Finds the class relevant for a given plugin.
array $plugin_id: The id of a plugin.
@return string The appropriate class name.
protected function getPluginClass($plugin_id) {
$plugin_definition = $this->discovery
->getDefinition($plugin_id);
if (empty($plugin_definition['class'])) {
throw new PluginException(sprintf('The plugin (%s) did not specify an instance class.', $plugin_id));
}
$class = $plugin_definition['class'];
if (!class_exists($class)) {
throw new PluginException(sprintf('Plugin (%s) instance class "%s" does not exist.', $plugin_id, $class));
}
return $class;
}