NHibernate:拦截器返回值的含义

我遇到了以下链接中描述的关于生成ID和级联的问题:

https://www.hibernate.org/hib_docs/nhibernate/html/example-parentchild.html

    public override bool OnLoad(object entity, object id, object[] state, string[] propertyNames, IType[] types)
    {
        if (entity is Persistent) ((Persistent)entity).OnLoad();
        return false;
    }

    public override bool OnSave(object entity, object id, object[] state, string[] propertyNames, IType[] types)
    {
        if (entity is Persistent) ((Persistent)entity).OnSave();
        return false;
    }

http://www.lostechies.com/blogs/rhouston/archive/2008/03/27/creating-a-timestamp-interceptor-in-nhibernate.aspx