com.javarush.task.task15.task1522

Earth.java

public class Earth implements Planet
{
    private static Earth instance;
    private Earth()
        {
        }
    public static Earth getInstance()
        {
        if (instance == null)
            instance = new Earth();
        return instance;
        }


}

Moon.java

public class Moon implements Planet
{
    private static Moon instance;
    private Moon()
        {
        }
    public static Moon getInstance()
        {
        if (instance == null)
            instance = new Moon();
        return instance;
        }


}

Planet.java

public interface Planet {
    static String SUN = "sun";
    static String MOON = "moon";
    static String EARTH = "earth";
}

Solution.java

/* 
Закрепляем Singleton pattern
*/

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

        }

    public static Planet thePlanet;

    //add static block here - добавьте статический блок тут
    static
        {

            //     Solution.
            try
                {
                    readKeyFromConsoleAndInitPlanet();
                }
            catch (IOException e)
                {
                    e.printStackTrace();
                }
        }

    public static void readKeyFromConsoleAndInitPlanet() throws IOException
        {
        // implement step #5 here - реализуйте задание №5 тут
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String         key    = reader.readLine();
        if (Planet.EARTH.contains(key))
            thePlanet=Earth.getInstance();
        else if (Planet.MOON.contains(key))
            thePlanet=Moon.getInstance();
        else if (Planet.SUN.contains(key))
            thePlanet=Sun.getInstance();
        else thePlanet=null;

        }
}

Sun.java

public class Sun implements Planet
{
    private static Sun instance;
    private Sun()
        {
        }
    public static Sun getInstance()
        {
        if (instance == null)
            instance = new Sun();
        return instance;
        }


}