[geeklog-devel] GL2 event model

[Tony Bibbs]

To fill in the blanks more I offer up the attached version.  Only 
difference is I show how the plugins are actually called.  Also, we 
might want to consider a 'priority' field for events that plugins listen 
to.  Using priorities would allow plugins to get called in some sort of 
priorty fashion.  I say that we come up with a standard set of 
priorities that plugins can use.  This make sense?

--Tony

Vincent Furia wrote:

>Here is what I had envisioned when I penned the Plugin API
>documentation.  It is a class that would be instantiated only once by
>GL2 core and available globally.  I prefer the per event registration
>as it will reduce the calls the "PluginEventHanlder" will have to make
>to listening plugins.
>
>-Vinny
>
>class PluginEventHandler {
>
>    /**
>    * Array containing event keys and listener (arrays as) values
>    * @access private
>    * @var array
>    */
>    private $listeners = array();
>
>    /**
>    * PluginEventHandler Constructor
>    *
>    * @access public
>    *
>    */
>    function __construct() {
>        // fetch registered listeners from database, populate $listeners
>    }
>
>    /**
>    * Register a plugin to listen for an event
>    *
>    * @access public
>    * @param  mixed   $event  event(s) to listen for (string or array)
>    * @param  string  $plugin plugin to be registered as listener
>    * @return boolean true on success
>    *
>    */
>    function registerListener($event, $plugin) {
>        // add the listener to the $listeners variable and the database
>    }
>
>    /**
>    * Unregister a plugin from listening for an event
>    *
>    * @access public
>    * @param  mixed   $event  event(s) to unregister (string or array)
>    * @param  string  $plugin plugin to be unregistered as listener
>    * @return boolean true on success
>    *
>    */
>    function unregisterListener($event, $plugin) {
>       // remove the listener for the specified events from $listeners
>       //   and the database.
>    }
>
>    /**
>    * Get all the listeners for a specific event
>    *
>    * @access public
>    * @param  string $event  event to get listeners of
>    * @return array  array of listeners to event $event
>    *
>    */
>    function getListeners($event) {
>       // remove the listener for the specified events from $listeners
>       //   and the database.
>    }
>
>    /**
>    * Notify all listeners that an event has occurred
>    *
>    * @access public
>    * @param  mixed $event  event requiring notification
>    * @param  mixed $vars   event specific variables
>    * @param  mixed $plugin NOTIFY_ALL, specific plugin, or array of plugins
>    * @return mixed event specific return values (or array of)
>    *
>    */
>    function notify($event, $vars, $plugin = NOTIFY_ALL) {
>
>    }
>
>}
>
>
>
>On Wed, 21 Jul 2004 22:10:55 +0000, Tom Willett <tomw at pigstye.net> wrote:
>  
>
>>Let me get this straight.
>>
>>GL2 Core would make the MySubjectObserverClass
>>
>>$obs = new MySubjectObserverClass;
>>
>>then the plugin would register by somehow getting the reference to the
>>MySubjectOvserverClass and register itself as a listener
>>
>>$obs->addListner($MyPlugin);
>>or
>>$obs->addListener($MyPlugin, $events);
>>etc
>>
>>Then when a event happened GL2 Core or a plugin could notify the plugins
>>
>>$obs->notifyAll($event)
>>
>>Do I have this about right?
>>
>>--
>>Tom Willett
>>tomw at pigstye.net
>>
>>
>>
>>---------- Original Message -----------
>>From: Tony Bibbs <tony at tonybibbs.com>
>>To: geeklog-devel at lists.geeklog.net
>>Sent: Wed, 21 Jul 2004 16:31:57 -0500
>>Subject: [geeklog-devel] GL2 event model
>>
>>    
>>
>>>The plugin API for GL2 that Vinny has drafted if surprisingly small
>>>because we are introducing an event based model.  Essentially, the GL2
>>>and all plugins have the option to register events that others can
>>>listen to.  To implement this I recommend an observer/observable design
>>>pattern similar to the example below.  A few things that need
>>>discussion.  First, the example below allows listening only at the
>>>object level.  The alternative is the force listening at the event level
>>>(in otherwords, addListener would take as a second arg an array of
>>>events the object listens to).  Any preference?  General questions?:
>>>
>>>class MySubjectObserverClass {
>>>   private $listeners = array();
>>>   private $listernerNextID  =  0;
>>>
>>>   // Alternative names: register, subscribe...
>>>   public function addListerner(&$obj)
>>>   {
>>>       $this->_listerners[] =& $obj;
>>>      return $this->listernerNextID++;
>>>   }
>>>
>>>   // Alternative name: unregister, unsubscribe...
>>>   public function removeListerner($id,'even't)
>>>   {
>>>        unset($this->listerners[$id]);
>>>   }
>>>
>>>   // Alternative name: broadcast...
>>>   public function notifyAll($event)
>>>   {
>>>       foreach ($this->listerners as $id => $obj)
>>>       {
>>>           $this->listerners[$id]->notify($event, $this);
>>>       }
>>>   }
>>>
>>>   // Alternative name: listen...
>>>   function notify($event, &$obj)
>>>   {
>>>        switch (get_class($obj)) {
>>>            case 'blah':
>>>               ...
>>>       }
>>>   }
>>>}
>>>
>>>_______________________________________________
>>>geeklog-devel mailing list
>>>geeklog-devel at lists.geeklog.net
>>>http://lists.geeklog.net/listinfo/geeklog-devel
>>>      
>>>
>>------- End of Original Message -------
>>
>>
>>
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>>
>>    
>>
>_______________________________________________
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>  
>
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