The definition of objects for use on the view tier is conceptually platform independent. A class is defined with a variable that provides access to its instance. Then there is a question of what scope the instance would live in.

The scopes are generally application, session, request and page, in the order of their width; application scope being the widest. This is however not universal. For component platforms that keep the page state, this would be kept across requests. Furthermore, there could be a conversation scope across multiple pages. Notwithstanding, the concepts here are relatively uniform across the platforms.