You will find yourself using objects that are common in business to build an object-oriented business system. Let s take a look at a supermarket to get a better understanding of a business system and the objects used in business (see Figure 1-2). You ve visited plenty of supermarkets, so you probably have a general idea of how a supermarket receives merchandise from a warehouse.
Each week supermarket employees survey the shelves and the storeroom to determine what products to order from the supermarket s central warehouse. They place information about each product and the quantity to order on an order form, which then is sent to the warehouse for fulfillment.
At the warehouse, information on the order form is transferred to a pick list used by warehouse employees while going through the warehouse picking products to fill the order. Products are listed on a packing slip and then placed in cartons. A packing slip lists all the products contained in the carton and their quantities . A shipping label is placed on a carton, and a shipping order is written. The shipping order has instructions on where the cartons are to be delivered. A trucker then uses the shipping order to deliver the carton to the supermarket.
Employees in the supermarket read the label on each carton to be sure that the carton is addressed to them. They open the carton and read the packing slip. Items on the packing slip are compared to items in the carton. Any discrepancies are noted and reported to the warehouse in a memo. Items are then removed from the carton and placed on supermarket shelves.
There are many objects in the system a supermarket uses to order merchandise to restock shelves. These include an employee, a building, cartons, and a truck. However, we are interested in objects of the system, such as the form used to order merchandise.
What business objects do you see in the supermarket ordering system? Time s up! Compare your list of objects to this list:
Each object has attributes and behaviors. Attributes include the product number, product name, and quantity, which are found in each of these objects, except for the shipping label. Attributes of the shipping label object include the name and address of the supermarket and the name and address of the shipper.
Many objects used in business are forms that someone fills out, such as an order form. It is hard to imagine an object having a behavior because it doesn t do anything. It is not like a window that opens and closes .
However, an object does have behaviors. Here are a few behaviors of an order form object:
Delete modified information
Display the form
Process the order
Modify the order
Cancel the order