content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * Licensed 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 com.alibaba.nacos.common.utils;
  
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayDeque;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Deque;
  import java.util.Iterator;
  import java.util.List;
  import java.util.StringTokenizer;
  import java.util.regex.Pattern;
  
  /**
   * string util.
   *
   * @author Nacos
   * @author zzq
   */
  public class StringUtils {
      
      private StringUtils() {
      }
      
      public static final String DOT = ".";
      
      private static final int INDEX_NOT_FOUND = -1;
      
      public static final String COMMA = ",";
      
      public static final String EMPTY = "";
      
      public static final String LF = "\n";
      
      private static final String[] EMPTY_STRING_ARRAY = {};
      
      public static final String TOP_PATH = "..";
      
      public static final String FOLDER_SEPARATOR = "/";
      
      public static final String WINDOWS_FOLDER_SEPARATOR = "\\";
  
      public static final Pattern UUID_PATTERN = Pattern.compile(
              "^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$");
      
      /**
       * <p>Create a string with encoding format as utf8.</p>
       *
       * @param bytes the bytes that make up the string
       * @return created string
       */
      public static String newStringForUtf8(byte[] bytes) {
          return new String(bytes, StandardCharsets.UTF_8);
      }
      
      /**
       * <p>Checks if a string is  empty (""), null and  whitespace only.</p>
       *
       * @param cs the string to check
       * @return {@code true} if the string is empty and null and whitespace
       */
      public static boolean isBlank(final CharSequence cs) {
          int strLen;
          if (cs == null || (strLen = cs.length()) == 0) {
              return true;
          }
          for (int i = 0; i < strLen; i++) {
              if (!Character.isWhitespace(cs.charAt(i))) {
                  return false;
              }
          }
          return true;
      }
      
      /**
       * <p>Checks if a string is not empty (""), not null and not whitespace only.</p>
       *
       * @param str the string to check, may be null
       * @return {@code true} if the string is not empty and not null and not whitespace
       */
      public static boolean isNotBlank(String str) {
          return !isBlank(str);
      }
      
      /**
       * <p>Checks if a str is not empty ("") or not null.</p>
       *
       * @param str the str to check, may be null
       * @return {@code true} if the str is not empty or not null
       */
      public static boolean isNotEmpty(String str) {
          return !isEmpty(str);
      }
      
      /**
       * <p>Checks if a str is empty ("") or null.</p>
       *
       * @param str the str to check, may be null
       * @return {@code true} if the str is empty or null
       */
      public static boolean isEmpty(String str) {
          return str == null || str.length() == 0;
      }
      
      /**
       * <p>Returns either the passed in CharSequence, or if the CharSequence is
       * empty or {@code null}, the value of {@code defaultStr}.</p>
       *
       * @param str        the CharSequence to check, may be null
       * @param defaultStr the default CharSequence to return if the input is empty ("") or {@code null}, may be null
       * @return the passed in CharSequence, or the default
       */
      public static String defaultIfEmpty(String str, String defaultStr) {
          return isEmpty(str) ? defaultStr : str;
      }
      
      /**
       * <p>Returns either the passed in CharSequence, or if the CharSequence is
       * empty or {@code null} or whitespace only, the value of {@code defaultStr}.</p>
       *
       * @param str        the CharSequence to check, may be null, may be whitespace only
       * @param defaultStr the default CharSequence to return if the input is empty ("") or {@code null}, may be null
       * @return the passed in CharSequence, or the default
       */
      public static String defaultIfBlank(String str, String defaultStr) {
          return isBlank(str) ? defaultStr : str;
      }
      
      /**
       * <p>Returns either the passed in CharSequence, or if the CharSequence is
       * empty or {@code null} or whitespace only, the value of {@code EmptyString}.</p>
       *
       * @param str the CharSequence to check, may be null, may be whitespace only
       * @return the passed in CharSequence, or the empty string
       */
      public static String defaultEmptyIfBlank(String str) {
          return defaultIfBlank(str, EMPTY);
      }
      
      /**
       * <p>Compares two CharSequences, returning {@code true} if they represent
       * equal sequences of characters.</p>
       *
       * @param str1 the first string, may be {@code null}
       * @param str2 the second string, may be {@code null}
       * @return {@code true} if the string are equal (case-sensitive), or both {@code null}
       * @see Object#equals(Object)
       */
      public static boolean equals(String str1, String str2) {
          return str1 == null ? str2 == null : str1.equals(str2);
      }
      
