Update command pattern examples

Author: nemanjarogic

src/BehavioralPatterns/Command/CommandLibrary/EmailExample/Commands/Common/ICommand.cs

@@ -3,4 +3,4 @@
 public interface ICommand
 {
     void Execute();
-}
+}

src/BehavioralPatterns/Command/CommandLibrary/EmailExample/Commands/DeleteCommand.cs

@@ -11,8 +11,5 @@ public DeleteCommand(Email email)
         _email = email;
     }
 
-    public void Execute()
-    {
-        _email.Delete();
-    }
-}
+    public void Execute() => _email.Delete();
+}

src/BehavioralPatterns/Command/CommandLibrary/EmailExample/Commands/ForwardCommand.cs

@@ -11,8 +11,5 @@ public ForwardCommand(Email email)
         _email = email;
     }
 
-    public void Execute()
-    {
-        _email.Forward();
-    }
-}
+    public void Execute() => _email.Forward();
+}

src/BehavioralPatterns/Command/CommandLibrary/EmailExample/Commands/ReadCommand.cs

@@ -11,8 +11,5 @@ public ReadCommand(Email email)
         _email = email;
     }
 
-    public void Execute()
-    {
-        _email.Read();
-    }
-}
+    public void Execute() => _email.Read();
+}

src/BehavioralPatterns/Command/CommandLibrary/EmailExample/Email.cs

@@ -2,18 +2,9 @@
 
 public class Email
 {
-    public void Delete()
-    {
-        Console.WriteLine("Email has been deleted.");
-    }
+    public void Delete() => Console.WriteLine("Email has been deleted.");
 
-    public void Forward()
-    {
-        Console.WriteLine("Email has been forwarded.");
-    }
+    public void Forward() => Console.WriteLine("Email has been forwarded.");
 
-    public void Read()
-    {
-        Console.WriteLine("Email has been read.");
-    }
-}
+    public void Read() => Console.WriteLine("Email has been read.");
+}

src/BehavioralPatterns/Command/CommandLibrary/EmailExample/EmailExecutor.cs

@@ -21,4 +21,4 @@ public static void Execute()
         toolbar.ForwardEmail();
         toolbar.DeleteEmail();
     }
-}
+}

src/BehavioralPatterns/Command/CommandLibrary/EmailExample/Toolbar.cs

@@ -15,18 +15,9 @@ public Toolbar(ICommand readCommand, ICommand forwardCommand, ICommand deleteCom
         _deleteCommand = deleteCommand;
     }
 
-    public void ReadEmail()
-    {
-        _readCommand.Execute();
-    }
+    public void ReadEmail() => _readCommand.Execute();
 
-    public void ForwardEmail()
-    {
-        _forwardCommand.Execute();
-    }
+    public void ForwardEmail() => _forwardCommand.Execute();
 
-    public void DeleteEmail()
-    {
-        _deleteCommand.Execute();
-    }
-}
+    public void DeleteEmail() => _deleteCommand.Execute();
+}

src/BehavioralPatterns/Command/CommandLibrary/Executor.cs

@@ -15,4 +15,4 @@ public override void Execute()
         ShoppingCartExecutor.Execute();
         StockExecutor.Execute();
     }
-}
+}

src/BehavioralPatterns/Command/CommandLibrary/ShoppingCartExample/CommandManager.cs

@@ -4,20 +4,27 @@ namespace CommandLibrary.ShoppingCartExample;
 
 public class CommandManager
 {
-    private readonly Stack<ICommand> _commands = new Stack<ICommand>();
+    private readonly Stack<ICommand> _commands = new();
 
     public void Invoke(ICommand command)
     {
-        if (command.CanExecute())
+        if (!command.CanExecute())
         {
-            _commands.Push(command);
-            command.Execute();
+            return;
         }
+
+        _commands.Push(command);
+        command.Execute();
     }
 
     public void Undo()
     {
+        if (!_commands.Any())
+        {
+            return;
+        }
+
         var command = _commands.Pop();
         command.Undo();
     }
-}
+}

src/BehavioralPatterns/Command/CommandLibrary/ShoppingCartExample/Commands/AddToCartCommand.cs

@@ -20,15 +20,7 @@ public AddToCartCommand(
         _shoppingCartRepository = shoppingCartRepository;
     }
 
-    public bool CanExecute()
-    {
-        if (_product == null)
-        {
-            return false;
-        }
-
-        return _productRepository.GetStock(_product.ProductId) > 0;
-    }
+    public bool CanExecute() => _productRepository.GetStock(_product.ProductId) > 0;
 
     public void Execute()
     {
@@ -43,4 +35,4 @@ public void Undo()
         _productRepository.IncreaseStock(_product.ProductId, lineItem.Quantity);
         _shoppingCartRepository.Remove(_product.ProductId);
     }
-}
+}