/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.apache.sshd.common.util; import java.io.File; import java.nio.file.FileSystem; import java.util.ArrayList; import java.util.List; import java.util.Objects; import java.util.StringTokenizer; /** * <p>This is a utility class used by selectors and DirectoryScanner. The * functionality more properly belongs just to selectors, but unfortunately * DirectoryScanner exposed these as protected methods. Thus we have to * support any subclasses of DirectoryScanner that may access these methods. * </p> * <p>This is a Singleton.</p> * * @author Arnout J. Kuiper * <a href="mailto:ajkuiper@wxs.nl">ajkuiper@wxs.nl</a> * @author Magesh Umasankar * @author <a href="mailto:bruce@callenish.com">Bruce Atherton</a> * @version $Id$ * @since 1.5 */ public final class SelectorUtils { public static final String PATTERN_HANDLER_PREFIX = "["; public static final String PATTERN_HANDLER_SUFFIX = "]"; public static final String REGEX_HANDLER_PREFIX = "%regex" + PATTERN_HANDLER_PREFIX; public static final String ANT_HANDLER_PREFIX = "%ant" + PATTERN_HANDLER_PREFIX; /** * Private Constructor */ private SelectorUtils() { throw new UnsupportedOperationException("No instance allowed"); } /** * <p>Tests whether or not a given path matches the start of a given * pattern up to the first "**".</p> * * <p>This is not a general purpose test and should only be used if you * can live with false positives. For example, <code>pattern=**\a</code> * and <code>str=b</code> will yield <code>true</code>.</p> * * @param pattern The pattern to match against. Must not be * {@code null}. * @param str The path to match, as a String. Must not be * {@code null}. * @return whether or not a given path matches the start of a given * pattern up to the first "**". */ public static boolean matchPatternStart(String pattern, String str) { return matchPatternStart(pattern, str, true); } /** * <p>Tests whether or not a given path matches the start of a given * pattern up to the first "**".</p> * * <p>This is not a general purpose test and should only be used if you * can live with false positives. For example, <code>pattern=**\a</code> * and <code>str=b</code> will yield <code>true</code>.</p> * * @param pattern The pattern to match against. Must not be * {@code null}. * @param str The path to match, as a String. Must not be * {@code null}. * @param isCaseSensitive Whether or not matching should be performed * case sensitively. * @return whether or not a given path matches the start of a given * pattern up to the first "**". */ public static boolean matchPatternStart(String pattern, String str, boolean isCaseSensitive) { if (pattern.length() > (REGEX_HANDLER_PREFIX.length() + PATTERN_HANDLER_SUFFIX.length() + 1) && pattern.startsWith(REGEX_HANDLER_PREFIX) && pattern.endsWith(PATTERN_HANDLER_SUFFIX)) { // FIXME: ICK! But we can't do partial matches for regex, so we have to reserve judgement until we have // a file to deal with, or we can definitely say this is an exclusion... return true; } else { if (pattern.length() > (ANT_HANDLER_PREFIX.length() + PATTERN_HANDLER_SUFFIX.length() + 1) && pattern.startsWith(ANT_HANDLER_PREFIX) && pattern.endsWith(PATTERN_HANDLER_SUFFIX)) { pattern = pattern.substring(ANT_HANDLER_PREFIX.length(), pattern.length() - PATTERN_HANDLER_SUFFIX.length()); } String altStr = str.replace('\\', '/'); return matchAntPathPatternStart(pattern, str, File.separator, isCaseSensitive) || matchAntPathPatternStart(pattern, altStr, "/", isCaseSensitive); } } private static boolean matchAntPathPatternStart(String pattern, String str, String separator, boolean isCaseSensitive) { // When str starts with a File.separator, pattern has to start with a // File.separator. // When pattern starts with a File.separator, str has to start with a // File.separator. if (str.startsWith(separator) != pattern.startsWith(separator)) { return false; } List<String> patDirs = tokenizePath(pattern, separator); List<String> strDirs = tokenizePath(str, separator); int patIdxStart = 0; int patIdxEnd = patDirs.size() - 1; int strIdxStart = 0; int strIdxEnd = strDirs.size() - 1; // up to first '**' while (patIdxStart <= patIdxEnd && strIdxStart <= strIdxEnd) { String patDir = patDirs.get(patIdxStart); if (patDir.equals("**")) { break; } if (!match(patDir, strDirs.get(strIdxStart), isCaseSensitive)) { return false; } patIdxStart++; strIdxStart++; } // CHECKSTYLE:OFF if (strIdxStart > strIdxEnd) { // String is exhausted return true; } else return patIdxStart <= patIdxEnd; // CHECKSTYLE:ON } /** * Tests whether or not a given path matches a given pattern. * * @param pattern The pattern to match against. Must not be * {@code null}. * @param str The path to match, as a String. Must not be * {@code null}. * @return <code>true</code> if the pattern matches against the string, * or <code>false</code> otherwise. */ public static boolean matchPath(String pattern, String str) { return matchPath(pattern, str, true); } /** * Tests whether or not a given path matches a given pattern. * * @param pattern The pattern to match against. Must not be * {@code null}. * @param str The path to match, as a String. Must not be * {@code null}. * @param isCaseSensitive Whether or not matching should be performed * case sensitively. * @return <code>true</code> if the pattern matches against the string, * or <code>false</code> otherwise. */ public static boolean matchPath(String pattern, String str, boolean isCaseSensitive) { if (pattern.length() > (REGEX_HANDLER_PREFIX.length() + PATTERN_HANDLER_SUFFIX.length() + 1) && pattern.startsWith(REGEX_HANDLER_PREFIX) && pattern.endsWith(PATTERN_HANDLER_SUFFIX)) { pattern = pattern.substring(REGEX_HANDLER_PREFIX.length(), pattern.length() - PATTERN_HANDLER_SUFFIX.length()); return str.matches(pattern); } else { if (pattern.length() > (ANT_HANDLER_PREFIX.length() + PATTERN_HANDLER_SUFFIX.length() + 1) && pattern.startsWith(ANT_HANDLER_PREFIX) && pattern.endsWith(PATTERN_HANDLER_SUFFIX)) { pattern = pattern.substring(ANT_HANDLER_PREFIX.length(), pattern.length() - PATTERN_HANDLER_SUFFIX.length()); } return matchAntPathPattern(pattern, str, isCaseSensitive); } } private static boolean matchAntPathPattern(String pattern, String str, boolean isCaseSensitive) { // When str starts with a File.separator, pattern has to start with a // File.separator. // When pattern starts with a File.separator, str has to start with a // File.separator. if (str.startsWith(File.separator) != pattern.startsWith(File.separator)) { return false; } List<String> patDirs = tokenizePath(pattern, File.separator); List<String> strDirs = tokenizePath(str, File.separator); int patIdxStart = 0; int patIdxEnd = patDirs.size() - 1; int strIdxStart = 0; int strIdxEnd = strDirs.size() - 1; // up to first '**' while (patIdxStart <= patIdxEnd && strIdxStart <= strIdxEnd) { String patDir = patDirs.get(patIdxStart); if (patDir.equals("**")) { break; } if (!match(patDir, strDirs.get(strIdxStart), isCaseSensitive)) { patDirs = null; strDirs = null; return false; } patIdxStart++; strIdxStart++; } if (strIdxStart > strIdxEnd) { // String is exhausted for (int i = patIdxStart; i <= patIdxEnd; i++) { if (!patDirs.get(i).equals("**")) { patDirs = null; strDirs = null; return false; } } return true; } else { if (patIdxStart > patIdxEnd) { // String not exhausted, but pattern is. Failure. patDirs = null; strDirs = null; return false; } } // up to last '**' while (patIdxStart <= patIdxEnd && strIdxStart <= strIdxEnd) { String patDir = patDirs.get(patIdxEnd); if (patDir.equals("**")) { break; } if (!match(patDir, strDirs.get(strIdxEnd), isCaseSensitive)) { patDirs = null; strDirs = null; return false; } patIdxEnd--; strIdxEnd--; } if (strIdxStart > strIdxEnd) { // String is exhausted for (int i = patIdxStart; i <= patIdxEnd; i++) { if (!patDirs.get(i).equals("**")) { patDirs = null; strDirs = null; return false; } } return true; } while (patIdxStart != patIdxEnd && strIdxStart <= strIdxEnd) { int patIdxTmp = -1; for (int i = patIdxStart + 1; i <= patIdxEnd; i++) { if (patDirs.get(i).equals("**")) { patIdxTmp = i; break; } } if (patIdxTmp == patIdxStart + 1) { // '**/**' situation, so skip one patIdxStart++; continue; } // Find the pattern between padIdxStart & padIdxTmp in str between // strIdxStart & strIdxEnd int patLength = patIdxTmp - patIdxStart - 1; int strLength = strIdxEnd - strIdxStart + 1; int foundIdx = -1; strLoop: for (int i = 0; i <= strLength - patLength; i++) { for (int j = 0; j < patLength; j++) { String subPat = patDirs.get(patIdxStart + j + 1); String subStr = strDirs.get(strIdxStart + i + j); if (!match(subPat, subStr, isCaseSensitive)) { continue strLoop; } } foundIdx = strIdxStart + i; break; } if (foundIdx == -1) { patDirs = null; strDirs = null; return false; } patIdxStart = patIdxTmp; strIdxStart = foundIdx + patLength; } for (int i = patIdxStart; i <= patIdxEnd; i++) { if (!patDirs.get(i).equals("**")) { patDirs = null; strDirs = null; return false; } } return true; } /** * Tests whether or not a string matches against a pattern. * The pattern may contain two special characters:<br> * '*' means zero or more characters<br> * '?' means one and only one character * * @param pattern The pattern to match against. * Must not be {@code null}. * @param str The string which must be matched against the pattern. * Must not be {@code null}. * @return <code>true</code> if the string matches against the pattern, * or <code>false</code> otherwise. */ public static boolean match(String pattern, String str) { return match(pattern, str, true); } /** * Tests whether or not a string matches against a pattern. * The pattern may contain two special characters:<br> * '*' means zero or more characters<br> * '?' means one and only one character * * @param pattern The pattern to match against. * Must not be {@code null}. * @param str The string which must be matched against the pattern. * Must not be {@code null}. * @param isCaseSensitive Whether or not matching should be performed * case sensitively. * @return <code>true</code> if the string matches against the pattern, * or <code>false</code> otherwise. */ public static boolean match(String pattern, String str, boolean isCaseSensitive) { char[] patArr = pattern.toCharArray(); char[] strArr = str.toCharArray(); int patIdxStart = 0; int patIdxEnd = patArr.length - 1; int strIdxStart = 0; int strIdxEnd = strArr.length - 1; char ch; boolean containsStar = false; for (char aPatArr : patArr) { if (aPatArr == '*') { containsStar = true; break; } } if (!containsStar) { // No '*'s, so we make a shortcut if (patIdxEnd != strIdxEnd) { return false; // Pattern and string do not have the same size } for (int i = 0; i <= patIdxEnd; i++) { ch = patArr[i]; if (ch != '?' && !equals(ch, strArr[i], isCaseSensitive)) { return false; // Character mismatch } } return true; // String matches against pattern } if (patIdxEnd == 0) { return true; // Pattern contains only '*', which matches anything } // Process characters before first star // CHECKSTYLE:OFF while ((ch = patArr[patIdxStart]) != '*' && strIdxStart <= strIdxEnd) { if (ch != '?' && !equals(ch, strArr[strIdxStart], isCaseSensitive)) { return false; // Character mismatch } patIdxStart++; strIdxStart++; } // CHECKSTYLE:ON if (strIdxStart > strIdxEnd) { // All characters in the string are used. Check if only '*'s are // left in the pattern. If so, we succeeded. Otherwise failure. for (int i = patIdxStart; i <= patIdxEnd; i++) { if (patArr[i] != '*') { return false; } } return true; } // Process characters after last star // CHECKSTYLE:OFF while ((ch = patArr[patIdxEnd]) != '*' && strIdxStart <= strIdxEnd) { if (ch != '?' && !equals(ch, strArr[strIdxEnd], isCaseSensitive)) { return false; // Character mismatch } patIdxEnd--; strIdxEnd--; } // CHECKSTYLE:ON if (strIdxStart > strIdxEnd) { // All characters in the string are used. Check if only '*'s are // left in the pattern. If so, we succeeded. Otherwise failure. for (int i = patIdxStart; i <= patIdxEnd; i++) { if (patArr[i] != '*') { return false; } } return true; } // process pattern between stars. padIdxStart and patIdxEnd point // always to a '*'. while (patIdxStart != patIdxEnd && strIdxStart <= strIdxEnd) { int patIdxTmp = -1; for (int i = patIdxStart + 1; i <= patIdxEnd; i++) { if (patArr[i] == '*') { patIdxTmp = i; break; } } if (patIdxTmp == patIdxStart + 1) { // Two stars next to each other, skip the first one. patIdxStart++; continue; } // Find the pattern between padIdxStart & padIdxTmp in str between // strIdxStart & strIdxEnd int patLength = patIdxTmp - patIdxStart - 1; int strLength = strIdxEnd - strIdxStart + 1; int foundIdx = -1; strLoop: for (int