code: /**
   * Copyright 2013 Alexey Ragozin
   *
   * 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 org.gridkit.jvmtool;
  
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /**
   * @author Alexey Ragozin (alexey.ragozin@gmail.com)
   */
  public class GlobHelper {
  
      /**
       * GLOB pattern supports *, ** and ? wild cards.
       * Leading and trailing ** have special meaning, consecutive separator become optional.
       */
      public static Pattern translate(String pattern, String separator) {
          StringBuffer sb = new StringBuffer();
          String es = escape(separator);
          // special starter
          Matcher ss = Pattern.compile("^([*][*][" + es + "]).*").matcher(pattern);
          if (ss.matches()) {
              pattern = pattern.substring(ss.group(1).length());
              // make leading sep optional
              sb.append("(.*[" + es + "])?");
          }
          // special trailer
          Matcher st = Pattern.compile(".*([" + es + "][*][*])$").matcher(pattern);
          boolean useSt = false;
          if (st.matches()) {
              pattern = pattern.substring(0, st.start(1));
              useSt = true;
          }
  
          for(int i = 0; i != pattern.length(); ++i) {
              char c = pattern.charAt(i);
              if (c == '?') {
                  sb.append("[^" + es + "]");
              }
              else if (c == '*') {
                  if (i + 1 < pattern.length() && pattern.charAt(i+1) == '*') {
                      i++;
                      // **
                      sb.append(".*");
                  }
                  else {
                      sb.append("[^" + es + "]*");
                  }
              }
              else {
                  if (c == '$') {
                      sb.append("\\$");
                  }
                  else if (Character.isJavaIdentifierPart(c) || Character.isWhitespace(c)) {
                      sb.append(c);
                  }
                  else {
                      sb.append('\\').append(c);
                  }
              }
          }
  
          if (useSt) {
              sb.append("([" + es + "].*)?");
          }
  
          return Pattern.compile(sb.toString());
      }
  
      private static String escape(String separator) {
          StringBuffer sb = new StringBuffer();
          for(int i = 0; i != separator.length(); ++i) {
              char c = separator.charAt(i);
              if ("\\[]&-".indexOf(c) >= 0){
                  sb.append('\\').append(c);
              }
              else {
                  sb.append(c);
              }
          }
          return sb.toString();
      }
  }
  