      /**
       * <p>Removes control characters (char &lt;= 32) from both
       * ends of this String, handling {@code null} by returning {@code null}.</p>
       *
       * @param str the String to be trimmed, may be null
       * @return the trimmed string, {@code null} if null String input
       */
      public static String trim(final String str) {
          return str == null ? null : str.trim();
      }
      
      /**
       * Substring between two index.
       *
       * @param str   string
       * @param open  start index to sub
       * @param close end index to sub
       * @return substring
       */
      public static String substringBetween(String str, String open, String close) {
          if (str == null || open == null || close == null) {
              return null;
          }
          int start = str.indexOf(open);
          if (start != INDEX_NOT_FOUND) {
              int end = str.indexOf(close, start + open.length());
              if (end != INDEX_NOT_FOUND) {
                  return str.substring(start + open.length(), end);
              }
          }
          return null;
      }
      
      /**
       * <p>Joins the elements of the provided array into a single String
       * containing the provided list of elements.</p>
       *
       * @param collection the Collection of values to join together, may be null
       * @param separator  the separator string to use
       * @return the joined String, {@code null} if null array input
       */
      public static String join(Collection collection, String separator) {
          if (collection == null) {
              return null;
          }
          
          StringBuilder stringBuilder = new StringBuilder();
          Object[] objects = collection.toArray();
          
          for (int i = 0; i < collection.size(); i++) {
              if (objects[i] != null) {
                  stringBuilder.append(objects[i]);
                  if (i != collection.size() - 1 && separator != null) {
                      stringBuilder.append(separator);
                  }
              }
          }
          
          return stringBuilder.toString();
      }
      
      /**
       * Checks if CharSequence contains a search CharSequence irrespective of case, handling {@code null}.
       * Case-insensitivity is defined as by {@link String#equalsIgnoreCase(String)}.
       *
       * <p>A {@code null} CharSequence will return {@code false}.</p>
       *
       * @param str       the CharSequence to check, may be null
       * @param searchStr the CharSequence to find, may be null
       * @return true if the CharSequence contains the search CharSequence irrespective of case or false if not or {@code
       * null} string input
       */
      public static boolean containsIgnoreCase(final CharSequence str, final CharSequence searchStr) {
          if (str == null || searchStr == null) {
              return false;
          }
          String str1 = str.toString().toLowerCase();
          String str2 = searchStr.toString().toLowerCase();
          return str1.contains(str2);
      }
      
      /**
       * Checks if CharSequence contains a search CharSequence.
       *
       * @param str       the CharSequence to check, may be null
       * @param searchStr the CharSequence to find, may be null
       * @return true if the CharSequence contains the search CharSequence
       */
      public static boolean contains(final CharSequence str, final CharSequence searchStr) {
          if (str == null || searchStr == null) {
              return false;
          }
          return str.toString().contains(searchStr);
      }
      
      /**
       * <p>Checks if none of the CharSequences are blank ("") or null and whitespace only..</p>
       *
       * @param css the CharSequences to check, may be null or empty
       * @return {@code true} if none of the CharSequences are blank or null or whitespace only
       */
      public static boolean isNoneBlank(final CharSequence... css) {
          return !isAnyBlank(css);
      }
      
      /**
       * <p>Checks if any one of the CharSequences are blank ("") or null and not whitespace only..</p>
       *
       * @param css the CharSequences to check, may be null or empty
       * @return {@code true} if any of the CharSequences are blank or null or whitespace only
       */
      public static boolean isAnyBlank(final CharSequence... css) {
          if (ArrayUtils.isEmpty(css)) {
              return true;
          }
          for (final CharSequence cs : css) {
              if (isBlank(cs)) {
                  return true;
              }
          }
          return false;
      }
      
      /**
       * <p>Check if a CharSequence starts with a specified prefix.</p>
       *
       * <p>{@code null}s are handled without exceptions. Two {@code null}
       * references are considered to be equal. The comparison is case sensitive.</p>
       *
       * @param str    the CharSequence to check, may be null
       * @param prefix the prefix to find, may be null
       * @return {@code true} if the CharSequence starts with the prefix, case sensitive, or both {@code null}
       * @see java.lang.String#startsWith(String)
       */
      public static boolean startsWith(final CharSequence str, final CharSequence prefix) {
          return startsWith(str, prefix, false);
      }
      
