JAVA EE: Java Tutorial : What is a Class[State and Methods]?

Tuesday 11 August 2015

Java Tutorial : What is a Class[State and Methods]?

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Java Tutorial : What is a Class[State and Methods]?

Car.java

/**
 * Car class is the blueprint from which individual car objects are created.
 */
public class Car
{
    int gear = 1;
    int speed = 0;

    void changeGear(int newValue)
    {
        gear = newValue;
    }

    void speedUp(int increment)
    {
        speed = speed + increment;
    }

    void applyBrakes(int decrement)
    {
        speed = speed - decrement;
    }

    void printStates()
    {
        System.out.println( "gear:" + gear+" speed:" + speed );
    }

}

CarDemo.java

public class CarDemo
{
    public static void main(String[] args)
    {

        System.out
                .println("Change Maruthi Alto K10 Car gear to 2 and increase the speed to 100");

        Car maruthiAltok10 = new Car();

        maruthiAltok10.changeGear(2);
        maruthiAltok10.speedUp(100);

        maruthiAltok10.printStates();

        System.out.println("------------------------------");

        System.out
                .println("Change Swift Car gear to 3 and increase the speed to 200");

        Car swift = new Car();

        swift.changeGear(3);
        swift.speedUp(200);

        swift.printStates();

        System.out
        .println("Change Swift Car gear to 1 and apply break and decrease the speed from 200 to 150");
        
        swift.changeGear(1);
        swift.applyBrakes(50);

        swift.printStates();

    }
}

Output

Change Maruthi Alto K10 Car gear to 2 and increase the speed to 100
gear:2 speed:100
------------------------------
Change Swift Car gear to 3 and increase the speed to 200
gear:3 speed:200
Change Swift Car gear to 1 and apply break and decrease the speed from 200 to 150
gear:1 speed:150