What is the likelihood of a near future attack from China?

When I was in high school the big scare was the Soviet Union. After the USSR crumbled the big threat my friends and I talked about was China. Now in 2015, have trade agreements decreased the chances of any imminent attack from China? Has that trade become strained lately? Is the threat actually more real than it was 25 years ago? Or do we have a sort of 'second cousin' relationship with China right now. How much of an ally are they with us? Or are they truly an ally at all?