i = 0; i <= strLength - patLength; i++) { for (int j = 0; j < patLength; j++) { ch = patArr[patIdxStart + j + 1]; if (ch != '?' && !equals(ch, strArr[strIdxStart + i + j], isCaseSensitive)) { continue strLoop; } } foundIdx = strIdxStart + i; break; } if (foundIdx == -1) { return false; } patIdxStart = patIdxTmp; strIdxStart = foundIdx + patLength; } // All characters in the string are used. Check if only '*'s are left // in the pattern. If so, we succeeded. Otherwise failure. for (int i = patIdxStart; i <= patIdxEnd; i++) { if (patArr[i] != '*') { return false; } } return true; } /** * Tests whether two characters are equal. * @param c1 1st character * @param c2 2nd character * @param isCaseSensitive Whether to compare case sensitive * @return {@code true} if equal characters */ public static boolean equals(char c1, char c2, boolean isCaseSensitive) { if (c1 == c2) { return true; } if (!isCaseSensitive) { // NOTE: Try both upper case and lower case as done by String.equalsIgnoreCase() if (Character.toUpperCase(c1) == Character.toUpperCase(c2) || Character.toLowerCase(c1) == Character.toLowerCase(c2)) { return true; } } return false; } /** * Breaks a path up into a Vector of path elements, tokenizing on * <code>File.separator</code>. * * @param path Path to tokenize. Must not be {@code null}. * @return a List of path elements from the tokenized path */ public static List<String> tokenizePath(String path) { return tokenizePath(path, File.separator); } public static List<String> tokenizePath(String path, String separator) { List<String> ret = new ArrayList<>(); StringTokenizer st = new StringTokenizer(path, separator); while (st.hasMoreTokens()) { ret.add(st.nextToken()); } return ret; } /** * Normalizes the path by removing '.', '..' and double separators (e.g. '//') * * @param path Original path - ignored if {@code null}/empty * @param separator The separator used for the path components * @return normalized path */ public static String normalizePath(String path, String separator) { if (GenericUtils.isEmpty(path)) { return path; } boolean startsWithSeparator = path.startsWith(separator); List<String> tokens = tokenizePath(path, separator); int removedDots = 0; // clean up for (int i = tokens.size() - 1; i >= 0; i--) { String t = tokens.get(i); if (GenericUtils.isEmpty(t)) { tokens.remove(i); } else if (t.equals(".")) { tokens.remove(i); removedDots++; } else if (t.equals("..")) { tokens.remove(i); removedDots++; if (i >= 1) { tokens.remove(--i); removedDots++; } } } if (GenericUtils.isEmpty(tokens)) { if (removedDots > 0) { return ""; // had some "." and ".." after which we remained with no path } else { return separator; // it was all separators } } // serialize StringBuilder buffer = new StringBuilder(path.length()); for (int index = 0; index < tokens.size(); index++) { String token = tokens.get(index); if (index == 0) { if (startsWithSeparator) { buffer.append(separator); } else if (OsUtils.isWin32() && isWindowsDriveSpecified(token)) { buffer.append(separator); } } else { buffer.append(separator); } buffer.append(token); // for root Windows drive we need to return "C:/" or we get errors from the local file system if ((tokens.size() == 1) && OsUtils.isWin32() && isWindowsDriveSpecified(token)) { buffer.append(separator); } } return buffer.toString(); } /** * Converts a path to one matching the target file system by applying the * "slashification" rules, converting it to a local path and * then translating its separator to the target file system one (if different * than local one) * @param path The input path * @param pathSeparator The separator used to build the input path * @param fs The target {@link FileSystem} - may not be {@code null} * @return The transformed path * @see #translateToLocalFileSystemPath(String, char, String) */ public static String translateToLocalFileSystemPath(String path, char pathSeparator, FileSystem fs) { return translateToLocalFileSystemPath(path, pathSeparator, Objects.requireNonNull(fs, "No target file system").getSeparator()); } /** * Converts a path to one matching the target file system by applying the * "slashification" rules, converting it to a local path and * then translating its separator to the target