package com.iluwatar;
   
   import java.io.Serializable;
   
   /**
    * The Initialize-on-demand-holder idiom is a secure way of 
    * creating lazy initialize singleton Object in Java.
    * refer to "The CERT Oracle Secure Coding Standard for Java"
    * By Dhruv Mohindra, Robert C. Seacord p.378
   * 
   * Singleton objects usually are heavy to create and sometimes need to serialize them.
   * This class also shows how to preserve singleton in Serialized version of singleton.
   * 
   * @author mortezaadi@gmail.com
   *
   */
  public class InitializingOnDemandHolderIdiom implements Serializable{
  
  	private static final long serialVersionUID = 1L;
  
  	private static class HelperHolder {
  		public static final InitializingOnDemandHolderIdiom INSTANCE = new InitializingOnDemandHolderIdiom();
  	}
  
  	public static InitializingOnDemandHolderIdiom getInstance() {
  		return HelperHolder.INSTANCE;
  	}
  
  	private InitializingOnDemandHolderIdiom() {
  	}
  
  	protected Object readResolve() {
  		return getInstance();
  	}
  
  }