Upfilter/Downfilter beta messages

Each filter object interface consists of upfilter and downfilter methods. upfilter methods filter corresponding client methods whereas downfilter methods filter return results. Multiple upfilter and downfilter methods can be associated with single client method. To provide this facility to every filter object, Filter, base class of each filter object, maintains mappings between client method and corresponding upfilter and downfilter methods. These mappings can be manipulated by sending upfilter or downfilter beta messages. Each beta message takes client method name and corresponding upfilter/downfilter method name as arguments. The filter object framework includes filterconf utility that facilitates sending these messages to filter objects. We now present the algorithm for sending and handling these messages which is implemented in the handle method of the corresponding classes.

Scenario: Sending Up/Down filter message

1. Create StaticAny objects representing client and filter method names.
2. Create StaticRequest object representing appropriate beta message.
3. Add the arguments and invoke the request.

Scenario: Handling Up/Down filter message

1. Create server side request and read the client and filter method names using it.
2. Check whether filter object already contains mapping corresponding to client method.
3. If yes, get the corresponding Up/Down filter methods and add the filter method name if it didn't exist already.
4. If no, create appropriate mapping in the filter object between received client and filter method.
5. Add the filter method name with disable status if it didn't exist already.