Update memento pattern examples

Author: nemanjarogic

src/BehavioralPatterns/Memento/MementoLibrary/ConceptualExample/Caretaker.cs

@@ -32,15 +32,7 @@ public void Undo()
 
         var memento = _mementos.Pop();
         Console.WriteLine($"Caretaker: Restoring state to: {memento.GetName()}");
-
-        try
-        {
-            _originator.Restore(memento);
-        }
-        catch (Exception)
-        {
-            Undo();
-        }
+        _originator.Restore(memento);
     }
 
     public void ShowHistory()
@@ -52,4 +44,4 @@ public void ShowHistory()
             Console.WriteLine(memento.GetName());
         }
     }
-}
+}

src/BehavioralPatterns/Memento/MementoLibrary/ConceptualExample/ConceptualExecutor.cs

@@ -8,8 +8,8 @@ public static void Execute()
     {
         ConsoleExtension.WriteSeparator("Conceptual example");
 
-        Originator originator = new Originator("Initial state.");
-        Caretaker caretaker = new Caretaker(originator);
+        var originator = new Originator("Initial state.");
+        var caretaker = new Caretaker(originator);
         caretaker.Backup();
 
         originator.DoSomething();
@@ -25,7 +25,7 @@ public static void Execute()
         Console.WriteLine("\nClient: Now, let's rollback!\n");
         caretaker.Undo();
 
-        Console.WriteLine("\nClient: Once more!\n");
+        Console.WriteLine("\n\nClient: Rollback once more!\n");
         caretaker.Undo();
     }
-}
+}

src/BehavioralPatterns/Memento/MementoLibrary/ConceptualExample/ConcreteMemento.cs

@@ -21,26 +21,17 @@ public ConcreteMemento(string state)
     /// The Originator uses this method when restoring its state.
     /// </summary>
     /// <returns>State.</returns>
-    public string GetState()
-    {
-        return _state;
-    }
+    public string GetState() => _state;
 
     /// <summary>
     /// Used by the Caretaker to display metadata.
     /// </summary>
     /// <returns>Name.</returns>
-    public string GetName()
-    {
-        return $"{_creationDate.ToString("MM/dd/yyyy hh:mm:ss.fff tt")} / ({_state.Substring(0, 9)})...";
-    }
+    public string GetName() => $"{_creationDate:MM/dd/yyyy hh:mm:ss.fff tt} / ({_state[..9]})...";
 
     /// <summary>
     /// Used by the Caretaker to display metadata.
     /// </summary>
     /// <returns>Creation date.</returns>
-    public DateTime GetCreationDate()
-    {
-        return _creationDate;
-    }
-}
+    public DateTime GetCreationDate() => _creationDate;
+}

src/BehavioralPatterns/Memento/MementoLibrary/ConceptualExample/IMemento.cs

@@ -8,6 +8,5 @@
 public interface IMemento
 {
     DateTime GetCreationDate();
-
     string GetName();
-}
+}

src/BehavioralPatterns/Memento/MementoLibrary/ConceptualExample/Originator.cs

@@ -11,8 +11,7 @@ public class Originator
     /// For the sake of simplicity, the originator's state is stored inside a single variable.
     /// </summary>
     private string _state;
-
-    private static readonly Random random = new Random();
+    private static readonly Random Random = new();
 
     public Originator(string state)
     {
@@ -28,20 +27,15 @@ public Originator(string state)
     public void DoSomething()
     {
         Console.WriteLine("\nOriginator: I'm doing something important.");
-
         _state = GenerateRandomString(30);
-
         Console.WriteLine($"Originator: and my state has changed to: {_state}");
     }
 
     /// <summary>
     /// Saves the current state inside a memento.
     /// </summary>
     /// <returns>Memento.</returns>
-    public IMemento Save()
-    {
-        return new ConcreteMemento(_state);
-    }
+    public IMemento Save() => new ConcreteMemento(_state);
 
     /// <summary>
     /// Restores the Originator's state from a memento object.
@@ -51,21 +45,22 @@ public void Restore(IMemento memento)
     {
         if (memento is not ConcreteMemento concreteMemento)
         {
-            throw new Exception($"Unknown memento: {memento}");
+            throw new ArgumentException($"Unknown memento: {memento}");
         }
 
         _state = concreteMemento.GetState();
         Console.Write($"Originator: My state has changed to: {_state}");
     }
 
-    private string GenerateRandomString(int length = 10)
+    private static string GenerateRandomString(int length = 10)
     {
-        string characters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
+        const string characters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
 
-        var randomCharacters = Enumerable.Repeat(characters, length)
-            .Select(s => s[random.Next(s.Length)])
+        var randomCharacters = Enumerable
+            .Repeat(characters, length)
+            .Select(s => s[Random.Next(s.Length)])
             .ToArray();
 
         return new string(randomCharacters);
     }
-}
+}

src/BehavioralPatterns/Memento/MementoLibrary/Executor.cs

@@ -13,4 +13,4 @@ public override void Execute()
         ConceptualExecutor.Execute();
         FoodSupplierExecutor.Execute();
     }
-}
+}

src/BehavioralPatterns/Memento/MementoLibrary/FoodSupplierExample/FoodSupplier.cs

@@ -2,16 +2,13 @@
 
 public class FoodSupplier
 {
-    private string _name;
-    private string _phone;
-    private string _address;
+    private string _name = string.Empty;
+    private string _phone = string.Empty;
+    private string _address = string.Empty;
 
     public string Name
     {
-        get
-        {
-            return _name;
-        }
+        get => _name;
         set
         {
             _name = value;
@@ -21,10 +18,7 @@ public string Name
 
     public string Phone
     {
-        get
-        {
-            return _phone;
-        }
+        get => _phone;
         set
         {
             _phone = value;
@@ -34,10 +28,7 @@ public string Phone
 
     public string Address
     {
-        get
-        {
-            return _address;
-        }
+        get => _address;
         set
         {
             _address = value;
@@ -64,7 +55,7 @@ public IMemento Restore(IMemento memento)
 
         if (memento is not FoodSupplierMemento foodSupplierMemento)
         {
-            throw new Exception($"Unknown memento: {memento}");
+            throw new ArgumentException($"Unknown memento: {memento}");
         }
 
         var redoMemento = new FoodSupplierMemento(_name, _phone, _address);
@@ -75,4 +66,4 @@ public IMemento Restore(IMemento memento)
 
         return redoMemento;
     }
-}
+}

src/BehavioralPatterns/Memento/MementoLibrary/FoodSupplierExample/FoodSupplierExecutor.cs

@@ -23,4 +23,4 @@ public static void Execute()
         registry.Undo();
         registry.Redo();
     }
-}
+}

src/BehavioralPatterns/Memento/MementoLibrary/FoodSupplierExample/FoodSupplierMemento.cs

@@ -10,8 +10,6 @@ public FoodSupplierMemento(string name, string phoneNumber, string address)
     }
 
     public string Name { get; set; }
-
     public string PhoneNumber { get; set; }
-
     public string Address { get; set; }
-}
+}

src/BehavioralPatterns/Memento/MementoLibrary/FoodSupplierExample/IMemento.cs

@@ -2,4 +2,4 @@
 
 public interface IMemento
 {
-}
+}