Down filtering

The write_results() method performs the work of communicating return results and out argument values to the client side. In the filter object framework, write_results() method handles additional responsibility of Down filtering. Here, we present algorithm used to carry out Down filtering.

Scenario: Down filtering

1. Perform Down filtering if method pass status is true.
   1. If current method has void return type, do nothing.
   2. If the invocation status is bad filter client invocation, do nothing.
   3. If there are no filters plugged to current object, do nothing.
   4. Else iterate through plugged filters in FIFO order till all filters are traversed. For every filter, create a filter request and copy the current invocation request's return value to it. Add the current invocation request's return value to the request as in argument. Finally, invoke the intercepted filter client method call using newly created filter request.
2. Communicate results of current invocation back to client side.
3. If current call is intercepted call at filter object, communicate method pass status to filter client.