Update composite pattern examples

Author: nemanjarogic

src/StructuralPatterns/Composite/CompositeLibrary/Executor.cs

@@ -15,4 +15,4 @@ public override void Execute()
         GiftExecutor.Execute();
         ShareholdersExecutor.Execute();
     }
-}
+}

src/StructuralPatterns/Composite/CompositeLibrary/FileSystemExample/Common/FileSystemEntry.cs

@@ -2,12 +2,12 @@
 
 public abstract class FileSystemEntry
 {
-    public FileSystemEntry(string name)
+    protected FileSystemEntry(string name)
     {
         Name = name;
     }
 
     public string Name { get; }
 
     public abstract double GetSizeInMB();
-}
+}

src/StructuralPatterns/Composite/CompositeLibrary/FileSystemExample/File.cs

@@ -12,8 +12,5 @@ public File(string name, double size)
 
     public double Size { get; }
 
-    public override double GetSizeInMB()
-    {
-        return Size;
-    }
-}
+    public override double GetSizeInMB() => Size;
+}

src/StructuralPatterns/Composite/CompositeLibrary/FileSystemExample/FileSystemExecutor.cs

@@ -18,10 +18,10 @@ public static void Execute()
         cSharpFolder.Add(new File("C#_8.0_in_a_nutshell.pdf", 11.1));
         cSharpFolder.Add(new File("C#_in_depth.pdf", 4.9));
 
-        designPatternsFolder.Add(new File("Head_first_design_patterns.pdf", 27.0));
+        designPatternsFolder.Add(new File("Head_first_design_patterns.pdf", 20.0));
 
         Console.WriteLine($"Total size of 'Books' folder: {booksFolder.GetSizeInMB()} MB");
         Console.WriteLine($"Total size of 'C#' folder: {cSharpFolder.GetSizeInMB()} MB");
         Console.WriteLine($"Total size of 'Design patterns' folder : {designPatternsFolder.GetSizeInMB()} MB");
     }
-}
+}

src/StructuralPatterns/Composite/CompositeLibrary/FileSystemExample/Folder.cs

@@ -4,26 +4,17 @@ namespace CompositeLibrary.FileSystemExample;
 
 public class Folder : FileSystemEntry
 {
-    private List<FileSystemEntry> _items;
+    private readonly List<FileSystemEntry> _items;
 
     public Folder(string name)
         : base(name)
     {
         _items = new List<FileSystemEntry>();
     }
 
-    public void Add(FileSystemEntry entry)
-    {
-        _items.Add(entry);
-    }
+    public void Add(FileSystemEntry entry) => _items.Add(entry);
 
-    public void Remove(FileSystemEntry entry)
-    {
-        _items.Remove(entry);
-    }
+    public void Remove(FileSystemEntry entry) => _items.Remove(entry);
 
-    public override double GetSizeInMB()
-    {
-        return _items.Sum(item => item.GetSizeInMB());
-    }
-}
+    public override double GetSizeInMB() => _items.Sum(item => item.GetSizeInMB());
+}

src/StructuralPatterns/Composite/CompositeLibrary/GiftExample/Common/Gift.cs

@@ -3,13 +3,13 @@
 public abstract class Gift
 {
     protected readonly string _description;
-    protected readonly decimal _price;
+    protected decimal _price;
 
-    public Gift(string description, decimal price)
+    protected Gift(string description, decimal price)
     {
         _description = description;
         _price = price;
     }
 
     public abstract decimal CalculatePrice();
-}
+}

src/StructuralPatterns/Composite/CompositeLibrary/GiftExample/Common/IGiftOperations.cs

@@ -1,10 +1,7 @@
-using CompositeLibrary.GiftExample.Common;
-
-namespace CompositeLibrary.GiftExample;
+namespace CompositeLibrary.GiftExample.Common;
 
 public interface IGiftOperations
 {
     void Add(Gift gift);
-
     void Remove(Gift gift);
-}
+}

src/StructuralPatterns/Composite/CompositeLibrary/GiftExample/CompositeGift.cs

@@ -7,35 +7,26 @@ public class CompositeGift : Gift, IGiftOperations
     /// <summary>
     /// This collection can store simple as well as composite gifts.
     /// </summary>
-    private List<Gift> _gifts;
+    private readonly List<Gift> _gifts;
 
     public CompositeGift(string description)
         : base(description, 0)
     {
         _gifts = new List<Gift>();
     }
 
-    public void Add(Gift gift)
-    {
+    public void Add(Gift gift) =>
         _gifts.Add(gift);
-    }
 
-    public void Remove(Gift gift)
-    {
-        // Consider using HashSet or Dictionary if you need remove item from a collection.
+    public void Remove(Gift gift) =>
+        // Consider using HashSet or Dictionary if you need remove an item from a collection.
         _gifts.Remove(gift);
-    }
 
     public override decimal CalculatePrice()
     {
-        decimal totalPrice = 0;
-
         Console.WriteLine($"'{_description}' contains the following products with prices:");
-        foreach (var gift in _gifts)
-        {
-            totalPrice += gift.CalculatePrice();
-        }
+        _price = _gifts.Sum(gift => gift.CalculatePrice());
 
-        return totalPrice;
+        return _price;
     }
-}
+}

src/StructuralPatterns/Composite/CompositeLibrary/GiftExample/GiftExecutor.cs

@@ -18,11 +18,8 @@ public static void Execute()
         var dadsGift = new SimpleGift("Fishing rod", 50);
         var momsGift = new SimpleGift("Necklace", 80);
         var childrenGift = new CompositeGift("Children gift");
-        var soldierToy = new SimpleGift("Soldier toy", 40);
-        var barbieToy = new SimpleGift("Barbie toy", 50);
-
-        childrenGift.Add(soldierToy);
-        childrenGift.Add(barbieToy);
+        childrenGift.Add(new SimpleGift("Soldier toy", 40));
+        childrenGift.Add(new SimpleGift("Barbie toy", 50));
 
         familyGift.Add(dadsGift);
         familyGift.Add(momsGift);
@@ -31,4 +28,4 @@ public static void Execute()
         var familyGiftPrice = familyGift.CalculatePrice();
         Console.WriteLine($"Total price for family gift: {familyGiftPrice:C}");
     }
-}
+}

src/StructuralPatterns/Composite/CompositeLibrary/GiftExample/SimpleGift.cs

@@ -12,7 +12,6 @@ public SimpleGift(string description, decimal price)
     public override decimal CalculatePrice()
     {
         Console.WriteLine($"'{_description}' with the price of {_price:C}");
-
         return _price;
     }
-}
+}