Chapter 36: Enum Map

Java EnumMap class is the specialized Map implementation for enum keys. It inherits Enum and AbstractMap classes.

the Parameters for java.util.EnumMap class.

K: It is the type of keys maintained by this map. V: It is the type of mapped values.

Section 36.1: Enum Map Book Example

import java.util.*;

class Book {

int id;

String name,author,publisher;

int quantity;

public Book(int id, String name, String author, String publisher, int quantity) {

this.id =  id; this.name  

=  name; this.author =

author;

this.publisher  =  publisher;

this.quantity  =  quantity;

}

}

public class EnumMapExample {

// Creating enum

public enum Key{

One, Two,  Three

};

public  static  void  main(String[]  args)  {

EnumMap<Key,  Book>  map  =  new  EnumMap<Key,  Book>(Key.class);

// Creating Books

Book  b1=new  Book(101,”Let  us  C”,”Yashwant  Kanetkar”,”BPB”,8);

Book  b2=new  Book(102,”Data  Communications  &  Networking”,”Forouzan”,”Mc  Graw  Hill”,4); Book  

b3=new  Book(103,”Operating  System”,”Galvin”,”Wiley”,6);

// Adding Books to Map

map.put(Key.One,  b1);

map.put(Key.Two,  b2);

map.put(Key.Three,  b3);

// Traversing EnumMap

for(Map.Entry<Key,  Book>  entry:map.entrySet()){

Book  b=entry.getValue();

System.out.println(b.id+”  “+b.name+”  “+b.author+”  “+b.publisher+”  “+b.quantity);

}

}

}