question: @ Override public void actionPerform ( Component component ) { if ( beforeRefreshHandler != null ) { beforeRefreshHandler . run ( ) ; } CollectionDatasource datasource = owner . getDatasource ( ) ; Map < String , Object > params = getRefreshParams ( ) ; if ( params != null ) { datasource . refresh ( params ) ; } else { datasource . refresh ( ) ; } if ( afterRefreshHandler != null ) { afterRefreshHandler . run ( ) ; } }
target:  This method is invoked by action owner component. Don't override it, there are special methods to customize behaviour below.