      /**
       * <p>Check if a CharSequence starts with a specified prefix (optionally case insensitive).</p>
       *
       * @param str        the CharSequence to check, may be null
       * @param prefix     the prefix to find, may be null
       * @param ignoreCase indicates whether the compare should ignore case (case insensitive) or not.
       * @return {@code true} if the CharSequence starts with the prefix or both {@code null}
       * @see java.lang.String#startsWith(String)
       */
      private static boolean startsWith(final CharSequence str, final CharSequence prefix, final boolean ignoreCase) {
          if (str == null || prefix == null) {
              return str == null && prefix == null;
          }
          if (prefix.length() > str.length()) {
              return false;
          }
          if (ignoreCase) {
              String lowerCaseStr = str.toString().toLowerCase();
              String lowerCasePrefix = prefix.toString().toLowerCase();
              return lowerCaseStr.startsWith(lowerCasePrefix);
          } else {
              return str.toString().startsWith(prefix.toString());
          }
      }
      
      /**
       * <p>Case insensitive check if a CharSequence starts with a specified prefix.</p>
       *
       * <p>{@code null}s are handled without exceptions. Two {@code null}
       * references are considered to be equal. The comparison is case insensitive.</p>
       *
       * @param str    the CharSequence to check, may be null
       * @param prefix the prefix to find, may be null
       * @return {@code true} if the CharSequence starts with the prefix, case insensitive, or both {@code null}
       * @see java.lang.String#startsWith(String)
       */
      public static boolean startsWithIgnoreCase(final CharSequence str, final CharSequence prefix) {
          return startsWith(str, prefix, true);
      }
      
      /**
       * <p>Deletes all whitespaces from a String as defined by
       * {@link Character#isWhitespace(char)}.</p>
       *
       * @param str the String to delete whitespace from, may be null
       * @return the String without whitespaces, <code>null</code> if null String input
       */
      public static String deleteWhitespace(String str) {
          if (isEmpty(str)) {
              return str;
          }
          int sz = str.length();
          char[] chs = new char[sz];
          int count = 0;
          for (int i = 0; i < sz; i++) {
              if (!Character.isWhitespace(str.charAt(i))) {
                  chs[count++] = str.charAt(i);
              }
          }
          if (count == sz) {
              return str;
          }
          return new String(chs, 0, count);
      }
      
      /**
       * <p>Compares two CharSequences, returning {@code true} if they represent
       * equal sequences of characters, ignoring case.</p>
       *
       * @param str1 the first string, may be null
       * @param str2 the second string, may be null
       * @return {@code true} if the string are equal, case insensitive, or both {@code null}
       */
      public static boolean equalsIgnoreCase(String str1, String str2) {
          return str1 == null ? str2 == null : str1.equalsIgnoreCase(str2);
      }
      
      /**
       * Splits the provided text into an array with a maximum length, separators specified. If separatorChars is empty,
       * divide by blank.
       *
       * @param str the String to parse, may be null
       * @return an array of parsed Strings
       */
      @SuppressWarnings("checkstyle:WhitespaceAround")
      public static String[] split(final String str, String separatorChars) {
          if (str == null) {
              return null;
          }
          if (str.length() == 0) {
              return new String[0];
          }
          if (separatorChars == null) {
              separatorChars = " +";
          }
          return str.split(separatorChars);
      }
      
      /**
       * Tokenize the given {@code String} into a {@code String} array via a {@link StringTokenizer}.
       *
       * <p>The given {@code delimiters} string can consist of any number of
       * delimiter characters. Each of those characters can be used to separate tokens. A delimiter is always a single
       * character;
       *
       * @param str               the {@code String} to tokenize (potentially {@code null} or empty)
       * @param delimiters        the delimiter characters, assembled as a {@code String} (each of the characters is
       *                          individually considered as a delimiter)
       * @param trimTokens        trim the tokens via {@link String#trim()}
       * @param ignoreEmptyTokens omit empty tokens from the result array (only applies to tokens that are empty after
       *                          trimming; StringTokenizer will not consider subsequent delimiters as token in the first
       *                          place).
       * @return an array of the tokens
       * @see java.util.StringTokenizer
       * @see String#trim()
       */
      public static String[] tokenizeToStringArray(String str, String delimiters, boolean trimTokens,
              boolean ignoreEmptyTokens) {
          
          if (str == null) {
              return EMPTY_STRING_ARRAY;
          }
          
          StringTokenizer st = new StringTokenizer(str, delimiters);
          List<String> tokens = new ArrayList<>();
          while (st.hasMoreTokens()) {
              String token = st.nextToken();
              if (trimTokens) {
                  token = token.trim();
              }
              if (!ignoreEmptyTokens || token.length() > 0) {
                  tokens.add(token);
              }
          }
          return toStringArray(tokens);
      }
      
