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Java Tutorial : What is an Interface (Bike)

Java Tutorial : What is an Interface (Bike)

Java Tutorial : What is an Interface (Bike)

Bike.java

/**
 * An interface is a group of related methods with empty bodies.
 */
public interface Bike
{
    void changeGear(int newValue);

    void speedUp(int increment);

    void applyBrakes(int decrement);
}

/**
 * 
 * To implement Bike interface, the name of your class would change (to a
 * particular brand of Bike, for example, such as SportBike)
 *
 */

public class SportBike implements Bike
{

    int speed = 0;
    int gear = 1;

    /*
     * The compiler will now require that methods changeGear, speedUp, and
     * applyBrakes all be implemented. Compilation will fail if those methods
     * are missing from this class.
     */

    @Override
    public void changeGear(int newValue)
    {
        gear = newValue;

    }

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

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

    public void printStates()
    {
        System.out
                .println("SportBike [speed=" + speed + ", gear=" + gear + "]");
    }

}