Java Program to Implement EnumMap API

// Java program to implement enum Map API

import java.lang.*;
import java.util.Collection;
import java.util.EnumMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

public class EnumMapImpl<K extends Enum<K>, V> {
    EnumMap<K, V> enumMap;

    // For creating an empty enum map with the specified key
    // type.
    public EnumMapImpl(Class<K> keyType)
    {
        enumMap = new EnumMap<K, V>(keyType);
    }

    // For creating an enum map which will have the same key
    // type as the specified enum map,

    public EnumMapImpl(EnumMap<K, ? extends V> m)
    {
        enumMap = new EnumMap<K, V>(m);
    }

    // For Creating an enum map that is initialized from the
    // specified map.
    public EnumMapImpl(Map<K, ? extends V> m)
    {
        enumMap = new EnumMap<K, V>(m);
    }

    // Clears the Mappings from the enumMap.
    public void clear() { enumMap.clear(); }
  
    // Returns true if the specified value is found.
    public boolean containsValue(Object value)
    {
        return enumMap.containsValue(value);
    }

    // Returns true if the specified key is found.
    public boolean containsKey(Object key)
    {
        return enumMap.containsKey(key);
    }

    // Returns the key set of the enumMap
    public Set<K> keySet() { return enumMap.keySet(); }

    // Returns the entry set( values + keys) of the enumMap.
    public Set<Map.Entry<K, V> > entrySet()
    {
        return enumMap.entrySet();
    }

    // Returns the value to which a specified key is mapped,
    // else returns null if the specified key is not found.

    public V get(Object key) { return enumMap.get(key); }

    // Associates the specified Key and Value.
    public V put(K key, V value)
    {
        return enumMap.put(key, value);
    }

    // Copies the mappings of another map to the specified
    // map.
    public void putAll(Map<? extends K, ? extends V> map)
    {
        enumMap.putAll(map);
    }

    // Returns the size of the enumMap.
    public int size() { return enumMap.size(); }

    // Returns the values mapped in the specified enumMap.
    public Collection<V> values()
    {
        return enumMap.values();
    }

    // Returns true if the enumMap is empty.
    public boolean isEmpty() { return enumMap.isEmpty(); }
  
    // Initializing the enumMap.
    enum Week_Days {
        SUNDAY,
        MONDAY,
        TUESDAY,
        WEDNESDAY,
        THURSDAY,
        FRIDAY,
        SATURDAY;
    }

    // Main function.
    public static void main(String[] args)
    {

        EnumMapImpl<Week_Days, Integer> enumMap
            = new EnumMapImpl<Week_Days, Integer>(Week_Days.class);
      
        enumMap.put(Week_Days.SUNDAY, 1);
        enumMap.put(Week_Days.MONDAY, 2);
        enumMap.put(Week_Days.TUESDAY, 3);
        enumMap.put(Week_Days.WEDNESDAY, 4);
        enumMap.put(Week_Days.THURSDAY, 5);
        enumMap.put(Week_Days.FRIDAY, 6);
        enumMap.put(Week_Days.SATURDAY, 7);

        System.out.println("The size of the enumMap is: "
                           + enumMap.size());
      
        System.out.println();

        System.out.println("The values of the enumMap is: ");
      
        Collection<Integer> ci = enumMap.values();
      
        Iterator<Integer> iin1 = ci.iterator();
      
        while (iin1.hasNext()) 
        {
            System.out.print(iin1.next() + "\t");
        }
      
        System.out.println();
        System.out.println();

        System.out.println("The key set of the enumMap is: ");
      
        Set<Week_Days> ws = enumMap.keySet();
      
        Iterator<Week_Days> iin2 = ws.iterator();
      
        while (iin2.hasNext()) 
        {
            System.out.print(iin2.next() + "  ");
        }
      
        System.out.println();
        System.out.println();
      
        System.out.println("The enumMap is: ");
      
        Iterator<Entry<Week_Days, Integer> > week_iterator;
      
        Set<Entry<Week_Days, Integer> > wi = enumMap.entrySet();
        week_iterator = wi.iterator();
      
        while (week_iterator.hasNext()) 
        {
            System.out.println(week_iterator.next() + "\t");
        }
      
        System.out.println();
        System.out.println("The enumMap contains Key SUNDAY "
            + ": " + enumMap.containsKey(Week_Days.SUNDAY));
      
        System.out.println("The enumMap contains Value 1 "
                           + ": "
                           + enumMap.containsValue(1));
      
        enumMap.clear();
      
        if (enumMap.isEmpty())
            System.out.println("The EnumMap is now empty.");
        else
            System.out.println("The EnumMap is not empty.");
    }
}