public void registerListener ( IPluginEventListener listener ) { if ( pluginEventListeners2 == null ) { pluginEventListeners2 = new ArrayList <> ( ) ; } if ( ! pluginEventListeners2 . contains ( listener ) ) { pluginEventListeners2 . add ( listener ) ; listener . onPluginEvent ( new PluginEvent ( this , PluginAction . SUBSCRIBE ) ) ; } }
Registers a listener for the IPluginEventListener callback event . If the listener has already been registered the request is ignored .