/**
 * The MIT License
 * Copyright (c) 2014 Ilkka Seppälä
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package com.iluwatar.memento;

import java.util.Stack;

/**
 * 
 * The Memento pattern is a software design pattern that provides the ability to restore an object
 * to its previous state (undo via rollback).
 * <p>
 * The Memento pattern is implemented with three objects: the originator, a caretaker and a memento.
 * The originator is some object that has an internal state. The caretaker is going to do something
 * to the originator, but wants to be able to undo the change. The caretaker first asks the
 * originator for a memento object. Then it does whatever operation (or sequence of operations) it
 * was going to do. To roll back to the state before the operations, it returns the memento object
 * to the originator. The memento object itself is an opaque object (one which the caretaker cannot,
 * or should not, change). When using this pattern, care should be taken if the originator may
 * change other objects or resources - the memento pattern operates on a single object.
 * <p>
 * In this example the object ({@link Star}) gives out a "memento" ({@link StarMemento}) that
 * contains the state of the object. Later on the memento can be set back to the object restoring
 * the state.
 * 
 */
public class App {

  /**
   * Program entry point
   */
  public static void main(String[] args) {
    Stack<StarMemento> states = new Stack<>();

    Star star = new Star(StarType.SUN, 10000000, 500000);
    System.out.println(star);
    states.add(star.getMemento());
    star.timePasses();
    System.out.println(star);
    states.add(star.getMemento());
    star.timePasses();
    System.out.println(star);
    states.add(star.getMemento());
    star.timePasses();
    System.out.println(star);
    states.add(star.getMemento());
    star.timePasses();
    System.out.println(star);
    while (states.size() > 0) {
      star.setMemento(states.pop());
      System.out.println(star);
    }
  }
}
