final protected void setParent(PhysicsLink parent) {
        assert parent != null;
        assert this.parent == null;
        this.parent = parent;
        parent.children.add(this);
    }
Assign a parent/manager for this link.

@param parent (not null, alias created)
jme3-jbullet/src/main/java/com/jme3/bullet/animation/PhysicsLink.java