PEAR Manual
Prev |  | Next

# Event_Dispatcher::addObserver()

Event_Dispatcher::addObserver() -- Add a new observer.

## Synopsis

    require_once 'Event/Dispatcher.php';

``void Event_Dispatcher::addObserver` (mixed $callback [, string $nName = EVENT_DISPATCHER_GLOBAL [, string $class = '']])`

## Description

Adds a new observer to the dispatcher.

Observers are PHP callbacks. That means you may either pass a function name as a string or an array containing an object or class and a method to call.

The callback is used as a signature for the observer, which allows you to remove it by passing the exact same parameters to removeObserver().

## Parameter

- mixed `$callback`

  Callback to notity, may either be a string containing the name of a global function or an array containing class or object and the name of the method to call.

- string `$nName = EVENT_DISPATCHER_GLOBAL`

  Acts as a filter: notify the observer only if the notification name matches the name passed in this parameter. Use `EVENT_DISPATCHER_GLOBAL` if the observer should be notified regardles of the notification name.

- string `$class = ''`

  Acts as a filter: notify the observer only if the sender of the notification matches the class passed in this parameter.

## Return value

void

## Note

This function can not be called statically.

Prev | Home | Next
Event_Dispatcher::getName() | Up | Event_Dispatcher::removeObserver()