In this example we shall show you how to have each enum instance represent a different sub-class. To make each enum instance represent a different sub-class one should perform the following steps:
- Create an
enumwith different enumconstants. - Give each
enumconstanta different behavior for some method. - Declare the method
abstractin theenumtype and override it with a concrete method in each constant. Such methods are known as constant-specific methods,
as described in the code snippet below.
// from http://download.oracle.com/javase/1,5.0/docs/guide/language/enums.html
public enum Operation {
PLUS { double eval(double x, double y) { return x + y; } },
MINUS { double eval(double x, double y) { return x - y; } },
TIMES { double eval(double x, double y) { return x * y; } },
DIVIDE { double eval(double x, double y) { return x / y; } };
// Do arithmetic op represented by this constant
abstract double eval(double x, double y);
}
Related Article:
Reference: Java Secret: Using an enum to build a State machine from our JCG partner Peter Lawrey at the Vanilla Java
This was an example of how to have each enum instance represent a different sub-class in Java.
