Update decorator pattern examples

Author: nemanjarogic

src/StructuralPatterns/Decorator/DecoratorLibrary/DataStorageExample/Components/Common/IDataSource.cs

@@ -5,9 +5,7 @@
 /// </summary>
 public interface IDataSource
 {
-    string Read();
-
     void Write(string data);
-
+    string Read();
     void ClearContent();
-}
+}

src/StructuralPatterns/Decorator/DecoratorLibrary/DataStorageExample/Components/File.cs

@@ -10,28 +10,23 @@ namespace DecoratorLibrary.DataStorageExample.Components;
 public class File : IDataSource
 {
     private readonly string _name;
-    private StringBuilder _data;
+    private readonly StringBuilder _data;
 
     public File(string name)
     {
         _name = name;
         _data = new StringBuilder();
     }
 
-    public void ClearContent()
-    {
-        _data.Clear();
-    }
-
-    public string Read()
-    {
-        return _data.ToString();
-    }
-
     public void Write(string data)
     {
         _data.Append(data);
 
+        Console.WriteLine($"Writing to the file: {_name}");
         Console.WriteLine($"Written: {data}");
     }
-}
+
+    public string Read() => _data.ToString();
+
+    public void ClearContent() => _data.Clear();
+}

src/StructuralPatterns/Decorator/DecoratorLibrary/DataStorageExample/DataStorageExecutor.cs

@@ -20,17 +20,15 @@ private static void ProcessFileWithPlainData()
     {
         IDataSource source = new File("file.dat");
 
-        source.Write("Hello world");
-        Console.WriteLine($"Read: {source.Read()}\n");
+        WriteAndRead(source);
     }
 
     private static void ProcessFileWithCompressedData()
     {
         IDataSource source = new File("file.dat");
         source = new CompressionDecorator(source);
 
-        source.Write("Hello world");
-        Console.WriteLine($"Read: {source.Read()}\n");
+        WriteAndRead(source);
     }
 
     private static void ProcessFileWithCompressedAndEncryptedData()
@@ -39,7 +37,12 @@ private static void ProcessFileWithCompressedAndEncryptedData()
         source = new EncryptionDecorator(source);
         source = new CompressionDecorator(source);
 
+        WriteAndRead(source);
+    }
+
+    private static void WriteAndRead(IDataSource source)
+    {
         source.Write("Hello world");
         Console.WriteLine($"Read: {source.Read()}\n");
     }
-}
+}

src/StructuralPatterns/Decorator/DecoratorLibrary/DataStorageExample/Decorators/Common/DataSourceDecorator.cs

@@ -10,30 +10,23 @@ namespace DecoratorLibrary.DataStorageExample.Decorators.Common;
 /// </summary>
 public abstract class DataSourceDecorator : IDataSource
 {
-    private readonly IDataSource _wrapee;
+    protected readonly IDataSource _wrapee;
 
-    public DataSourceDecorator(IDataSource dataSource)
+    protected DataSourceDecorator(IDataSource dataSource)
     {
         _wrapee = dataSource;
     }
 
-    public void ClearContent()
-    {
-        _wrapee.ClearContent();
-    }
+    // The base decorator simply delegates all work to the wrapped component.
+    // Extra behaviors can be added in concrete decorators.
+    public virtual void Write(string data) =>
+        _wrapee.Write(data);
 
-    public virtual string Read()
-    {
-        // Concrete decorators may call the parent implementation of the operation
-        // instead of calling the wrapped object directly.
-        // This approach simplifies extension of decorator classes.
-        return _wrapee.Read();
-    }
+    // With this approach, concrete decorators can call the parent implementation of the operation
+    // instead of calling the wrapped object directly.
+    // That simplifies extension of decorator classes.
+    public virtual string Read() =>
+        _wrapee.Read();
 
-    public virtual void Write(string data)
-    {
-        // The base decorator simply delegates all work to the wrapped component.
-        // Extra behaviors can be added in concrete decorators.
-        _wrapee.Write(data);
-    }
-}
+    public void ClearContent() => _wrapee.ClearContent();
+}

src/StructuralPatterns/Decorator/DecoratorLibrary/DataStorageExample/Decorators/CompressionDecorator.cs

@@ -10,22 +10,14 @@ namespace DecoratorLibrary.DataStorageExample.Decorators;
 /// </summary>
 public class CompressionDecorator : DataSourceDecorator
 {
-    private readonly IDataSource _wrapee;
     private readonly string _compressionBlock;
 
     public CompressionDecorator(IDataSource wrapee)
         : base(wrapee)
     {
-        _wrapee = wrapee;
         _compressionBlock = "--COMPRESSED--";
     }
 
