GetFilter() Method used in C++

[venujune6]

Hi,
I have an application running on Platforms Microsoft Windows Server 2003, which uses a method called GetFilter(). I tried to look over MSDN, it says
"The GetFilter method of the IProtocolHandle rSite interface retrieves the appropriate IFilter based on the parameters supplied. "

Could anyone please advice what is the meaning of "IFilter" here ?
Part of my code is pasted below, it may help for analysis :
Please advice what does this GetFirstPage() method does ?
=============== =============== =============== =======
/*Set the Sort Order first on TP ID followed by Buy Currency and then the
Sell Currency*/
pFilterItem = 0;
pFilterItem =
(*pMAPYCLSCPGHa ndler)->GetFilter()->GetFilterItemB yProperty(CLSFT PId);
pFilterItem->SetSortOrder(A scending);
pFilterItem = 0;
pFilterItem =
(*pMAPYCLSCPGHa ndler)->GetFilter()->GetFilterItemB yProperty(CLSFB uyCurrencyId);
pFilterItem->SetSortOrder(A scending);
pFilterItem = 0;
pFilterItem =
(*pMAPYCLSCPGHa ndler)->GetFilter()->GetFilterItemB yProperty(CLSFS ellCurrencyId);
pFilterItem->SetSortOrder(A scending);

/*Request the one and only available page */
(*pMAPYCLSCPGHa ndler)->GetFirstPage() ;


=============== =============== =============== =======

[weaknessforcats]

Does this help: http://www.codeproject .com/KB/cs/fulltextsearchi ngifinters.aspx p.