Violence in dreams is read symbolically, as conflict and strong feeling that has no calmer outlet yet. It speaks of anger, fear or tension held in waking life rather than of anything that is about to happen.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.