//DatesCloneableTest.java
//demo clone() and Cloneable
//do not use for 241.  copy ctor can accomplish what clone() does.
//Date and IncDate are in this file for a standalone demo program.

import java.util.*;      
import javax.swing.*;

public class DatesCloneableTest {
    public static void main(String[] args) {

	IncDate date1 = new IncDate(12,23,2000);
	System.out.println("date1 starts: " + date1); 
	IncDate date2;

	date2 = date1;   
	System.out.println("date2 also starts: " + date2);  
	//date2 is a reference to the same object that date1 is a reference to.
	//date1 and date2 are aliases of each other.
	date2.increment();   //changing date2,
	System.out.println("date2 is now: " + date2);  
	System.out.println("date1 also is now: " + date1);  //changes date1


	IncDate date3;
	//clone() returns Object, so need to cast to IncDate
	date3 = (IncDate)date1.clone();    //a copy of date1, not an alias
	System.out.println(); 
	System.out.println("date3 starts: " + date3); 
	date3.increment();
	System.out.println("date3 is now: " + date3);  
	System.out.println("date1 is still: " + date1);  //does NOT change date1

	System.exit(0);
    }
}    
//***Date class overrides clone() method of Object
class Date  implements Cloneable   //same as in ch01.  ***added clone()
{
  protected int year;
  protected int month;
  protected int day;

  public Date(int newMonth, int newDay, int newYear)
  {
    month = newMonth;
    day = newDay;
    year = newYear;
   }

    //***override clone method of Object and make it public (is protected in Object)
    //***must be this signature:
    public Object clone() {
	//must be try and catch of CloneNotSupportedException
	try {
	    //call clone in Object which does shallow copy only.
	    //if class has references need deep copy; has to be more complex...
	    return super.clone();    
	} catch ( CloneNotSupportedException e) {
	    System.out.println("Cloning not allowed?!?!?");
	    return this;
	}
    }

  public int yearIs()
  {
    return year;
  }

  public int monthIs()
  {
    return month;
  }

  public int dayIs()
  {
    return day;
  }

  public String toString()
  {
    return(month + "/" + day + "/" + year);
  }

}


 class IncDate extends Date   //same as in ch01
{
  public IncDate(int newMonth, int newDay, int newYear)
  {
    super(newMonth, newDay, newYear);
   }

  public void increment()
  {
    // increment algorithm goes here
    // it updates the year, month, and day attributes
    day = day + 1;
  }
}