file system one (if different * than local one) * @param path The input path * @param pathSeparator The separator used to build the input path * @param fsSeparator The target file system separator * @return The transformed path * @see #applySlashifyRules(String, char) * @see #translateToLocalPath(String) * @see #translateToFileSystemPath(String, String, String) */ public static String translateToLocalFileSystemPath(String path, char pathSeparator, String fsSeparator) { // In case double slashes and other patterns are used String slashified = applySlashifyRules(path, pathSeparator); // In case we are running on Windows String localPath = translateToLocalPath(slashified); return translateToFileSystemPath(localPath, File.separator, fsSeparator); } /** * Applies the "slashification" rules as specified in * <A HREF="http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap03.html#tag_03_266">Single Unix Specification version 3, section 3.266</A> * and <A HREF="http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap04.html#tag_04_11">section 4.11 - Pathname resolution</A> * @param path The original path - ignored if {@code null}/empty or does * not contain any slashes * @param sepChar The "slash" character * @return The effective path - may be same as input if no changes required */ public static String applySlashifyRules(String path, char sepChar) { if (GenericUtils.isEmpty(path)) { return path; } int curPos = path.indexOf(sepChar); if (curPos < 0) { return path; // no slashes to handle } int lastPos = 0; StringBuilder sb = null; while (curPos < path.length()) { curPos++; // skip the 1st '/' /* * As per Single Unix Specification version 3, section 3.266: * * Multiple successive slashes are considered to be the * same as one slash */ int nextPos = curPos; while ((nextPos < path.length()) && (path.charAt(nextPos) == sepChar)) { nextPos++; } /* * At this stage, nextPos is the first non-slash character after a * possibly 'seqLen' sequence of consecutive slashes. */ int seqLen = nextPos - curPos; if (seqLen > 0) { if (sb == null) { sb = new StringBuilder(path.length() - seqLen); } if (lastPos < curPos) { String clrText = path.substring(lastPos, curPos); sb.append(clrText); } lastPos = nextPos; } if (nextPos >= path.length()) { break; // no more data } curPos = path.indexOf(sepChar, nextPos); if (curPos < nextPos) { break; // no more slashes } } // check if any leftovers for the modified path if (sb != null) { if (lastPos < path.length()) { String clrText = path.substring(lastPos); sb.append(clrText); } path = sb.toString(); } /* * At this point we know for sure that 'path' contains only SINGLE * slashes. According to section 4.11 - Pathname resolution * * A pathname that contains at least one non-slash character * and that ends with one or more trailing slashes shall be * resolved as if a single dot character ( '.' ) were appended * to the pathname. */ if ((path.length() > 1) && (path.charAt(path.length() - 1) == sepChar)) { return path + "."; } else { return path; } } /** * Converts a possibly '/' separated path to a local path. <B>Note:</B> * takes special care of Windows drive paths - e.g., {@code C:} * by converting them to "C:\" * * @param path The original path - ignored if {@code null}/empty * @return The local path */ public static String translateToLocalPath(String path) { if (GenericUtils.isEmpty(path) || (File.separatorChar == '/')) { return path; } // This code is reached if we are running on Windows String localPath = path.replace('/', File.separatorChar); // check if '/c:' prefix if ((localPath.charAt(0) == File.separatorChar) && isWindowsDriveSpecified(localPath, 1, localPath.length() - 1)) { localPath = localPath.substring(1); } if (!isWindowsDriveSpecified(localPath)) { return localPath; // assume a relative path } /* * Here we know that we have at least a "C:" string - make sure it * is followed by the local file separator. Note: if all we have is * just the drive, we will create a "C:\" path since this is the * preferred Windows way to refer to root drives in the file system */ if (localPath.length() == 2) { return localPath + File.separator; // all we have is "C:" } else if (localPath.charAt(2) != File.separatorChar) { // be nice