      /**
       * Copy the given {@link Collection} into a {@code String} array.
       *
       * <p>The {@code Collection} must contain {@code String} elements only.
       *
       * @param collection the {@code Collection} to copy (potentially {@code null} or empty)
       * @return the resulting {@code String} array
       */
      public static String[] toStringArray(Collection<String> collection) {
          return (!CollectionUtils.isEmpty(collection) ? collection.toArray(EMPTY_STRING_ARRAY) : EMPTY_STRING_ARRAY);
      }
      
      /**
       * Check whether the given {@code String} contains actual <em>text</em>.
       *
       * <p>More specifically, this method returns {@code true} if the
       * {@code String} is not {@code null}, its length is greater than 0, and it contains at least one non-whitespace
       * character.
       *
       * @param str the {@code String} to check (maybe {@code null})
       * @return {@code true} if the {@code String} is not {@code null}, its length is greater than 0, and it does not
       * contain whitespace only
       * @see Character#isWhitespace
       */
      public static boolean hasText(String str) {
          return (str != null && !str.isEmpty() && containsText(str));
      }
      
      private static boolean containsText(CharSequence str) {
          int strLen = str.length();
          for (int i = 0; i < strLen; i++) {
              if (!Character.isWhitespace(str.charAt(i))) {
                  return true;
              }
          }
          return false;
      }
      
      /**
       * Normalize the path by suppressing sequences like "path/.." and inner simple dots.
       *
       * <p>The result is convenient for path comparison. For other uses,
       * notice that Windows separators ("\") are replaced by simple slashes.
       *
       * <p><strong>NOTE</strong> that {@code cleanPath} should not be depended
       * upon in a security context. Other mechanisms should be used to prevent path-traversal issues.
       *
       * @param path the original path
       * @return the normalized path
       */
      public static String cleanPath(String path) {
          if (!hasLength(path)) {
              return path;
          }
          
          String normalizedPath = replace(path, WINDOWS_FOLDER_SEPARATOR, FOLDER_SEPARATOR);
          String pathToUse = normalizedPath;
          
          // Shortcut if there is no work to do
          if (pathToUse.indexOf(DOT) == -1) {
              return pathToUse;
          }
          
          // Strip prefix from path to analyze, to not treat it as part of the
          // first path element. This is necessary to correctly parse paths like
          // "file:core/../core/io/Resource.class", where the ".." should just
          // strip the first "core" directory while keeping the "file:" prefix.
          int prefixIndex = pathToUse.indexOf(':');
          String prefix = "";
          if (prefixIndex != -1) {
              prefix = pathToUse.substring(0, prefixIndex + 1);
              if (prefix.contains(FOLDER_SEPARATOR)) {
                  prefix = "";
              } else {
                  pathToUse = pathToUse.substring(prefixIndex + 1);
              }
          }
          if (pathToUse.startsWith(FOLDER_SEPARATOR)) {
              prefix = prefix + FOLDER_SEPARATOR;
              pathToUse = pathToUse.substring(1);
          }
          
          String[] pathArray = delimitedListToStringArray(pathToUse, FOLDER_SEPARATOR);
          // we never require more elements than pathArray and in the common case the same number
          Deque<String> pathElements = new ArrayDeque<>(pathArray.length);
          int tops = 0;
          
          for (int i = pathArray.length - 1; i >= 0; i--) {
              String element = pathArray[i];
              if (DOT.equals(element)) {
                  // Points to current directory - drop it.
              } else if (TOP_PATH.equals(element)) {
                  // Registering top path found.
                  tops++;
              } else {
                  if (tops > 0) {
                      // Merging path element with element corresponding to top path.
                      tops--;
                  } else {
                      // Normal path element found.
                      pathElements.addFirst(element);
                  }
              }
          }
          
          // All path elements stayed the same - shortcut
          if (pathArray.length == pathElements.size()) {
              return normalizedPath;
          }
          // Remaining top paths need to be retained.
          for (int i = 0; i < tops; i++) {
              pathElements.addFirst(TOP_PATH);
          }
          // If nothing else left, at least explicitly point to current path.
          if (pathElements.size() == 1 && pathElements.getLast().isEmpty() && !prefix.endsWith(FOLDER_SEPARATOR)) {
              pathElements.addFirst(DOT);
          }
          
          final String joined = collectionToDelimitedString(pathElements, FOLDER_SEPARATOR);
          // avoid string concatenation with empty prefix
          return prefix.isEmpty() ? joined : prefix + joined;
      }
      
