diff --git a/event/event.go b/event/event.go index 74f8043da..09759ee50 100644 --- a/event/event.go +++ b/event/event.go @@ -7,8 +7,16 @@ import ( "sync" ) +// Subscription is implemented by event subscriptions. type Subscription interface { + // Chan returns a channel that carries events. + // Implementations should return the same channel + // for any subsequent calls to Chan. Chan() <-chan interface{} + + // Unsubscribe stops delivery of events to a subscription. + // The event channel is closed. + // Unsubscribe can be called more than once. Unsubscribe() } @@ -21,6 +29,7 @@ type TypeMux struct { stopped bool } +// ErrMuxClosed is returned when Posting on a closed TypeMux. var ErrMuxClosed = errors.New("event: mux closed") // NewTypeMux creates a running mux. diff --git a/event/example_test.go b/event/example_test.go new file mode 100644 index 000000000..2f47f6f27 --- /dev/null +++ b/event/example_test.go @@ -0,0 +1,42 @@ +package event + +import "fmt" + +func ExampleTypeMux() { + type someEvent struct{ I int } + type otherEvent struct{ S string } + type yetAnotherEvent struct{ X, Y int } + + var mux TypeMux + + // Start a subscriber. + done := make(chan struct{}) + sub := mux.Subscribe(someEvent{}, otherEvent{}) + go func() { + for event := range sub.Chan() { + fmt.Printf("Received: %#v\n", event) + } + fmt.Println("done") + close(done) + }() + + // Post some events. + mux.Post(someEvent{5}) + mux.Post(yetAnotherEvent{X: 3, Y: 4}) + mux.Post(someEvent{6}) + mux.Post(otherEvent{"whoa"}) + + // Stop closes all subscription channels. + // The subscriber goroutine will print "done" + // and exit. + mux.Stop() + + // Wait for subscriber to return. + <-done + + // Output: + // Received: event.someEvent{I:5} + // Received: event.someEvent{I:6} + // Received: event.otherEvent{S:"whoa"} + // done +}