Programming Jakarta Struts, Second Edition

What Is a Business Object?

This question may sound a little too simplistic for a book on Struts. However, the term "business object” has many connotations, and some developers use it when they really mean something else. A business object (BO) is simply a software abstraction of a real-world entity. It represents a person, place, thing, or concept from the business domain. So, concepts such as items, orders, and customers are all business objects from the Storefront business domain.

Business objects consist of state and behavior. The OrderBO, for example, is aware of information relating to a single customer purchase order, including price, tax, and order status. An OrderBO also should know who the customer is and be able to provide this information. Having both state and behavior is an important criterion for a class to be considered a business object. Let’s examine a few other business object characteristics.

Requirements for Business Objects

For a class to be considered a business object, several conditions should be met:

• Consists of state and behavior

• Represents a person, place, thing, or concept from the business domain

• Is reusable

Business objects also can be grouped into different classifications. Generally, there are three types:

• Entity business object

• Process business object

• Event business object

Probably the most familiar, an entity BO represents a person, place, thing, or concept. These usually are extracted straight from the business domain by considering the nouns in the ...