Triggering content plugins in your extension
From Joomla! Documentation
Joomla!
3.x
A common example of using plugins is to run the content plugins on some text. This is useful if you want to support plugins that usually work on Content from a custom extension. For the content prepare trigger you can simply call:
$text = JHtml::_('content.prepare', $text);
For any other content triggers you must call:
$article = new stdClass;
$article->text = $text;
// add more to parameters if needed
$params = new JObject;
// Note JEventDispatcher succeeded the older JDispatcher from Joomla 1.5/2.5 however it does still work if you need to keep compatibility.
JPluginHelper::importPlugin('content');
$dispatcher = JEventDispatcher::getInstance();
$dispatcher->trigger('onContentPrepare', array('some.context', &$article, &$params, 0));
You might want to look at core components (for example com_content) for an example. See the triggers page for the possible content plugin triggers.