Lazy Listeners

LazyListener

Zend\EventManager\LazyListener provides a callable wrapper around fetching a listener from a container and invoking it.

Usage

To create a LazyListener instance, you must pass to its constructor:

• a definition of the listener; this is an array defining:
  • a listener key, with the name of the listener service to pull from the container.
  • a method key, with the name of the method to invoke on the listener instance.
• a container; this is a container-interop, such as provided by zend-servicemanager, Aura.Di, etc.
• optionally an $env array; this is a set of options or other configuration to use when creating the listener instance. Since not all containers support passing additional options at creation, we recommend omitting the $env argument when creating portable applications.

As an example, let's assume:

• We have a listener registered in our container with the service name My\Application\Listener.
• The specific listener method is onDispatch.
• I have a container-interop instance in the variable $container and an event manager in the variable $events.

I might then create and attach my lazy listener as follows:

use My\Application\Listener;
use Zend\EventManager\LazyListener;

$events->attach('foo', new LazyListener([
    'listener' => Listener::class,
    'method'   => 'onDispatch',
], $container));

LazyListener implements the method __invoke(), allowing you to attach it directly as a callable listener!

Internally, it will do essentially the following:

$listener = $container->get($this->listener);
$method   = $this->method;
return $listener->{$method}($event);