Java Service to get File Extension

Is there any Flow service or a Java Service to get a file with particular extension from a set of files ??

http://techcommunity.softwareag.com/ecosystem/documentation/webmethods/wmsuite8_ga/Integration_Server_and_Process_Engine/8-0-SP1_Administering_Integration_Server.pdf page 108.

You can create a File port, and set a FileName Filter.