question: @ SuppressWarnings ( "unchecked" ) public String register ( String channel , String scope , Serializable user ) { switch ( Scope . of ( scope , user ) ) { case APPLICATION : return register ( null , channel , APPLICATION_SCOPE , sessionScope , getViewScope ( false ) ) ; case SESSION : return register ( user , channel , sessionScope , APPLICATION_SCOPE , getViewScope ( false ) ) ; case VIEW : return register ( user , channel , getViewScope ( true ) , APPLICATION_SCOPE , sessionScope ) ; default : throw new UnsupportedOperationException ( ) ; } }
target:  Register given channel on given scope and returns the web socket channel identifier.