import java.util.EnumMap;

/**
 * Demo enum as array index and as a map key.
 */
public class EnumArrayDemo
{
    // constant compass directions
    enum Compass {north, east, south, west};
    // a name for each direction
    private String[] names = {"Noah", "Ernie", "Sally", "Wendy"};
    // a map for the names
    private EnumMap<Compass,String> namesMap = new EnumMap<Compass,String>(Compass.class);
    
    /** Show simple enum use */
    public void show()
    {
        // Iterate over all the compass directions
        for (Compass dir: Compass.values())
        {
            System.out.println(dir);
        }
        
        // This works, but is not recommended (may become deprecated)
        // Use one direction as an array index
        int index = Compass.east.ordinal();
        System.out.println(names[index]);
    }
    
    /** This is the preferred way use an enum value
        to lookup an associated value. */
    public void useMap()
    {
        namesMap.put(Compass.north, "Noah");
        namesMap.put(Compass.east, "Ernie");
        namesMap.put(Compass.south, "Sally");
        namesMap.put(Compass.west, "Wendy");
        
        System.out.println(namesMap.get(Compass.west));
        
    }

    /** a local test driver */
    public static void main(String[] args)
    {
        EnumArrayDemo app = new EnumArrayDemo();
        app.show();
        app.useMap();
    }
}