexOf((int)separator, startIndex)) != -1) {
422 strList.add(str.substring(startIndex, nextIndex));
423 startIndex = nextIndex + 1;
424 }
425 strList.add(str.substring(startIndex));
426 // remove trailing empty split(s)
427 int last = strList.size(); // last split
428 while (--last>=0 && "".equals(strList.get(last))) {
429 strList.remove(last);
430 }
431 return strList.toArray(new String[strList.size()]);
432 }
433
434 /**
435 * Finds the first occurrence of the separator character ignoring the escaped
436 * separators starting from the index. Note the substring between the index
437 * and the position of the separator is passed.
438 * @param str the source string
439 * @param separator the character to find
440 * @param escapeChar character used to escape
441 * @param start from where to search
442 * @param split used to pass back the extracted string
443 */
444 public static int findNext(String str, char separator, char escapeChar,
445 int start, StringBuilder split) {
446 int numPreEscapes = 0;
447 for (int i = start; i < str.length(); i++) {
448 char curChar = str.charAt(i);
449 if (numPreEscapes == 0 && curChar == separator) { // separator
450 return i;
451 } else {
452 split.append(curChar);
453 numPreEscapes = (curChar == escapeChar)
454 ? (++numPreEscapes) % 2
455 : 0;
456 }
457 }
458 return -1;
459 }
460
461 /**
462 * Escape commas in the string using the default escape char
463 * @param str a string
464 * @return an escaped string
465 */
466 public static String escapeString(String str) {
467 return escapeString(str, ESCAPE_CHAR, COMMA);
468 }
469
470 /**
471 * Escape <code>charToEscape</code> in the string
472 * with the escape char <code>escapeChar</code>
473 *
474 * @param str string
475 * @param escapeChar escape char
476 * @param charToEscape the char to be escaped
477 * @return an escaped string
478 */
479 public static String escapeString(
480 String str, char escapeChar, char charToEscape) {
481 return escapeString(str, escapeChar, new char[] {charToEscape});
482 }
483
484 // check if the character array has the character
485 private static boolean hasChar(char[] chars, char character) {
486 for (char target : chars) {
487 if (character == target) {
488 return true;
489 }
490 }
491 return false;
492 }
493
494 /**
495 * @param charsToEscape array of characters to be escaped
496 */
497 public static String escapeString(String str, char escapeChar,
498 char[] charsToEscape) {
499 if (str == null) {
500 return null;
501 }
502 StringBuilder result = new StringBuilder();
503 for (int i=0; i<str.length(); i++) {
504 char curChar = str.charAt(i);
505 if (curChar == escapeChar || hasChar(charsToEscape, curChar)) {
506 // special char
507 result.append(escapeChar);
508 }
509 result.append(curChar);
510 }
511 return result.toString();
512 }
513
514 /**
515 * Unescape commas in the string using the default escape char
516 * @param str a string
517 * @return an unescaped string
518 */
519 public static String unEscapeString(String str) {
520 return unEscapeString(str, ESCAPE_CHAR, COMMA);
521 }
522
523 /**
524 * Unescape <code>charToEscape</code> in the string
525 * with the escape char <code>escapeChar</code>
526 *
527 * @param str string
528 * @param escapeChar escape char
529 * @param charToEscape the escaped char
530 * @return an unescaped string
531 */
532 public static String unEscapeString(
533 String str, char escapeChar, char charToEscape) {
534 return unEscapeString(str, escapeChar, new char[] {charToEscape});
535 }
536
537 /**
538 * @param charsToEscape array of characters to unescape
539 */
540 public static String unEscapeString(String str, char escapeChar,
541 char[] charsToEscape) {
542 if (str == null) {
543 return null;
544 }
545 StringBuilder result = new StringBuilder(str.length());
546 boolean hasPreEscape = false;
547 for (int i=0; i<str.length(); i++) {
548 char curChar = str.charAt(i);
549 if (hasPreEscape) {
550 if (curChar != escapeChar && !hasChar(charsToEscape, curChar)) {
551 // no special char
552 throw new IllegalArgumentException("Illegal escaped string " + str +
553 " unescaped " + escapeChar + " at " + (i-1));
554 }
555 // otherwise discard the escape char
556 result.append(curChar);
557 hasPreEscape = false;
558 } else {
559 if (hasChar(charsToEscape, curChar)) {
560 throw new IllegalArgumentException("Illegal escaped string " + str +
561 " unescaped " + curChar + " at " + i);
562 } else if (curChar == escapeChar) {
563 hasPreEscape = true;
564 } else {
565 result.append(curChar);
566 }
567 }
568 }
569 if (hasPreEscape ) {
570 throw new IllegalArgumentException("Illegal escaped string " + str +
571 ", not expecting " + escapeChar + " in the end." );
572 }
573 return result.toString();
574 }
575
576 /**
577 * Return a message for logging.
