Since Lightstreamer Server 7.1 the Java In-Process Adapter SDK (SDK version 7.2.0) features the possibility to forcibly interrupt a client subscription from the Metadata Adapter.
This may be needed, for instance, when the authorization granted to a client for a subscription request is meant to be limited in time.
In practice, from Metadata Adapter code, after authorizing a subscription request from the notifyNewTables callback, you can keep the TableInfo object received; then, later, you can invoke forceUnsubscription on this object to close the subscription.
This behaves as though the unsubscription was requested by the client. The client is also notified of the unsubscription as though it had been requested by itself.

The following snippet of Metadata Adapter code exemplifies how you can enforce termination for a subscription that, for instance, has lasted for more than five minutes.

Note that implementing notifyNewTables to accept the subscription is a necessary preconditions. Hence implementing wantsTablesNotification and returning true is also necessary.

Also note that subscriptions are performed in "tables", i.e. groups of items for which the same field schema is specified.
As a consequence, enforced unsubscriptions are also performed on such tables as a whole, exactly like client unsubscription requests.
If enforced unsubscriptions with the scope of single items are needed in your application, ensure that the client subscribes to such items singularly (and check in notifyNewTables that this condition is met, by refusing any attempt to do otherwise).

As for the Remote Adapter SDKs, unfortunately, this feature is not available yet.