future-perfect progressive tense
There are six progressive tenses. Some grammarians refer to the progressive tense as the progressive aspect of a verb. The progressive tense shows an “ongoingness” of the action denoted by the verb.
The progressive tense is formed by using the verb to be as an auxiliary verb and adding the present participle (-ing) of the verb. Thus, the future-perfect progressive tense is formed by writing the future perfect of the verb to be (will have been) and adding the ‑ing verb. Thus:
He will have been studying this material for a long time.