578 * @param prefix prefix keyword for the message
579 * @param msg content of the message
580 * @return a message for logging
581 */
582 private static String toStartupShutdownString(String prefix, String [] msg) {
583 StringBuilder b = new StringBuilder(prefix);
584 b.append("\n/************************************************************");
585 for(String s : msg)
586 b.append("\n" + prefix + s);
587 b.append("\n************************************************************/");
588 return b.toString();
589 }
590
591 /**
592 * Print a log message for starting up and shutting down
593 * @param clazz the class of the server
594 * @param args arguments
595 * @param LOG the target log object
596 */
597 public static void startupShutdownMessage(Class<?> clazz, String[] args,
598 final org.apache.commons.logging.Log LOG) {
599 final String hostname = NetUtils.getHostname();
600 final String classname = clazz.getSimpleName();
601 LOG.info(
602 toStartupShutdownString("STARTUP_MSG: ", new String[] {
603 "Starting " + classname,
604 " host = " + hostname,
605 " args = " + Arrays.asList(args),
606 " version = " + VersionInfo.getVersion(),
607 " classpath = " + System.getProperty("java.class.path"),
608 " build = " + VersionInfo.getUrl() + " -r "
609 + VersionInfo.getRevision()
610 + "; compiled by '" + VersionInfo.getUser()
611 + "' on " + VersionInfo.getDate(),
612 " java = " + System.getProperty("java.version") }
613 )
614 );
615
616 if (SystemUtils.IS_OS_UNIX) {
617 try {
618 SignalLogger.INSTANCE.register(LOG);
619 } catch (Throwable t) {
620 LOG.warn("failed to register any UNIX signal loggers: ", t);
621 }
622 }
623 ShutdownHookManager.get().addShutdownHook(
624 new Runnable() {
625 @Override
626 public void run() {
627 LOG.info(toStartupShutdownString("SHUTDOWN_MSG: ", new String[]{
628 "Shutting down " + classname + " at " + hostname}));
629 }
630 }, SHUTDOWN_HOOK_PRIORITY);
631
632 }
633
634 /**
635 * The traditional binary prefixes, kilo, mega, ..., exa,
636 * which can be represented by a 64-bit integer.
637 * TraditionalBinaryPrefix symbol are case insensitive.
638 */
639 public static enum TraditionalBinaryPrefix {
640 KILO(10),
641 MEGA(KILO.bitShift + 10),
642 GIGA(MEGA.bitShift + 10),
643 TERA(GIGA.bitShift + 10),
644 PETA(TERA.bitShift + 10),
645 EXA (PETA.bitShift + 10);
646
647 public final long value;
648 public final char symbol;
649 public final int bitShift;
650 public final long bitMask;
651
652 private TraditionalBinaryPrefix(int bitShift) {
653 this.bitShift = bitShift;
654 this.value = 1L << bitShift;
655 this.bitMask = this.value - 1L;
656 this.symbol = toString().charAt(0);
657 }
658
659 /**
660 * @return The TraditionalBinaryPrefix object corresponding to the symbol.
