@Override public void init ( final ICommonContentExtensionSite config ) { final ITreeContentProvider contentProvider = config.getService ().getContentExtensionById ( this.contentExtensionId ).getContentProvider (); if ( contentProvider instanceof ObservableSetTreeContentProvider ) { addSource ( ( (ObservableSetTreeContentProvider)contentProvider ).getKnownElements () ); } else if ( contentProvider instanceof ObservableSetContentProvider ) { addSource ( ( (ObservableSetContentProvider)contentProvider ).getKnownElements () ); } else if ( contentProvider instanceof ObservableListContentProvider ) { addSource ( ( (ObservableListContentProvider)contentProvider ).getKnownElements () ); } else if ( contentProvider instanceof ObservableListTreeContentProvider ) { addSource ( ( (ObservableListTreeContentProvider)contentProvider ).getKnownElements () ); } }