Lazy Listeners

LazyEventListener

Zend\EventManager\LazyEventListener extends from LazyListener, but requires supplying the event name to which to attach, and optionally the priority, in the definition supplied at construction. This allows it to be a standalone instance that a listener aggregate can then query and use to attach to an event manager instance.

Usage

As noted in the introduction, the LazyEventListener is aware of two additional keys in the definition supplied at instantiation:

• event is the name of the event to which the lazy listener should attach.
• priority can optionally be provided to indicate the priority at which the lazy listener should attach.

As an example, let's assume:

• We have a listener registered in our container with the service name My\Application\Listener, and
• we want to use the method onDispatch when listening; further,
• we want to attach it to the event dispatch,
• at priority 100.

Additionally, we'll assume that we have a container-interop instance in the variable $container and an event manager in the variable $events.

You could create the lazy event listener as follows:

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

$listener = new LazyEventListener([
    'listener' => Listener::class,
    'method'   => 'onDispatch',
    'event'    => 'dispatch',
    'priority' => 100,
], $container);

Methods

LazyEventListener exposes two methods:

• getEvent() returns the event name used.
• getPriority($default = 1) returns either the priority passed at instantiation, or, if none was provided, the default passed when invoking the method.

Aggregates

The LazyEventListener features are primarily geared towards registering lazy listeners in aggregates. To that end, you will rarely instantiate or interact with them directly; instead, you'll leave that to the LazyListenerAggregate.