No one can tell you Canon's plan, not even Canon until they are confirmed.
Looking at the 7D specifically, it was launched 2 1/2 years ago. If you look at the historical time between upgraded models there is usually about 2 years between them, with the 5D Mark III appearing 3 1/2 after the Mark II which is one of the longest periods.
Based on this, I would expect a follow up to the 7D within 12 months. While there is a possibility of a line being discontinued, it would be extremely unlikely for the 7D. It is Canon's only APS-C DSLR with a 100% coverage viewfinder or a weather-sealed body which all competitors have. The next level up, the full-frame 5D-class, is considerably more expensive and while it remains so, the need for a 7D-class camera is not going away.