Question $4$:

UPM Cooperative shop $($KUPUTRA$)$ has an inventory management system.

Inventory is a class that consists of integer variables, namely itemID and

itemType, and a String variable namely itemName which can only be accessed

through setter and getter methods.

Variable itemType represents the types of inventories which are either $1$ for sales or

$2$ for rental. Inventory also contains a static integer variable, namely count which

will update the total Inventory objects created. The creation of an Inventory object

needs two data which are itemType and itemName.

$($i$)$ Draw the UML class diagram for the Inventory class.

$($ii$)$ Modify the Inventory class in $($i$)$ so that the types of inventories will instead

become the subclasses of Inventory. Draw the UML class diagram showing the

relationships between those classes.

$($iii$)$ Draw a UML class diagram that shows the relationships among the Customer,

Staff, Transaction, and Inventory classes. A Customer can rent one or more

inventories in a transaction if authorized by a KUPUTRA staff of the store.