Java 11 and 12 – New Features

Using inheritance with enum constants

The following is another example of an enum, that works with a set of subclasses by passing instances of subclasses to the enum constructor. To get the point across, I've modified the Size enum, which we have been working on with since the beginning of this chapter. The following is the modified code:

class Measurement {}                      // base class 
class Small extends Measurement {         // derived class 
    String text = "Small";                // state specific to class                                           //Small 
} 
class Medium extends Measurement {        // derived class 
    public int getLength() {              // behavior specific to class                                           //Medium 
        return 9999; 
    } 
} 
class Large extends Measurement {}        // derived class 
 
enum Size {                                
    SMALL(new Small()),                // constant created using Small  //instance ...