package com.citi.designpattern.singleton;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

public class SingletonTest1 implements Serializable{
    

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    private SingletonTest1(){
        
    }
    
    private static SingletonTest1 getInstance(){
        return Nested.instance;
    }
    
    static class Nested{
        private static SingletonTest1 instance = new SingletonTest1();
    }
    
    
    public static void main(String[] args) throws FileNotFoundException, IOException, ClassNotFoundException{
        //1. for not Serizable
        /*SingletonTest1 instance1 = SingletonTest1.getInstance();
        SingletonTest1 instance2 = SingletonTest1.getInstance();
        
        System.out.println(instance1 == instance2);*/
        
        //2. for Serizable 
        /*SingletonTest1 instance = SingletonTest1.getInstance();
                
        File file = new File("ser.out");
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(file));
        oos.writeObject(instance);
        oos.close();
        
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream(file));
        SingletonTest1 oIstance = (SingletonTest1)ois.readObject();
        ois.close();
        System.out.println(oIstance == instance);    */
        
        //3. overwrite writeObject and readObject
        //SingletonTest1 instance = SingletonTest1.getInstance();
        
        File file = new File("ser.out");
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(file));
        new SingletonTest1().writeObject(oos);
        oos.close();
        
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream(file));
        System.out.println(new SingletonTest1().readObject(ois) == SingletonTest1.getInstance());
        ois.close();
    }
    
    private void writeObject(ObjectOutputStream oos) throws IOException { 
        //oos.defaultWriteObject();
        oos.writeObject(SingletonTest1.getInstance());        
    }
    
    private  SingletonTest1 readObject(ObjectInputStream ois) throws IOException,  
    ClassNotFoundException { 
        //ois.defaultReadObject();
        return (SingletonTest1)ois.readObject();
    } 
    
    

}