Enum Constant Inherited Methods

Java Tutorials - Herong's Tutorial Examples

∟Enum Constant Inherited Methods

This section provides a tutorial on how to invoke static and instance method inherited from the generic base class of java.lang.Enum.

From previous tutorial, we learned that all enum types have a common super type of java.lang.Enum<?> supported by the generic base class of java.lang.Enum<E extends Enum*lt;E>>. The base class implements 3 interfaces: Serializable, Comparable<E>, Constable. It also provided several interesting static and instance methods:

name() - Returning the name of this enum constant as specified in the declaration list.
ordinal() - Returning the ordinal (the position in the declaration list) of this enum constant.
toString() - Returning the name of this enum constant as specified in the declaration list.
compareTo() - Comparing this enum constant to another in the same enum type by their declaration position.
getDeclaringClass() - Returning the Class object of this enum constant.
valueOf() - Returning an enum constant of the specified enum type with the specified name.

Here is a sample program that shows you how to invoke methods listed above:

/* EnumInheritedMethods.java
 * Copyright (c) HerongYang.com. All Rights Reserved.
 */
import java.lang.Enum;
class EnumInheritedMethods {
   enum Rank {
      GOLD, SILVER, BRONZE;
   }

   public static void main(String[] arg) {
      java.io.PrintStream out = System.out;
      Rank gold = Rank.GOLD;
      Rank silver = Rank.SILVER;

      out.println("Inherited instance methods:");
      out.println("   silver.name() = "+silver.name());
      out.println("   silver.toString() = "+silver.toString());
      out.println("   silver.ordinal() = "+silver.ordinal());
      out.println("   silver.compareTo() = "+silver.compareTo(gold));
      out.println("   silver.getClass() = "+silver.getClass());
      out.println("   silver.getDeclaringClass() = "
         +silver.getDeclaringClass());

      out.println("Base static methods:");
      out.println("   Enum.valueOf() = "+Enum.valueOf(Rank.class, "GOLD"));
   }
}

If you compile and run EnumInheritedMethods.java, you should get:

herong> java EnumInheritedMethods.java

Inherited instance methods:
   silver.name() = SILVER
   silver.toString() = SILVER
   silver.ordinal() = 1
   silver.compareTo() = 1
   silver.getClass() = class EnumInheritedMethods$Rank
   silver.getDeclaringClass() = class EnumInheritedMethods$Rank
Base static methods:
   Enum.valueOf() = GOLD