Caching Interface

[rudibatt]

There could be a Caching Interface that can be implemented by the integrator and is automatically used internally. By default it should be implemented by a dummy that does nothing.

• can be activated / deactivated
• add/contains/get entries (serialized)
• should not be used for timed-out results
• return the information about the cache size
• clearing cache (which should be triggered whenever there was a new import on FF side)
• cache-hit tracking