661 */
662 public static TraditionalBinaryPrefix valueOf(char symbol) {
663 symbol = Character.toUpperCase(symbol);
664 for(TraditionalBinaryPrefix prefix : TraditionalBinaryPrefix.values()) {
665 if (symbol == prefix.symbol) {
666 return prefix;
667 }
668 }
669 throw new IllegalArgumentException("Unknown symbol '" + symbol + "'");
670 }
671
672 /**
673 * Convert a string to long.
674 * The input string is first be trimmed
675 * and then it is parsed with traditional binary prefix.
676 *
677 * For example,
678 * "-1230k" will be converted to -1230 * 1024 = -1259520;
679 * "891g" will be converted to 891 * 1024^3 = 956703965184;
680 *
681 * @param s input string
682 * @return a long value represented by the input string.
683 */
684 public static long string2long(String s) {
685 s = s.trim();
686 final int lastpos = s.length() - 1;
687 final char lastchar = s.charAt(lastpos);
688 if (Character.isDigit(lastchar))
689 return Long.parseLong(s);
690 else {
691 long prefix;
692 try {
693 prefix = TraditionalBinaryPrefix.valueOf(lastchar).value;
694 } catch (IllegalArgumentException e) {
695 throw new IllegalArgumentException("Invalid size prefix '" + lastchar
696 + "' in '" + s
697 + "'. Allowed prefixes are k, m, g, t, p, e(case insensitive)");
698 }
699 long num = Long.parseLong(s.substring(0, lastpos));
700 if (num > (Long.MAX_VALUE/prefix) || num < (Long.MIN_VALUE/prefix)) {
701 throw new IllegalArgumentException(s + " does not fit in a Long");
702 }
703 return num * prefix;
704 }
705 }
706
707 /**
708 * Convert a long integer to a string with traditional binary prefix.
709 *
710 * @param n the value to be converted
711 * @param unit The unit, e.g. "B" for bytes.
712 * @param decimalPlaces The number of decimal places.
713 * @return a string with traditional binary prefix.
714 */
715 public static String long2String(long n, String unit, int decimalPlaces) {
716 if (unit == null) {
717 unit = "";
718 }
719 //take care a special case
720 if (n == Long.MIN_VALUE) {
721 return "-8 " + EXA.symbol + unit;
722 }
723
724 final StringBuilder b = new StringBuilder();
725 //take care negative numbers
726 if (n < 0) {
727 b.append('-');
728 n = -n;
729 }
730 if (n < KILO.value) {
731 //no prefix
732 b.append(n);
733 return (unit.isEmpty()? b: b.append(" ").append(unit)).toString();
734 } else {
735 //find traditional binary prefix
736 int i = 0;
737 for(; i < values().length && n >= values()[i].value; i++);
738 TraditionalBinaryPrefix prefix = values()[i - 1];
739
740 if ((n & prefix.bitMask) == 0) {
741 //exact division
742 b.append(n >> prefix.bitShift);
743 } else {
744 final String format = "%." + decimalPlaces + "f";
745 String s = format(format, n/(double)prefix.value);
746 //check a special rounding up case
747 if (s.startsWith("1024")) {
748 prefix = values()[i];
749 s = format(format, n/(double)prefix.value);
750 }
751 b.append(s);
752 }
753 return b.append(' ').append(prefix.symbol).append(unit).toString();
754 }
755 }
756 }
757
758 /**
759 * Escapes HTML Special characters present in the string.
760 * @param string
761 * @return HTML Escaped String representation
762 */
763 public static String escapeHTML(String string) {
764 if(string == null) {
765 return null;
766 }
767 StringBuilder sb = new StringBuilder();
768 boolean lastCharacterWasSpace = false;
769 char[] chars = string.toCharArray();
770 for(char c : chars) {
771 if(c == ' ') {
772 if(lastCharacterWasSpace){
773 lastCharacterWasSpace = false;
774 sb.append(" ");
775 }else {
776 lastCharacterWasSpace=true;
777 sb.append(" ");
778 }
779 }else {
780 lastCharacterWasSpace = false;
781 switch(c) {
782 case '<': sb.append("<"); break;
783 case '>': sb.append(">"); break;
784 case '&': sb.append("&"); break;
785 case '"': sb.append("""); break;
786 default : sb.append(c);break;
787 }
788 }
789 }
790
791 return sb.toString();
792 }
793
794 /**
795 * @return a byte description of the given long interger value.
