Creating an event simply sets a callback to be invoked if and only if during the execution of the current program such an event is triggered. This is useful if you require notification of certain actions throughout your application.

Registering an Event

Registering an event will allow your callback to be notified when such an event is triggered. Any controller or model that inherits from AppController or AppModel will already have access to the event handler and can immediately begin registering events.

$this->Events->register("EventName", array($this, "callbackMethod"));

In the above example, when the "EventName" event is triggered the "callbackMethod" will be invoked on the object that registered the event. If you're working from a separate location that doesn't inherit from AppController or AppModel, you can load the Event handler manually.

// Load the Event handler
Loader::load(COMPONENTDIR . "events" . DS . "events.php");
$this->Events = new Events();

Triggering an Event

Triggering an event invokes all callbacks that have been registered for that event. To trigger the "EventName" event invoke the Events::trigger() method and pass in any parameters that you want each of the callbacks to receive.

$this->Events->trigger("EventName", array("square", "pink"));

Here's a complete example that will output "square pink".

<?php
class MyController extends AppController {

    public function index() {
        $this->Events->register("EventName", array($this, "callbackMethod"));
        $this->Events->trigger("EventName", array("square", "pink"));
        return false; // don't render a view
    }

    public function callbackMethod($shape, $color) {
        echo $shape . " " . $color;
    }
}
?>