eventemitter

README

An EventEmitter for Go

Build Status:

Install

With go get:

% go get github.com/CHH/eventemitter

Usage

For more information please also see the Package Docs.

A new EventEmitter is created by the New function.

import "github.com/CHH/eventemitter"

func main() {
    emitter := eventemitter.New()
}

A listener is of type func (event *ee.Event) Listeners can be bound to event names with the On method:

emitter.On("foo", func(name string) {
    fmt.Printf("Hello World %s", name)
})

An event can be triggered by calling the Emit method:

<- emitter.Emit("foo", "John")

When Emit is called, each registered listener is called in its own Goroutine. They all share a common channel, which is returned by the Emit function.

var c chan interface{} 

c = emitter.Emit("foo", "John")

This channel can be used to wait until all listeners have finished, by using the <- operator without variable:

<- emitter.Emit("foo", "John")

Each listener yields a reference to eventemitter.Response on the channel once it has finished:

c := emitter.Emit("foo", "John")

for resp := <- c {
    // Do something
}

Embedding

EventEmitters can also be embedded in other types. When embedding you've to call the Init function on the EventEmitter, so the memory is correctly allocated:

type Server struct {
    eventemitter.EventEmitter
}

func NewServer() *Server {
    s := new(Server)

    // Allocates the EventEmitter's memory.
    s.EventEmitter.Init()

    // All functions of the EventEmitter are available:
    s.On("foo", func() {
        
    })
}

License

EventEmitter is distributed under the Terms of the MIT License. See the bundled file LICENSE.txt for more information.

Documentation

Index

• type EventEmitter
  • func New() *EventEmitter
  • func (self *EventEmitter) AddListener(event string, listener interface{})
  • func (self *EventEmitter) Emit(event string, argv ...interface{}) <-chan *Response
  • func (self *EventEmitter) Init()
  • func (self *EventEmitter) Listeners(event string) []reflect.Value
  • func (self *EventEmitter) On(event string, listener interface{})
  • func (self *EventEmitter) RemoveListeners(event string)
• type Response

Examples

• EventEmitter
• EventEmitter.Emit
• EventEmitter.Init

Types

type EventEmitter

type EventEmitter struct {
	// contains filtered or unexported fields
}

Example

// Construct a new EventEmitter instance
emitter := New()

emitter.On("hello", func() {
	fmt.Println("Hello World")
})

emitter.On("hello", func() {
	fmt.Println("Hello Hello World")
})

// Wait until all handlers have finished
<-emitter.Emit("hello")

Output:

Hello World
Hello Hello World

func New

func New() *EventEmitter

func (*EventEmitter) AddListener

func (self *EventEmitter) AddListener(event string, listener interface{})

AddListener adds an event listener on the given event name.

func (*EventEmitter) Emit

func (self *EventEmitter) Emit(event string, argv ...interface{}) <-chan *Response

Emits the given event. Puts all arguments following the event name into the Event's `Argv` member. Returns a channel if listeners were called, nil otherwise.

Example

emitter := New()

emitter.On("hello", func(name string) {
	fmt.Printf("Hello World %s\n", name)
})

<-emitter.Emit("hello", "John")

Output:

Hello World John

func (*EventEmitter) Init

func (self *EventEmitter) Init()

Allocates the EventEmitters memory. Has to be called when embedding an EventEmitter in another Type.

Example

package main

type SampleServer struct {
	EventEmitter
}

func NewServer() *Server {
	s := new(Server)

	// Initialize Maps
	s.EventEmitter.Init()
	return s
}

func main() {
	s := NewServer()

	// Do something

	s.Emit("connect" /*, conn */)
}

func (*EventEmitter) Listeners

func (self *EventEmitter) Listeners(event string) []reflect.Value

func (*EventEmitter) On

func (self *EventEmitter) On(event string, listener interface{})

Alias to AddListener.

func (*EventEmitter) RemoveListeners

func (self *EventEmitter) RemoveListeners(event string)

Removes all listeners from the given event.

type Response

type Response struct {
	// Name of the Event
	EventName string

	// Slice of all the handler's return values
	Ret []interface{}
}