question: public void destroy ( ) { context . removeVisualizationListener ( this ) ; context . removeResultListener ( this ) ; for ( Entry < VisualizationTask , Visualization > v : taskmap . entrySet ( ) ) { Visualization vis = v . getValue ( ) ; if ( vis != null ) { vis . destroy ( ) ; } } taskmap . clear ( ) ; }
target:  Cleanup function. To remove listeners.