FUTURE PERFECT

Future perfect is a verb form that expresses action completed by a specified time in the future.

Subject + "will/be going to have" + Verb3 + Object

1. Completed Action before sth in The Future

    Example:

    a. By next November, I will have received my promotion.

    b. I am not going to have finished this test by 4 o'clock.

    c. Will she have learned enough English to communicate before she moves to Japanese.

    d. Sam is probably going to have completed the proposal by the time he leaves this afternoon.

    e. By the time I finish this course, I will have taken ten tests.

  

2. Duration before sth in The Future

    Example:

    a. I will have been in Qatar for six months by the time I leave.

    b. I will have been here for six months on June 25rd.

    c. By the time you read this I will have left.

    d. They will have completed the project before the deadline.

    e. By Friday, Sarah is going to have had my book for a week.


Source : Aplication 12 Tenses, English Grammar