You cannot control the subscription lifetime directly.
As soon as the last client issues removeTable, an unsubscribe call is received by the Data Adapter.

If, however, a client just closes its connection (that is, it closes or refreshes the page) while a subscription is active,
then the session is kept alive for a few seconds and the subscription is also kept for this time.
This time can be configured through the <session_timeout_millis> configuration element.