and add the missing file separator - C:foo => C:\foo return localPath.substring(0, 2) + File.separator + localPath.substring(2); } else { return localPath; } } public static boolean isWindowsDriveSpecified(CharSequence cs) { return isWindowsDriveSpecified(cs, 0, GenericUtils.length(cs)); } public static boolean isWindowsDriveSpecified(CharSequence cs, int offset, int len) { if ((len < 2) || (cs.charAt(offset + 1) != ':')) { return false; } char drive = cs.charAt(offset); return ((drive >= 'a') && (drive <= 'z')) || ((drive >= 'A') && (drive <= 'Z')); } /** * Converts a path containing a specific separator to one using the * specified file-system one * @param path The input path - ignored if {@code null}/empty * @param pathSeparator The separator used to build the input path - may not * be {@code null}/empty * @param fs The target {@link FileSystem} - may not be {@code null} * @return The path where the separator used to build it is replaced by * the file-system one (if different) * @see FileSystem#getSeparator() * @see #translateToFileSystemPath(String, String, String) */ public static String translateToFileSystemPath(String path, String pathSeparator, FileSystem fs) { return translateToFileSystemPath(path, pathSeparator, Objects.requireNonNull(fs, "No target file system").getSeparator()); } /** * Converts a path containing a specific separator to one using the * specified file-system one * @param path The input path - ignored if {@code null}/empty * @param pathSeparator The separator used to build the input path - may not * be {@code null}/empty * @param fsSeparator The target file system separator - may not be {@code null}/empty * @return The path where the separator used to build it is replaced by * the file-system one (if different) * @throws IllegalArgumentException if path or file-system separator are {@code null}/empty * or if the separators are different and the path contains the target * file-system separator as it would create an ambiguity */ public static String translateToFileSystemPath(String path, String pathSeparator, String fsSeparator) { ValidateUtils.checkNotNullAndNotEmpty(pathSeparator, "Missing path separator"); ValidateUtils.checkNotNullAndNotEmpty(fsSeparator, "Missing file-system separator"); if (GenericUtils.isEmpty(path) || Objects.equals(pathSeparator, fsSeparator)) { return path; } // make sure path does not contain the target separator if (path.contains(fsSeparator)) { ValidateUtils.throwIllegalArgumentException("File system replacement may yield ambiguous result for %s with separator=%s", path, fsSeparator); } // check most likely case if ((pathSeparator.length() == 1) && (fsSeparator.length() == 1)) { return path.replace(pathSeparator.charAt(0), fsSeparator.charAt(0)); } else { return path.replace(pathSeparator, fsSeparator); } } /** * Returns dependency information on these two files. If src has been * modified later than target, it returns true. If target doesn't exist, * it likewise returns true. Otherwise, target is newer than src and * is not out of date, thus the method returns false. It also returns * false if the src file doesn't even exist, since how could the * target then be out of date. * * @param src the original file * @param target the file being compared against * @param granularity the amount in seconds of slack we will give in * determining out of dateness * @return whether the target is out of date */ public static boolean isOutOfDate(File src, File target, int granularity) { if (!src.exists()) { return false; } if (!target.exists()) { return true; } return (src.lastModified() - granularity) > target.lastModified(); } /** * "Flattens" a string by removing all whitespace (space, tab, linefeed, * carriage return, and formfeed). This uses StringTokenizer and the * default set of tokens as documented in the single arguement constructor. * * @param input a String to remove all whitespace. * @return a String that has had all whitespace removed. */ public static String removeWhitespace(String input) { StringBuilder result = new StringBuilder(); if (input != null) { StringTokenizer st = new StringTokenizer(input); while (st.hasMoreTokens()) { result.append(st.nextToken()); } } return result.toString(); } }