code: public static CollisionConstraint imports(Xml node)
      {
          Check.notNull(node);
  
          final CollisionConstraint constraint = new CollisionConstraint();
  
          if (node.hasChild(NODE_CONSTRAINT))
          {
              for (final Xml current : node.getChildren(NODE_CONSTRAINT))
              {
                  final Orientation orientation = Orientation.valueOf(current.readString(ATT_ORIENTATION));
                  final String group = current.readString(ATT_GROUP);
                  constraint.add(orientation, group);
              }
          }
  
          return constraint;
      }
docs: Create the collision constraint data from node.
  
  @param node The node reference (must not be <code>null</code>).
  @return The collision constraint data.
  @throws LionEngineException If error when reading node.