JAVA EE: Java : Collection Framework : Hashtable (Values)

Wednesday 4 March 2015

Java : Collection Framework : Hashtable (Values)

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HashtableExample.java

import java.util.Collection;
import java.util.Hashtable;
import java.util.Iterator;

/*
 * Example of values() method.
 */
public class HashtableExample
{
    public static void main( String[] args )
    {

        Hashtable<String, String> hashtable = new Hashtable<String, String>();

        /*
         * Key = CountryCode,Value = CountryName.
         */
        hashtable.put("AF", "AFGHANISTAN");
        hashtable.put("BE", "BELGIUM");
        hashtable.put("US", "UNITED STATES");
        hashtable.put("IN", "INDIA");

        System.out.println("hashtable : " + hashtable + "\n");

        /*
         * Returns a Collection view of the values contained in this map. The
         * collection is backed by the map, so changes to the map are reflected
         * in the collection, and vice-versa.
         * 
         * If the map is modified while an iteration over the collection is in
         * progress (except through the iterator's own remove operation), the
         * results of the iteration are undefined. The collection supports
         * element removal, which removes the corresponding mapping from the
         * map, via the Iterator.remove, Collection.remove, removeAll, retainAll
         * and clear operations. It does not support the add or addAll
         * operations.
         */
        Collection<String> collection = hashtable.values();

        System.out.println("collection : " + collection + "\n");

        for( Iterator<String> iterator = collection.iterator(); iterator
                .hasNext(); )
        {
            String value = iterator.next();
            System.out.println(value);
        }
    }
}

Output

hashtable : {IN=INDIA, AF=AFGHANISTAN, BE=BELGIUM, US=UNITED STATES}

collection : [INDIA, AFGHANISTAN, BELGIUM, UNITED STATES]

INDIA
AFGHANISTAN
BELGIUM
UNITED STATES