Merge remote-tracking branch 'origin/master'

src/main/java/net/minestom/server/utils/Direction.java

@@ -10,4 +10,23 @@ public enum Direction {
 
     public static final Direction[] HORIZONTAL = { SOUTH, WEST, NORTH, EAST };
 
+    public Direction opposite() {
+        switch (this) {
+            case UP:
+                return DOWN;
+            case DOWN:
+                return UP;
+            case EAST:
+                return WEST;
+            case WEST:
+                return EAST;
+            case NORTH:
+                return SOUTH;
+            case SOUTH:
+                return NORTH;
+
+            default:
+                throw new IllegalArgumentException();
+        }
+    }
 }