/*
* This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
*
* The MIT License
* Copyright © 2014-2022 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;
import lombok.extern.slf4j.Slf4j;
/**
* The Memento pattern is a software design pattern that provides the ability to restore an object
* to its previous state (undo via rollback).
*
* 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.
*
*
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.
*/
@Slf4j
public class App {
/**
* Program entry point.
*/
public static void main(String[] args) {
var states = new Stack();
var star = new Star(StarType.SUN, 10000000, 500000);
LOGGER.info(star.toString());
states.add(star.getMemento());
star.timePasses();
LOGGER.info(star.toString());
states.add(star.getMemento());
star.timePasses();
LOGGER.info(star.toString());
states.add(star.getMemento());
star.timePasses();
LOGGER.info(star.toString());
states.add(star.getMemento());
star.timePasses();
LOGGER.info(star.toString());
while (!states.isEmpty()) {
star.setMemento(states.pop());
LOGGER.info(star.toString());
}
}
}