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Author: QianMo

Assets/Behavioral Patterns/Memento Pattern/Example2.meta

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+//-------------------------------------------------------------------------------------
+//	MementoExample2.cs
+//-------------------------------------------------------------------------------------
+
+using UnityEngine;
+using System.Collections.Generic;
+
+/* 
+ * provides a way to store previous states of an object easily
+ * 
+ * memento: the basic object that is stored in different states
+ * 
+ * originator: sets and gets values from the currently targeted memento. Creates new memenots and assigns current values to them
+ * 
+ * caretaker: holds an list that contains all previous versions of the memento. it can store and retrieve stored mementos
+ * 
+ * 
+ * */
+
+namespace MementoExample2
+{
+
+
+ public class MementoExample2 : MonoBehaviour
+ {
+
+ Caretaker caretaker = new Caretaker();
+
+ Originator originator = new Originator();
+
+ int savedFiles = 0, currentArticle = 0;
+
+ void Start()
+ {
+ // here we do some virtual typing and saving texts:
+ Save("Tex1: Hello World, this is text example 1");
+ Save("Text2: Ok here comes example number 2.");
+ Save("Text3: And example number 3. Just testing.");
+ Save("Text4: ....");
+
+ // Here we do some virtual button pressing
+ Debug.Log("Pressing Undo");
+ Undo();
+ Debug.Log("Pressing Undo");
+ Undo();
+ Debug.Log("Pressing Undo");
+ Undo();
+ Debug.Log("Pressing Redo");
+ Redo();
+ }
+
+
+ // these methods below might get called when someone is pressing a button
+ // you could easily implement it with unitys new ui system :)
+ public void Save(string text)
+ {
+ originator.Set(text);
+ caretaker.Add(originator.StoreInMemento());
+ savedFiles = caretaker.GetCountOfSavedArticles();
+ currentArticle = savedFiles;
+ }
+
+ public string Undo()
+ {
+ if (currentArticle > 0)
+ currentArticle -= 1;
+
+ Memento prev = caretaker.Get(currentArticle);
+ string prevArticle = originator.RestoreFromMemento(prev);
+ return prevArticle;
+ }
+
+ public string Redo()
+ {
+ if (currentArticle < savedFiles)
+ currentArticle += 1;
+
+ Memento next = caretaker.Get(currentArticle);
+ string nextArticle = originator.RestoreFromMemento(next);
+ return nextArticle;
+ }
+
+ }
+
+
+
+
+ /// <summary>
+ /// the basic object that is stored in different states
+ /// </summary>
+ public class Memento
+ {
+ public string article { get; protected set; }
+
+ // Base Memento class that in this case just stores article strings!:)
+ public Memento(string article)
+ {
+ this.article = article;
+ }
+ }
+
+
+ /// <summary>
+ /// sets and gets values from the currently targeted memento. Creates new memenots and assigns current values to them.
+ /// </summary>
+ public class Originator
+ {
+ public string article { get; protected set; }
+
+ public void Set(string article)
+ {
+ Debug.Log("From Originator: Current Version of article is: [\"" + article + "\"]");
+ this.article = article;
+ }
+
+ public Memento StoreInMemento()
+ {
+ Debug.Log("From Originator: Saving in Memento: [\"" + this.article + "\"]");
+ return new Memento(this.article);
+ }
+
+ public string RestoreFromMemento(Memento memento)
+ {
+ article = memento.article;
+ Debug.Log("From Originator: Previous Article saved in Memento: [\"" + article + "\"]");
+ return article;
+ }
+ }
+
+
+ /// <summary>
+ /// holds an list that contains all previous versions of the memento. it can store and retrieve stored mementos
+ /// </summary>
+ public class Caretaker
+ {
+ List<Memento> savedArticles = new List<Memento>();
+
+ public void Add(Memento m)
+ {
+ savedArticles.Add(m);
+ }
+
+ public Memento Get(int i)
+ {
+ return savedArticles[i];
+ }
+
+ public int GetCountOfSavedArticles()
+ {
+ return savedArticles.Count;
+ }
+ }
+
+
+}