question: private long findHoverEntry ( Point p ) { double smallestDistance = HOVER_RADIUS ; long foundHoverEntry = - 1 ; for ( Point point : locations . keySet ( ) ) { double distance = p . distance ( point ) ; if ( distance < HOVER_RADIUS ) { if ( distance < smallestDistance ) { foundHoverEntry = locations . get ( point ) ; smallestDistance = distance ; } } } return foundHoverEntry ; }
target:  Finds the key (time) of the currently hovered entry, or -1 if none is hovered.