CSharp: Decorator Pattern in donet 6

 

    /// <summary>
    ///装饰模式 Decorator Pattern  亦称： 装饰者模式、装饰器模式、Wrapper、Decorator
    /// </summary>
    public interface IDataSource
    {

        /// <summary>
        /// 
        /// </summary>
        /// <param name="data"></param>
        void Write(string data);
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        string Read();
        /// <summary>
        /// 
        /// </summary>
        void ClearContent();
    }


 /// <summary>
    /// 装饰模式 Decorator Pattern  亦称： 装饰者模式、装饰器模式、Wrapper、Decorator
    /// </summary>
    public class File : IDataSource
    {

        /// <summary>
        /// 
        /// </summary>
        private readonly string _name;
        /// <summary>
        /// 
        /// </summary>
        private readonly StringBuilder _data;
        /// <summary>
        /// 
        /// </summary>
        /// <param name="name"></param>
        public File(string name)
        {
            _name = name;
            _data = new StringBuilder();
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="data"></param>
        public void Write(string data)
        {
            _data.Append(data);

            Console.WriteLine($"写入文件: {_name}");
            Console.WriteLine($"写成: {data}");
        }
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public string Read() => _data.ToString();
        /// <summary>
        /// 
        /// </summary>
        public void ClearContent() => _data.Clear();
    }

using Geovin.Du.DuDecorator.DataStorage.Components.Common;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Geovin.Du.DuDecorator.DataStorage.Decorators.Common
{

    /// <summary>
    /// 装饰模式 Decorator Pattern  亦称： 装饰者模式、装饰器模式、Wrapper、Decorator
    /// </summary>
    public abstract class DataSourceDecorator : IDataSource
    {

        /// <summary>
        /// 
        /// </summary>
        protected readonly IDataSource _wrapee;
        /// <summary>
        /// 
        /// </summary>
        /// <param name="dataSource"></param>
        protected DataSourceDecorator(IDataSource dataSource)
        {
            _wrapee = dataSource;
        }

        // The base decorator simply delegates all work to the wrapped component.
        // Extra behaviors can be added in concrete decorators.
        /// <summary>
        /// 
        /// </summary>
        /// <param name="data"></param>
        public virtual void Write(string data) =>
            _wrapee.Write(data);

        // 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.
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public virtual string Read() =>
            _wrapee.Read();
        /// <summary>
        /// 
        /// </summary>
        public void ClearContent() => _wrapee.ClearContent();
    }
}

  /// <summary>
    /// 装饰模式 Decorator Pattern  亦称： 装饰者模式、装饰器模式、Wrapper、Decorator
    /// </summary>
    public class CompressionDecorator : DataSourceDecorator
    {

        /// <summary>
        /// 
        /// </summary>
        private readonly string _compressionBlock;
        /// <summary>
        /// 
        /// </summary>
        /// <param name="wrapee"></param>
        public CompressionDecorator(IDataSource wrapee)
            : base(wrapee)
        {
            _compressionBlock = "--COMPRESSED--";
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="data"></param>
        public override void Write(string data)
        {
            Console.WriteLine("压缩");

            var compressedData = Compress(data);
            _wrapee.Write(compressedData);
        }
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public override string Read()
        {
            var compressedData = _wrapee.Read();
            return Decompress(compressedData);
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        private string Compress(string data) =>
            $"{_compressionBlock}{data}{_compressionBlock}";
        /// <summary>
        /// 
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        private string Decompress(string data) =>
            data.Replace(_compressionBlock, string.Empty, StringComparison.InvariantCulture);
    }


 /// <summary>
    /// 装饰模式 Decorator Pattern  亦称： 装饰者模式、装饰器模式、Wrapper、Decorator
    /// </summary>
    public class EncryptionDecorator : DataSourceDecorator
    {

        /// <summary>
        /// 
        /// </summary>
        private readonly string _encryptionBlock;
        /// <summary>
        /// 
        /// </summary>
        /// <param name="wrapee"></param>
        public EncryptionDecorator(IDataSource wrapee)
            : base(wrapee)
        {
            _encryptionBlock = "##3NCRYPT3D##";
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="data"></param>
        public override void Write(string data)
        {
            Console.WriteLine("加密");

            var encryptedData = Encrypt(data);
            _wrapee.Write(encryptedData);
        }
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public override string Read()
        {
            var encryptedData = _wrapee.Read();
            return Decrypt(encryptedData);
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        private string Encrypt(string data) =>
            $"{_encryptionBlock}{data}{_encryptionBlock}";
        /// <summary>
        /// 
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        private string Decrypt(string data) =>
            data.Replace(_encryptionBlock, string.Empty, StringComparison.InvariantCulture);



    }

 /// <summary>
    /// 装饰模式 Decorator Pattern  亦称： 装饰者模式、装饰器模式、Wrapper、Decorator
    /// </summary>
    public static class DataStorageExecutor
    {
        /// <summary>
        /// 
        /// </summary>
        public static void Execute()
        {
            ConsoleExtension.WriteSeparator("装饰模式 Decorator Pattern--Data storage demo");

            ProcessFileWithPlainData();
            ProcessFileWithCompressedData();
            ProcessFileWithCompressedAndEncryptedData();
        }
        /// <summary>
        /// 
        /// </summary>
        private static void ProcessFileWithPlainData()
        {
            IDataSource source = new Components.File("file.dat");

            WriteAndRead(source);
        }
        /// <summary>
        /// 
        /// </summary>
        private static void ProcessFileWithCompressedData()
        {
            IDataSource source = new Components.File("file.dat");
            source = new CompressionDecorator(source);

            WriteAndRead(source);
        }
        /// <summary>
        /// 
        /// </summary>
        private static void ProcessFileWithCompressedAndEncryptedData()
        {
            IDataSource source = new Components.File("file.dat");
            source = new EncryptionDecorator(source);
            source = new CompressionDecorator(source);

            WriteAndRead(source);
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="source"></param>
        private static void WriteAndRead(IDataSource source)
        {
            source.Write("Hello world");
            Console.WriteLine($"Read: {source.Read()}\n");
        }
    }

　　

调用：

       Geovin.Du.DuDecorator.DataStorage.DataStorageExecutor.Execute();
            Console.WriteLine();

　　

输出：

 

Hello, Geovin Du! 学习 .net 6

装饰模式 Decorator Pattern--Data storage demo
--------------------------------------------------
写入文件: file.dat
写成: Hello world
Read: Hello world

压缩
写入文件: file.dat
写成: --COMPRESSED--Hello world--COMPRESSED--
Read: Hello world

压缩
加密
写入文件: file.dat
写成: ##3NCRYPT3D##--COMPRESSED--Hello world--COMPRESSED--##3NCRYPT3D##
Read: Hello world