Let’s review what we’ve covered so far, by building a food ordering app.
Before we start, decompose this specification:
You are developing a food ordering app. You need to track which food has been ordered, and the status of the order. The status of each order can be: PLACED, READY, ENROUTE, DELIVERED
Draw a UML class diagram with the classes you need. You can have an abstract food class, with different types of food extending the food super class.
Use of enum:
The type enum is actually a class.
For each option we can have arguments. Create a constructor (private by default) and a getter.
I wrote a setStatus(OrderStatus) method in my FoodOrder class to make sure the status setting makes sense
public void setStatus(OrderStatus status) {
if (this.status.getSequence() < status.getSequence())
this.status = status;
}This method could return a boolean to flag if the change in status was successful
We can set default methods like isReady() that returns false unless we overwrite the method in one of the options
public enum OrderStatus {
PLACED (1),
READY (2) {
public boolean isReady() {
return true;
}
},
ENROUTE (3),
DELIVERED (4);
int sequence;
OrderStatus(int sequence) {
this.sequence = sequence;
}
public int getSequence() {
return sequence;
}
public boolean isReady() {
return false;
}
}
} // enum OrderStatusWhat other classes and methods should you write to make this a complete application
We will build a GUI on top of this implementation in class