796 */
797 public static String byteDesc(long len) {
798 return TraditionalBinaryPrefix.long2String(len, "B", 2);
799 }
800
801 /** @deprecated use StringUtils.format("%.2f", d). */
802 @Deprecated
803 public static String limitDecimalTo2(double d) {
804 return format("%.2f", d);
805 }
806
807 /**
808 * Concatenates strings, using a separator.
809 *
810 * @param separator Separator to join with.
811 * @param strings Strings to join.
812 */
813 public static String join(CharSequence separator, Iterable<?> strings) {
814 Iterator<?> i = strings.iterator();
815 if (!i.hasNext()) {
816 return "";
817 }
818 StringBuilder sb = new StringBuilder(i.next().toString());
819 while (i.hasNext()) {
820 sb.append(separator);
821 sb.append(i.next().toString());
822 }
823 return sb.toString();
824 }
825
826 /**
827 * Concatenates strings, using a separator.
828 *
829 * @param separator to join with
830 * @param strings to join
831 * @return the joined string
832 */
833 public static String join(CharSequence separator, String[] strings) {
834 // Ideally we don't have to duplicate the code here if array is iterable.
835 StringBuilder sb = new StringBuilder();
836 boolean first = true;
837 for (String s : strings) {
838 if (first) {
839 first = false;
840 } else {
841 sb.append(separator);
842 }
843 sb.append(s);
844 }
845 return sb.toString();
846 }
847
848 /**
849 * Convert SOME_STUFF to SomeStuff
850 *
851 * @param s input string
852 * @return camelized string
853 */
854 public static String camelize(String s) {
855 StringBuilder sb = new StringBuilder();
856 String[] words = split(s.toLowerCase(Locale.US), ESCAPE_CHAR, '_');
857
858 for (String word : words)
859 sb.append(org.apache.commons.lang.StringUtils.capitalize(word));
860
861 return sb.toString();
862 }
863
864 /**
865 * Matches a template string against a pattern, replaces matched tokens with
866 * the supplied replacements, and returns the result. The regular expression
867 * must use a capturing group. The value of the first capturing group is used
868 * to look up the replacement. If no replacement is found for the token, then
869 * it is replaced with the empty string.
870 *
871 * For example, assume template is "%foo%_%bar%_%baz%", pattern is "%(.*?)%",
872 * and replacements contains 2 entries, mapping "foo" to "zoo" and "baz" to
873 * "zaz". The result returned would be "zoo__zaz".
874 *
875 * @param template String template to receive replacements
876 * @param pattern Pattern to match for identifying tokens, must use a capturing
877 * group
878 * @param replacements Map<String, String> mapping tokens identified by the
879 * capturing group to their replacement values
880 * @return String template with replacements
881 */
882 public static String replaceTokens(String template, Pattern pattern,
883 Map<String, String> replacements) {
884 StringBuffer sb = new StringBuffer();
885 Matcher matcher = pattern.matcher(template);
886 while (matcher.find()) {
887 String replacement = replacements.get(matcher.group(1));
888 if (replacement == null) {
889 replacement = "";
890 }
891 matcher.appendReplacement(sb, Matcher.quoteReplacement(replacement));
892 }
893 matcher.appendTail(sb);
894 return sb.toString();
895 }
896
897 /**
898 * Get stack trace for a given thread.
899 */
900 public static String getStackTrace(Thread t) {
901 final StackTraceElement[] stackTrace = t.getStackTrace();
902 StringBuilder str = new StringBuilder();
903 for (StackTraceElement e : stackTrace) {
904 str.append(e.toString() + "\n");
905 }
906 return str.toString();
907 }
908 }