content: package com.alan344.utils.tokenparse;
  
  /**
   * @author Clinton Begin
   */
  public class GenericTokenParser {
  
      private final String openToken;
      private final String closeToken;
  
      public GenericTokenParser(String openToken, String closeToken) {
          this.openToken = openToken;
          this.closeToken = closeToken;
      }
  
      public String parse(String text, TokenHandler handler) {
          if (text == null || text.isEmpty()) {
              return "";
          }
          // search open token
          int start = text.indexOf(openToken);
          if (start == -1) {
              return text;
          }
          char[] src = text.toCharArray();
          int offset = 0;
          final StringBuilder builder = new StringBuilder();
          StringBuilder expression = null;
          while (start > -1) {
              if (start > 0 && src[start - 1] == '\\') {
                  // this open token is escaped. remove the backslash and continue.
                  builder.append(src, offset, start - offset - 1).append(openToken);
                  offset = start + openToken.length();
              } else {
                  // found open token. let's search close token.
                  if (expression == null) {
                      expression = new StringBuilder();
                  } else {
                      expression.setLength(0);
                  }
                  builder.append(src, offset, start - offset);
                  offset = start + openToken.length();
                  int end = text.indexOf(closeToken, offset);
                  while (end > -1) {
                      if (end > offset && src[end - 1] == '\\') {
                          // this close token is escaped. remove the backslash and continue.
                          expression.append(src, offset, end - offset - 1).append(closeToken);
                          offset = end + closeToken.length();
                          end = text.indexOf(closeToken, offset);
                      } else {
                          expression.append(src, offset, end - offset);
                          break;
                      }
                  }
                  if (end == -1) {
                      // close token was not found.
                      builder.append(src, start, src.length - start);
                      offset = src.length;
                  } else {
                      builder.append(handler.handleToken(expression.toString()));
                      offset = end + closeToken.length();
                  }
              }
              start = text.indexOf(openToken, offset);
          }
          if (offset < src.length) {
              builder.append(src, offset, src.length - offset);
          }
          return builder.toString();
      }
  }
  