This class supports decoding of a string containing logical operators (e.g. | or &) and parentheses to make it easier to manipulate the substrings (keywords) relevant to a database search. In other terms, this class is useful to execute archive searches on the base of formatted strings input by the user in a HTML form. The search class is only used to prepare the string and can not be directly used to execute a database search. To do this, the search string supplied by the user must be first translated into an SQL string of equivalent meaning using the search class.