import java.util.Arrays;
public class Main {
public void comparableExample() {
//Creating the objects that implements the Comparable interface
Car car1 = new Car("Toyota", 2006, 5000);
Car car2 = new Car("BMW", 2007, 5000);
Car car3 = new Car("Chrysler", 2007, 4000);
//Comparing the objects by calling the compareTo method on one of them
//passing another object as argument.
System.out.println("Car 1 equals Car 2: " + car1.compareTo(car2));
System.out.println("Car 1 equals Car 3: " + car1.compareTo(car3));
System.out.println("Car 2 equals Car 3: " + car2.compareTo(car3));
System.out.println();
//To sort them we create an array which is passed to the Arrays.sort()
//method.
Car[] carArray = new Car[] {car1, car2, car3};
Arrays.sort(carArray);
//Print out the sorted array
for (Car car : carArray)
System.out.println(car.toString());
}
//The Car class used to compare and sort objects.
class Car implements Comparable
{
private String make;
private int year;
private int mileage;
public Car(String make, int year, int mileage)
{
this.make = make;
this.year = year;
this.mileage = mileage;
}
//Mandatory method when implementing the
//Comparable interface. In this method we
//compare the mileage of the two car objects.
public int compareTo(Object obj)
{
if (obj instanceof Car)
{
Car car = (Car) obj;
if (this.mileage > car.getMileage())
return 1;
else if (this.mileage < car.getMileage())
return -1;
}
return 0;
}
public void setMake(String make)
{
this.make = make;
}
public void setYear(int year)
{
this.year = year;
}
public void setMileage(int mileage)
{
this.mileage = mileage;
}
public String getMake()
{
return make;
}
public int getYear()
{
return year;
}
public int getMileage()
{
return mileage;
}
public String toString()
{
StringBuffer buffer = new StringBuffer();
buffer.append("Make: " + make + "\n");
buffer.append("Year: " + year + "\n");
buffer.append("Mileage: " + mileage + "\n");
return buffer.toString();
}
}
public static void main(String[] args)
{
new Main().comparableExample();
}
}
