@SuppressWarnings("unchecked")
    public <T, E> RingbufferContainer<T, E> getContainerOrNull(int partitionId, ObjectNamespace namespace) {
        final Map<ObjectNamespace, RingbufferContainer> partitionContainers = containers.get(partitionId);
        return partitionContainers != null ? partitionContainers.get(namespace) : null;
    }
@ SuppressWarnings ( "unchecked" ) public < T , E > RingbufferContainer < T , E > getContainerOrNull ( int partitionId , ObjectNamespace namespace ) { final Map < ObjectNamespace , RingbufferContainer > partitionContainers = containers . get ( partitionId ) ; return partitionContainers != null ? partitionContainers . get ( namespace ) : null ; }
Returns the ringbuffer container if it already exists for the
given {@code partitionId} and {@code namespace}. Returns {@code null}
if it doesn't exist.

@param partitionId the partition ID of the ringbuffer container
@param namespace   the namespace of the ringbuffer container
@param <T>         the type of items in the ringbuffer container
@param <E>         the type of items in the ringbuffer
@return the ringbuffer container or {@code null} if it has not been created