-    public override string Read()
-    {
-        var compressedData = _wrapee.Read();
-        return Decompress(compressedData);
-    }
-
     public override void Write(string data)
     {
         Console.WriteLine("Compression");
@@ -34,13 +26,15 @@ public override void Write(string data)
         _wrapee.Write(compressedData);
     }
 
-    private string Decompress(string data)
+    public override string Read()
     {
-        return data.Replace(_compressionBlock, string.Empty);
+        var compressedData = _wrapee.Read();
+        return Decompress(compressedData);
     }
 
-    private string Compress(string data)
-    {
-        return $"{_compressionBlock}{data}{_compressionBlock}";
-    }
-}
+    private string Compress(string data) =>
+        $"{_compressionBlock}{data}{_compressionBlock}";
+
+    private string Decompress(string data) =>
+        data.Replace(_compressionBlock, string.Empty, StringComparison.InvariantCulture);
+}

src/StructuralPatterns/Decorator/DecoratorLibrary/DataStorageExample/Decorators/EncryptionDecorator.cs

@@ -10,22 +10,14 @@ namespace DecoratorLibrary.DataStorageExample.Decorators;
 /// </summary>
 public class EncryptionDecorator : DataSourceDecorator
 {
-    private readonly IDataSource _wrapee;
     private readonly string _encryptionBlock;
 
     public EncryptionDecorator(IDataSource wrapee)
         : base(wrapee)
     {
-        _wrapee = wrapee;
         _encryptionBlock = "##3NCRYPT3D##";
     }
 
-    public override string Read()
-    {
-        var encryptedData = _wrapee.Read();
-        return Decrypt(encryptedData);
-    }
-
     public override void Write(string data)
     {
         Console.WriteLine("Encryption");
@@ -34,13 +26,15 @@ public override void Write(string data)
         _wrapee.Write(encryptedData);
     }
 
-    private string Decrypt(string data)
+    public override string Read()
     {
-        return data.Replace(_encryptionBlock, string.Empty);
+        var encryptedData = _wrapee.Read();
+        return Decrypt(encryptedData);
     }
 
-    private string Encrypt(string data)
-    {
-        return $"{_encryptionBlock}{data}{_encryptionBlock}";
-    }
-}
+    private string Encrypt(string data) =>
+        $"{_encryptionBlock}{data}{_encryptionBlock}";
+
+    private string Decrypt(string data) =>
+        data.Replace(_encryptionBlock, string.Empty, StringComparison.InvariantCulture);
+}

src/StructuralPatterns/Decorator/DecoratorLibrary/PancakeExample/Components/BigPancake.cs

@@ -9,8 +9,5 @@ public BigPancake()
         Description = "Big pancake";
     }
 
-    public override double CalculatePrice()
-    {
-        return 10.0;
-    }
-}
+    public override double CalculatePrice() => 10.0;
+}

src/StructuralPatterns/Decorator/DecoratorLibrary/PancakeExample/Components/Common/Pancake.cs

@@ -2,12 +2,9 @@
 
 public abstract class Pancake
 {
-    public string Description { get; set; }
+    public string Description { get; set; } = string.Empty;
 
     public abstract double CalculatePrice();
 
-    public virtual string GetDescriptionAndAddIns()
-    {
-        return Description;
-    }
-}
+    public virtual string GetDescriptionAndAddIns() => Description;
+}

src/StructuralPatterns/Decorator/DecoratorLibrary/PancakeExample/Components/SmallPancake.cs

@@ -9,8 +9,5 @@ public SmallPancake()
         Description = "Small pancake";
     }
 
-    public override double CalculatePrice()
-    {
-        return 6.0;
-    }
-}
+    public override double CalculatePrice() => 6.0;
+}

src/StructuralPatterns/Decorator/DecoratorLibrary/PancakeExample/Decorators/Common/PancakeDecorator.cs

@@ -11,13 +11,7 @@ public PancakeDecorator(Pancake pancake)
         _pancake = pancake;
     }
 
-    public override double CalculatePrice()
-    {
-        return _pancake.CalculatePrice();
-    }
+    public override double CalculatePrice() => _pancake.CalculatePrice();
 
-    public override string GetDescriptionAndAddIns()
-    {
-        return $"{_pancake.GetDescriptionAndAddIns()}, {Description}";
-    }
-}
+    public override string GetDescriptionAndAddIns() => $"{_pancake.GetDescriptionAndAddIns()}, {Description}";
+}