      /**
       * Convert a {@code Collection} into a delimited {@code String} (e.g. CSV).
       *
       * <p>Useful for {@code toString()} implementations.
       *
       * @param coll  the {@code Collection} to convert (potentially {@code null} or empty)
       * @param delim the delimiter to use (typically a ",")
       * @return the delimited {@code String}
       */
      public static String collectionToDelimitedString(Collection<?> coll, String delim) {
          return collectionToDelimitedString(coll, delim, "", "");
      }
      
      /**
       * Convert a {@link Collection} to a delimited {@code String} (e.g. CSV).
       *
       * <p>Useful for {@code toString()} implementations.
       *
       * @param coll   the {@code Collection} to convert (potentially {@code null} or empty)
       * @param delim  the delimiter to use (typically a ",")
       * @param prefix the {@code String} to start each element with
       * @param suffix the {@code String} to end each element with
       * @return the delimited {@code String}
       */
      public static String collectionToDelimitedString(Collection<?> coll, String delim, String prefix, String suffix) {
          
          if (CollectionUtils.isEmpty(coll)) {
              return "";
          }
          
          int totalLength = coll.size() * (prefix.length() + suffix.length()) + (coll.size() - 1) * delim.length();
          for (Object element : coll) {
              totalLength += String.valueOf(element).length();
          }
          
          StringBuilder sb = new StringBuilder(totalLength);
          Iterator<?> it = coll.iterator();
          while (it.hasNext()) {
              sb.append(prefix).append(it.next()).append(suffix);
              if (it.hasNext()) {
                  sb.append(delim);
              }
          }
          return sb.toString();
      }
      
      /**
       * Check that the given {@code String} is neither {@code null} nor of length 0.
       *
       * <p>Note: this method returns {@code true} for a {@code String} that
       * purely consists of whitespace.
       *
       * @param str the {@code String} to check (maybe {@code null})
       * @return {@code true} if the {@code String} is not {@code null} and has length
       * @see #hasText(String)
       */
      public static boolean hasLength(String str) {
          return (str != null && !str.isEmpty());
      }
      
      /**
       * Take a {@code String} that is a delimited list and convert it into a {@code String} array.
       *
       * <p>A single {@code delimiter} may consist of more than one character,
       * but it will still be considered as a single delimiter string, rather than as a bunch of potential delimiter
       * characters, in contrast to {@link #tokenizeToStringArray}.
       *
       * @param str       the input {@code String} (potentially {@code null} or empty)
       * @param delimiter the delimiter between elements (this is a single delimiter, rather than a bunch individual
       *                  delimiter characters)
       * @return an array of the tokens in the list
       * @see #tokenizeToStringArray
       */
      public static String[] delimitedListToStringArray(String str, String delimiter) {
          return delimitedListToStringArray(str, delimiter, null);
      }
      
      /**
       * Take a {@code String} that is a delimited list and convert it into a {@code String} array.
       *
       * <p>A single {@code delimiter} may consist of more than one character,
       * but it will still be considered as a single delimiter string, rather than as a bunch of potential delimiter
       * characters, in contrast to {@link #tokenizeToStringArray}.
       *
       * @param str           the input {@code String} (potentially {@code null} or empty)
       * @param delimiter     the delimiter between elements (this is a single delimiter, rather than a bunch individual
       *                      delimiter characters)
       * @param charsToDelete a set of characters to delete; useful for deleting unwanted line breaks: e.g. "\r\n\f" will
       *                      delete all new lines and line feeds in a {@code String}
       * @return an array of the tokens in the list
       * @see #tokenizeToStringArray
       */
      public static String[] delimitedListToStringArray(String str, String delimiter, String charsToDelete) {
          
          if (str == null) {
              return EMPTY_STRING_ARRAY;
          }
          if (delimiter == null) {
              return new String[] {str};
          }
          
