Apple WebObjects 5 Manuale Utente Scaricare il pdf (Pagina 26)

26 What Is an Enterprise Object?

 Apple Computer, Inc. January 2002

CHAPTER 3

Enterprise Objects

In addition to providing classes that manage a set of enterprise-object instances in

memory, WebObjects defines an API to which enterprise objects must conform, as

well as default implementations for this API. As a result, you only need to

concentrate on the parts of your enterprise-object classes specific to your

application.

To maximize the reusability and extensibility of your objects, they shouldn’t embed

knowledge of the user interface or database alongside the business logic. For

example, if you embed knowledge of your user interface, you can’t reuse the objects

because each application’s user interface is different. Similarly, if you embed

knowledge of your database, you’ll have to update your objects every time you

modify the database’s schema.

If not in the business objects, then where does this knowledge go? It’s handled by

WebObjects as shown in Figure 3-1 (page 27).

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Apple WebObjects 5 Manuale Utente Pagina 26