question: @ Override public void cancelResourceRequest ( SamzaResourceRequest request ) { log . info ( "Cancelling request {} " , request ) ; synchronized ( lock ) { AMRMClient . ContainerRequest containerRequest = requestsMap . get ( request ) ; if ( containerRequest == null ) { log . info ( "Cancellation of {} already done. " , containerRequest ) ; return ; } requestsMap . remove ( request ) ; amClient . removeContainerRequest ( containerRequest ) ; } }
target:  Remove a previously submitted resource request. The previous container request may have been submitted. Even after the remove request, a Callback implementation must be prepared to receive an allocation for the previous request. This is merely a best effort cancellation.