Protein | Events

Event emitter-listener global class and behaviour trait

Install

---

composer require proteins/event

Require the global class via :

use Proteins\Event;

or the include the trait in your classes via :

use Proteins\Events;

class MyClass {
    use Events;
}

Attach an handler

---

You can attach an handler to a named event via the on method.

Event::on('my.event',function(){
   echo 'Hello, Friend!';
});

Multiple handlers can be attached to the event, they will be sequentially executed when the event will be triggered.

Event::on('my.event',function(){
   echo 'First!';
});

Event::on('my.event',function(){
   echo 'Second!';
});

You can attach handlers to any event name.

Trigger an event

---

You can trigger an event via the trigger method.

Event::trigger('my.event');

The trigger method will return an array containing the return values of all the handler attached to the event.

Example

Event::on('my.event',function(){
   return 'Hello!';
});

Event::on('my.event',function(){
   return time();
});

$results = Event::trigger('my.event');

The $results variable contains :

array(2) {
 [0]  =>  string(6) "Hello!"
 [1]  =>  int(1389115191)
}

NULL will be returned if no handlers are attached to the event.

You can run a trigger only one time with the triggerOnce method.

Passing parameters to event handlers

---

You can pass a variable number of parameter to event handlers appending them after the event name in the trigger method.

Event::on('eat',function($who,$what,$where){
   echo "$who ate a $what, in the $where.";
});

Event::trigger('eat','Simon','Burrito','Kitchen');

// Result : Simon ate a Burrito, in the Kitchen

Using the Events trait

---

You can augment any existing class adding the Events trait to them. The Events trait has the same identically signature of the standard Event module (in fact the Event Module is a simple wrapper of the Events trait).

class Game {
  use Events;
  public static function loadLevel($name){
    ...
    self::trigger("level.loaded", $name);
  }
}

Game::on("level.start",function($level_name){
  echo "Starting {$level_name}, BRING'EM'ON!!!\n";
});

Game::on("level.loaded",function($level_name){
  echo "Reticulating splines for {$level_name}...\n";
  Game::trigger("level.start", $level_name);
});

Game::on("level.start",function($level_name){
  echo "Replenish ammonitions...\n";
});

Game::loadLevel("E1M1");

Reticulating splines for E1M1...
Starting E1M1, BRING'EM'ON!!!
Replenish ammonitions...