class GenericTokenParser {

  public String parse(String text) {
    if (text == null || text.isEmpty()) {
      return "";
    }
    // 获取第一个openToken在SQL中的位置
    int start = text.indexOf(openToken, 0);
    // start为-1说明SQL中不存在任何参数占位符
    if (start == -1) {
      return text;
    }
    // 將SQL转换为char数组
    char[] src = text.toCharArray();
    // offset用于记录已解析的#{或者}的偏移量，避免重复解析
    int offset = 0;
    final StringBuilder builder = new StringBuilder();
    // expression为参数占位符中的内容
    StringBuilder expression = null;
    // 遍历获取所有参数占位符的内容，然后调用TokenHandler的handleToken（）方法替换参数占位符
    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);
            offset = end + closeToken.length();
            break;
          }
        }
        if (end == -1) {
          // close token was not found.
          builder.append(src, start, src.length - start);
          offset = src.length;
        } else {
          // 调用TokenHandler的handleToken（）方法替换参数占位符
          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();
  }

  public  GenericTokenParser(String openToken, String closeToken, TokenHandler handler);

}