public static function bootstrap() { //... BPubSub::i() // Usual syntax ->on('Originating_Class::method.specific', 'Callback_class::method') // Singleton instance method callback ->on('FCom_Catalog_Model_Product::afterSave', 'MyBootstrapClass.onProductSaveAfter') ; } public function onProductSaveAfter($args) { $product = $args['model']; // do something with $product model }