code: public String find(PushbackReader in, int size) throws IOException, SyntaxErrorException
      {
          if (acceptEmpty)
          {
              throw new IllegalArgumentException("using find for  '" + expression + "'  that accepts empty string");
          }
          InputReader reader = Input.getInstance(in, size);
          int rc = find(reader);
          reader.release();
          if (rc == 1)
          {
              return reader.getString();
          }
          else
          {
              throw new SyntaxErrorException("string matching  '" + expression + "'  not found");
          }
      }
docs: Finds next match and returns the matched string
  @param in
  @param size
  @return Matched string
  @throws IOException
  @throws SyntaxErrorException