this is java and I need help to write "Display an appropriate message if the fuel efficiency should not be calculated." in the override method in Car file.

Please read carefully.

Class: Vehicle

• Create an abstract class based on the following Unified Modeling Language Class Diagram.
• In the default constructor set Range to -1, and Capacity to -1.
• Abstract method Fuel Efficiency.

  Vehicle

  • range: double (units: miles)
  • capacity: double (units: gallons)
  • Vehicle()
  • Vehicle(range: double, capacity: double)

  • setRange(double): void
  • getRange(): double
  • setCapacity(double): void
  • getCapacity(): double
  • fuelEfficiency(): double

Class: Car (subclass of Vehicle, implementation of Comparable)

• Create a class based on the following Unified Modeling Language Class Diagram.
• In the default constructor set Airbags to 1, Convertible to false.
• Calculate the Fuel Efficiency using this formula (range / capacity). Overriding Abstract Methods. Display an appropriate message if the fuel efficiency should not be calculated.
• Compare To should return 100 if the fuel efficiency of object is smaller, 0 if the fuel efficiency is equal, -100 if the fuel efficiency is larger.

  Car

  • airbags: int
  • convertible: boolean
  • Car()
  • Car(airbags: int, convertible: boolean)
  • Car(airbags: int, convertible: boolean, range: double, capacity: double)

  • setAirbags(airbags: int): void
  • getAirbags(): int
  • setConvertible(convertible: boolean): void
  • getConvertible(): boolean
  • fuelEfficiency():double
  • compareTo(object: Car): int

here is my Vehicle file

public abstract class Vehicle { // VARIABLES private double range; // miles private double capacity; // gallons

// CONSTRUCTORS protected Vehicle() { this.range = -1; this.capacity = -1; } protected Vehicle(double range, double capacity) { this.range = range; this. capacity = capacity; } // METHODS public void setRange(double range) { this.range = range; } public double getRange() { return(this.range); } public void setCapacity(double capacity) { this.capacity = capacity; } public double getCapacity() { return(this.capacity); } public abstract double fuelEfficiency(); }

--------------------------------------------------------------------------------------------------

here is my Car file

public class Car extends Vehicle implements Comparable { // VARIALBES int airbags; boolean convertible; // CONTRUCTORS public Car() { this.airbags = 1; this.convertible = false; } public Car(int airbags, boolean convertible) { this.airbags = airbags; this.convertible = convertible; } public Car(int airbags, boolean convertible, double range, double capacity) { super(range, capacity); this.airbags = airbags; this.convertible = convertible; } // METHODS public void setAirbags(int airbags) { this.airbags = airbags; } public int getAirbags() { return (this.airbags); } public void setConvertible(boolean convertible) { this.convertible = convertible; } public boolean getConvertible() { return (this.convertible); } @Override public double fuelEfficiency() { return(super.getRange() / super.getCapacity()); } @Override public int compareTo(Car object) { if (this.fuelEfficiency() > object.fuelEfficiency()) { return 100; } else if (this.fuelEfficiency() < object.fuelEfficiency()) { return -100; } else { return 0; } }