          List<String> result = new ArrayList<>();
          if (delimiter.isEmpty()) {
              for (int i = 0; i < str.length(); i++) {
                  result.add(deleteAny(str.substring(i, i + 1), charsToDelete));
              }
          } else {
              int pos = 0;
              int delPos;
              while ((delPos = str.indexOf(delimiter, pos)) != -1) {
                  result.add(deleteAny(str.substring(pos, delPos), charsToDelete));
                  pos = delPos + delimiter.length();
              }
              if (str.length() > 0 && pos <= str.length()) {
                  // Add rest of String, but not in case of empty input.
                  result.add(deleteAny(str.substring(pos), charsToDelete));
              }
          }
          return toStringArray(result);
      }
      
      /**
       * Delete any character in a given {@code String}.
       *
       * @param inString      the original {@code String}
       * @param charsToDelete a set of characters to delete. E.g. "az\n" will delete 'a's, 'z's and new lines.
       * @return the resulting {@code String}
       */
      public static String deleteAny(String inString, String charsToDelete) {
          if (!hasLength(inString) || !hasLength(charsToDelete)) {
              return inString;
          }
          
          int lastCharIndex = 0;
          char[] result = new char[inString.length()];
          for (int i = 0; i < inString.length(); i++) {
              char c = inString.charAt(i);
              if (charsToDelete.indexOf(c) == -1) {
                  result[lastCharIndex++] = c;
              }
          }
          if (lastCharIndex == inString.length()) {
              return inString;
          }
          return new String(result, 0, lastCharIndex);
      }
      
      /**
       * Replace all occurrences of a substring within a string with another string.
       *
       * @param inString   {@code String} to examine
       * @param oldPattern {@code String} to replace
       * @param newPattern {@code String} to insert
       * @return a {@code String} with the replacements
       */
      public static String replace(String inString, String oldPattern, String newPattern) {
          if (!hasLength(inString) || !hasLength(oldPattern) || newPattern == null) {
              return inString;
          }
          int index = inString.indexOf(oldPattern);
          if (index == -1) {
              // no occurrence -> can return input as-is
              return inString;
          }
          
          int capacity = inString.length();
          if (newPattern.length() > oldPattern.length()) {
              capacity += 16;
          }
          StringBuilder sb = new StringBuilder(capacity);
          
          int pos = 0;
          int patLen = oldPattern.length();
          while (index >= 0) {
              sb.append(inString, pos, index);
              sb.append(newPattern);
              pos = index + patLen;
              index = inString.indexOf(oldPattern, pos);
          }
          
          // append any characters to the right of a match
          sb.append(inString, pos, inString.length());
          return sb.toString();
      }
      
      /**
       * Apply the given relative path to the given Java resource path, assuming standard Java folder separation (i.e. "/"
       * separators).
       *
       * @param path         the path to start from (usually a full file path)
       * @param relativePath the relative path to apply (relative to the full file path above)
       * @return the full file path that results from applying the relative path
       */
      public static String applyRelativePath(String path, String relativePath) {
          int separatorIndex = path.lastIndexOf(FOLDER_SEPARATOR);
          if (separatorIndex != -1) {
              String newPath = path.substring(0, separatorIndex);
              if (!relativePath.startsWith(FOLDER_SEPARATOR)) {
                  newPath += FOLDER_SEPARATOR;
              }
              return newPath + relativePath;
          } else {
              return relativePath;
          }
      }
      
      /**
       * Extract the filename from the given Java resource path, e.g. {@code "myPath/myFile.txt" &rarr; "myFile.txt"}.
       *
       * @param path the file path (maybe {@code null})
       * @return the extracted filename, or {@code null} if none
       */
      
      public static String getFilename(String path) {
          if (path == null) {
              return null;
          }
          
          int separatorIndex = path.lastIndexOf(FOLDER_SEPARATOR);
          return (separatorIndex != -1 ? path.substring(separatorIndex + 1) : path);
      }
      
      /**
       * Capitalize a {@code String}, changing the first letter to upper case as per {@link Character#toUpperCase(char)}.
       * No other letters are changed.
       *
       * @param str the {@code String} to capitalize
       * @return the capitalized {@code String}
       */
      public static String capitalize(String str) {
          return changeFirstCharacterCase(str);
      }
      
      private static String changeFirstCharacterCase(String str) {
          if (!hasLength(str)) {
              return str;
          }
          
          char baseChar = str.charAt(0);
          char updatedChar;
          updatedChar = Character.toUpperCase(baseChar);
          if (baseChar == updatedChar) {
              return str;
          }
          
          char[] chars = str.toCharArray();
          chars[0] = updatedChar;
          return new String(chars);
      }
  
      public static boolean isUuidString(String str) {
          return UUID_PATTERN.matcher(str).matches();
      }
  }
  