package filter import "reflect" type Filter interface { Compare(Filter) bool Trigger(data interface{}) } type FilterEvent struct { filter Filter data interface{} } type Filters struct { id int watchers map[int]Filter ch chan FilterEvent quit chan struct{} } func New() *Filters { return &Filters{ ch: make(chan FilterEvent), watchers: make(map[int]Filter), quit: make(chan struct{}), } } func (self *Filters) Start() { go self.loop() } func (self *Filters) Stop() { close(self.quit) } func (self *Filters) Notify(filter Filter, data interface{}) { self.ch <- FilterEvent{filter, data} } func (self *Filters) Install(watcher Filter) int { self.watchers[self.id] = watcher self.id++ return self.id - 1 } func (self *Filters) Uninstall(id int) { delete(self.watchers, id) } func (self *Filters) loop() { out: for { select { case <-self.quit: break out case event := <-self.ch: for _, watcher := range self.watchers { if reflect.TypeOf(watcher) == reflect.TypeOf(event.filter) { if watcher.Compare(event.filter) { watcher.Trigger(event.data) } } } } } }