Question

i’m trying to figure with the best method to deal multiple class to a method that use a blocking resource.

The goal:

permit the multiple calls to a method that use a DataReader. While this first call is in progress, Keeping the rest to calls (if present) on hold until the method ends.

When the this method finish it’s execution, i need to discard every request accumuled while the first execution was in progress, only permitting that the last request execute.

In specific i’m dealing with repeated event firing in a Windows.Forms object that call a DataReader that doesn’t finish to execute and the next call that comes behind it raises an exception.

Any ideas to design this part ?

Answer 1

If request R1 is received and while it is being processed R2, R3 and R4 are received in that order then R2 and R3 should be discarded and R4 should be processed after R processing is finished.

The pseudo-code is something like the following:

receive request thread

if current_request is null
    assign to current_request
else
    assign to next_request

process request thread:

while true
    if current_request is not null
        process it
        set current_request = next_request, next_request = null

Changes to next_request and current_request should be done using the same lock.